Artistic License Chemistry

When a work of fiction creates a new trait of a known element or compound—as opposed to Unobtainium, which generally just makes up new substances out of whole cloth. Such is usually done in service of the Rule of Cool.

There may be some overlap when real names are used for obviously fictional elements.

May very, very rarely intersect with Science Marches On, but usually this trope applies either where science has already long since marched on, or some twisted path entirely off the parade route.

Not to be confused with Elemental Rock-Paper-Scissors; granted, elements don't work that way either in Real Life. Compare Parodic Table of the Elements. Mirror Chemistry is often a specific form of this.

It is worth bearing in mind that several substances in Real Life (especially commercial medicines and cosmetics) are marketed under names that would make a proper chemist wince, and there's no reason the fictional world should be any different. Kryptonite doesn't have to have anything to do with Krypton... unless they tell you it does.

Subtropes:
 * Hollywood Acid
 * Unobtainium

Comic Books
"Selina: "Chemicals don't work that way." Joker: "My hair is green.""
 * Promethium is the DC Universe version of adamantium. In the real world, it's a radioactive metal with no stable isotopes.
 * In the Marvel Universe Promethium is used as the name of an extradimensional metal with magical properties.
 * In the DC Animated Universe (or at least insofar as Batman: Vengeance is concerned), Promethium is a chemical compound used in cryogenics. It also blows up reeeeal good, hence the name (after Prometheus, bringer of fire).
 * "Nth Metal", the substance from which Thanagarian weapons are made in the DCU. Stated in Justice League Unlimited to be "transuranic iron", whatever that means.
 * If we assume by "iron" they mean "group 8 element on the periodic table", then the first transuranic element would be hassium, which has a maximum half-life of about 10 seconds. Presumably, fights involving Thanagarians are short ones.
 * Invoked and subverted in one comic by The Joker in a discussion with Catwoman after tagging her with a radioactive isotope tracker hidden in a pie he threw at her. The whole idea was that once she had the tracer on her, the Joker could then play a twisted game of cat and mouse with her throughout Gotham (Hint: She's not the cat...). Subverted in the sense that yes, radioactive isotope tracers can work that way, and invoked in the following conversation:

Film

 * Evolution did this for selenium. They hand waved it by saying that selenium was to the alien creatures' nitrogen-based biochemistry as arsenic is to carbon-based life forms, because they're in the same relative position on the periodic table. This handwave made it clear that nobody involved in the movie understands the concept of valence electrons. Besides, the Rule of Funny dictated they had to defeat the Eldritch Abomination amoeba with gallons of anti-dandruff shampoo.
 * There is also the fact that they never tested their theory before loading tons of the shampoo into a fire truck and going after the amoeba's cloaca.
 * The original 1954 Godzilla movie has Dr. Serizawa use an invention called the Oxygen Destroyer to kill Godzilla. In the film, the device worked by dissolving oxygen molecules in the water causing asphyxiation (and also, for some odd reason, dissolving the tissues, bones, etc.) of anything unfortunate enough to get within range of it when it's used. A horrible, horrible way to die. Still, it does leave a LOT of questions on how exactly it works.
 * In the original film, it dissolved organic matter completely. in Godzilla x Mecha Godzilla it was retconned to skeletonizing, as they dredged up the first Godzilla's bones to use as the organic frame for Kiryu. Which wasn't the worst effect of the Oxygen destroyer, considering it also allowed hibernating anaerobic creatures to wake up, mutate and become the horrifying anti-life beast Destoroyah.
 * In one of the later films, Godzilla VS Mechagodzilla, it's stated that Mechagodzilla is made of Space Titanium. We would like to know how it's different from regular-old everyday titanium, which, by the way, you can already find in outer space (not least because it's a good metal for some parts of our spacecraft).
 * In Star Trek Generations, Trilithium is able to stop all fusion inside a star, causing it to implode on itself and then go supernova—thus destroying the star and all of its inner planets. This involves the same problems as "dilithium," below, plus the added problem that the writers had already given the name "trilithium" to a different fictional substance.
 * Plan 9 from Outer Space asserts that "a ray of sunlight is made up of many atoms," thus making possible the destruction of the universe by solaronite bomb. In Real Life, light is made of photons, not atoms.
 * In Spider-Man 2, Dr. Octavius requires some tritium for his experiments. He obtains it in form of a gray metallic ball. Tritium is gaseous under normal conditions, but it's possible that the gold object is a second layer of containment in addition to the glass ball around it. He also mentions how tritium is one of the rarest elements on Earth. Tritium is an isotope, not an element, and it's so common that glow in the dark watches are made with it.
 * Commercial demand for tritium is 400 grams per year[3] and the cost is approximately US $30,000 per gram.
 * Probably a joke considering it's Mars Attacks!... The Martians must wear space helmets while on Earth because they breathe Nitrogen rather than Oxygen. However, not only is Nitrogen inert, and therefore a poor "choice" as a gas to breathe, but it's the most plentiful gas in the Earth's atmosphere - i.e. there's more Nitrogen than Oxygen. However, they don't necessarily die from the lack of nitrogen - if they developed in a world without free oxygen (or other strong oxidizer; if they had to resort to nitrogen...), their "lungs" would probably rapidly oxidize. The atmosphere would be as comfortable to them as an acidic atmosphere to us.
 * In the second live-action movie, Scooby Doo freezes the Tar Monster with a fire extinguisher.
 * This is possible. Certainly with a carbon dioxide extinguisher at pressure. When you are shown how to use an extinguisher you are told not to hold the nozzle because you can freeze your hand to it...

Literature

 * The radium rifles from the John Carter of Mars series are a clear case of Science Marches On: radium was then new and poorly-understood, hence was often given whatever magic properties were required by the plot, such as repulsion rays or shrinking rays. Additionally, the nephew of John Carter adds this disclaimer: "I have used the word radium in describing this powder because in the light of recent discoveries on Earth I believe it to be a mixture of which radium is the base. In Captain Carter's manuscript it is mentioned always by the name used in the written language of Helium and is spelled in hieroglyphics which it would be difficult and useless to reproduce."
 * In the novel Ride the Gray Planet, thorium is used as a nuclear fuel, a mild example seeing as it is used as such in real life, but unlike in the book it can't be used in nuclear reactors by itself.
 * Quadium is used to power a bomb in The Mouse That Roared.
 * In the Kurt Vonnegut novel Cat's Cradle a single synthetic ice-crystal called "Ice-Nine," formed of ordinary oxygen and hydrogen, is able to freeze all liquid water that it touches, into identical crystals of "Ice-Nine" via chain-reaction—eventually freezing all water on Earth. This is impossible due to the simple state of hydrogen-bonds that form liquid H 2 O and ice, preventing any such strange isomer-crystal.
 * In season 4 of the TV show Alias, one episode features a substance called Ice Five, which is functionally identical to Vonnegut's Ice Nine.
 * At one point, the Perry Rhodan universe ran on the implicit assumption that matter and antimatter would only react with each other if matching elements and anti-elements came into contact. Thus, oxygen + anti-oxygen = boom, but, say, nitrogen + anti-oxygen = perfectly safe. (The plot revolved around peaceful visitors from an antimatter universe and the spectacular disasters their visits caused.) The initial explanation for why Ynkelonium, a heavy metallic element that didn't react with antimatter (and also conveniently suppressed such reactions in its immediate vicinity), acted the way it did was that it simply had no antimatter counterpart...
 * In H.G.Wells' War of the Worlds, the Martian's Black Smoke is said to be made of an unknown element that reacts with the Argon in the atmosphere, causing devastating effects on humans. Argon, being a noble gas, is extremely difficult to react and the reaction will never happen in the atmosphere.
 * That's really one of Wells' lesser offenses against science. The active component of the space-ship in 'The First Men in The Moon' is immune to gravity, on account of it being an alloy of helium and metal, and blocking gravity in the same means as most materials block light. Possibly a case of Unreliable Narrator, as the narrator in question admits to not taking notes.
 * In the Lensman books by E. E. "Doc" Smith, an early power source is "allotropic iron". An allotrope is a molecule consisting of one type of atom; most elements have a variety of allotropes with different properties (two allotropes of carbon are graphite and diamond). In the Lensman universe, there's one allotrope of iron that makes it into this hyperdense radioactive liquid that turns 10% of it's own mass into energy over time, making it a good fuel source for spaceships. See also Handwavium, Techno Babble, and WTF.
 * More accurately, the liquid allotrope is used because it's extremely dense, and because it's iron. His "super-atomic" power plants work by total-conversion of mass to energy, and so an extremely dense yet nonreactive liquid would actually be a very useful fuel.
 * Similarly to the Traveller example under Tabletop Games, H. Beam Piper had gadolinium as a key component of his hyperdrive engines in Space Viking.
 * Parodied in the Discworld novel The Fifth Elephant—in addition to the four elephants holding up the Disc, there was may have been a fifth that crashed to the Disc surface like a meteor and left behind a special mineral that could be mined ... namely, fat.
 * Also, the Science of Discworld books introduce several elements—chelonium, elephantigen, deitygen, and narrativium—that play a crucial role in the Discworld's cosmology and physical sciences.
 * Isaac Asimov heard Robert Silverberg make an offhand reference to "Plutonium-186" and noted that such an isotope could not possibly exist. This provided the idea that grew into the novel The Gods Themselves, part of which takes place in an Alternate Universe where that isotope can exist because nuclear forces are stronger.
 * In Andrey Livadny's The History of the Galaxy, one novel includes a presentation of a new type of Space Fighter that uses a matter/anti-matter reactor to meet its enormous power requirements. The only problem with this is the use of a rare isotope called antitritium specifically because it only reacts explosively with tritium (hydrogen-3) and no other isotope, making it safe to use. While antitritium is not normally synthesized (antideuterium has been for tests) in Real Life, the properties of antimatter mean that antitritium would not make a distinction between tritium and any other particle.

Live Action TV
"All irregularities will be handled by the forces controlling each dimension. Transuranic heavy elements may not be used where there is life. Medium atomic weights are available: Gold, Lead, Copper, Jet, Diamond, Radium, Sapphire, Silver and Steel. Sapphire and Steel have been assigned."
 * Star Trek features dilithium being used as a power regulator. Normally, dilithium would be a phrase for two covalent-bonded lithium atoms; but Star Trek ascribes it properties that allow it to regulate the matter-antimatter flow without blowing the ship to pieces. In Star Trek, the term dilithium is actually short for "2(5)6 dilithium 2l diallosilicate 1:9:1 heptoferranide", a nonexistent compound which was ascribed implausible properties. Dilithium is able to do its job because its crystal structure repels ionized particles in a magnetic field, so it can be used to regulate matter and antimatter streams, thus allowing the reaction to occur at a controlled rate, whilst allowing the resulting "warp plasma" to exit in the direction required to get it to the warp coils in the nacelles. So while not technically a fuel, if a starship has cracked dilithium crystals and no way to replace or recrystallize it, they're sunk.
 * Scotty in Star Trek 4 pointed out after they landed in 20th century Earth that "We can't even do that [recrystallize] in the 23rd century." They then proceeded to nick some fuel (actually photons (!) ) from a nuclear aircraft carrier and do just that.
 * It gets worse- the several early episodes of ST:TOS, most notably "Where No Man Has Gone Before", the successful pilot, make reference to the ship requiring lithium crystals to regulate the warp drive, and indeed the climax of "Where No Man..." takes place just outside the "lithium cracking plant" on Delta Vega. The switch from lithium to dilithium is, according to Word of God, because a number of fans and people associated with the production pointed out that lithium doesn't work like that.
 * The new film revisits Delta Vega, but retcons it from the usual Kirk's Rock to an ice planet with Bigger Fish and a 'Dilithium Cracking Plant'
 * Technically, that's a different Delta Vega. The original one is near the edge of the galaxy, while the other one is near Vulcan. The writers said that using the name as a continuity reference was more important than just coming up with a new name for a different planet, apparently...
 * According to the classic-era Trek novel How Much For Just The Planet?, dilithium does what it does because its crystalline structure extends in 4 dimensions, which is why it can only be mined, not manufactured. All atoms extend in 4 dimensions, No instantaneous cubes, you know.
 * Also, according to the same novel, dilithium apparently has a spiral lattice structure. Um, no.
 * Star Trek makes use of deuterium and anti-deuterium for powering their ships, though in Star Trek Voyager, they had a strange tendency to forget that it's just an isotope of hydrogen and thus relatively common (less than 1% of all the hydrogen in the universe, but still, there's a lot of goddamn hydrogen).
 * On one episode of Voyager the crew was astonished that some ship (stuck in a void with no interstellar gases) had stolen something as common as deuterium. Even though they got it right this time, they were still inconsistent.
 * A recurring threat in later episodes of Star Trek Voyager were the Malon, a race whose 'Hat' was of that of environment-wreckers who do so for profit. The 'Anti-Matter Waste' produced by Malon technology is highly unstable and terribly dangerous even under safe storage conditions, which makes carting it off and dumping it in someone else's backyard one of the riskiest And most profitable occupations in Malon society. ...never mind that Matter/Anti-Matter reactions result in the Total Annihilation of both leaving no physical by-products behind.
 * The radiation doesn't even activate surrounding materials, as only neutron radiation is capable of this (proton-antiproton annihilation produces only gamma rays and mesons).
 * Not entirely true. Gamma rays that energetic can easily photo-disassociate nuclei, possibly producing a radioactive nuclide.
 * The surrounding materials are blown apart by matter-antimatter annihilation. We would also expect the charged pions to change some nuclei into others radioactive or fissionable.
 * In fact, there had been a TNG episode years earlier in which terrorists invaded the drydocked Enterprise to steal a highly explosive waste product created as the ship's dilithium crystals wore down. This explosive was called "trilithium", but does not appear to bear any relation to the substance in Star Trek Generations (And Riker doesn't even recognize the name in the latter).
 * Even so it was used in an incredibly stupid fashion. Since Voyager offered a cleaner power source/way to convert the waste into something harmless locally, the garbage man turned it down (Green Aesop ho!) because it would damage the business (specifically "digging holes" variety) of slowly poisoning himself carting the shit out to the middle of nowhere. Instead of taking the technology building a station much closer to home, then using the tech and making a mountain of money due to lowered shipping cost and not killing your employees all the time.
 * The real problem with this was the idea that you could somehow contaminate cubic lightyears of space with it.
 * "Duranium-235" occasionally referenced here and there ("duranium" being a strong building material used for most sane space vessels in the Trek Verse) implies an isotope of an element... thing is, if there is an interesting property of any isotope with atomic weight 235 (protons and neutrons like to band together in particular configurations, making an atomic weight very likely to give away what element the atom is), it's almost certainly good ol' uranium (U-235 being the isotope of uranium prized for its fissile capabilities). If "duranium" is instead a future term for "depleted uranium" (a common fan theory; canon avoids clarification), well, that would be U-238.
 * As of Voyager season 1, there are supposedly 246 known elements (and in the episode where this is mentioned, they discover the next one). The ones unknown to modern science seem to have new and interesting properties, but the upper limit of the transuranic elements science has been discovering lately are invariably so extremely radioactive that they decay into more normal and stable elements very quickly. While fictional subatomic particles to differentiate things a bit more could patch up this outlandishly high number of elements, such an explanation hasn't offered... to date, anyway. (To be fair, the episode in question with the 247th element pays lip service to a "stable, transuranic element inside a natural environment" being "a first", and leaves the atomic mass at a vague "over 550", but such properties in a freakishly heavy atom are unlikely, to say the least.)
 * This may be a case of a rare instance where the Voyager production crew actually listened to its science advisor: current research in nuclear physics predicts an 'island of stability' amongst the transuranic elements somewhere beyond element 118. This is actually one of the hottest fields of study currently in nuclear physics.
 * No discussion of the Trek universe's chemistry and physics would be complete without the list of particles in Star Trek.
 * James Doohan, in order to provide consistent answers to fans as to the inner workings of the Enterprise, actually put together his own 'cheat sheet' based upon his understanding of science (he had attended a technical school where he excelled in math and science prior to his military service and acting career). During the later Trek series, both Jonathan Frakes and Robert Beltran asked the writing staff for a similar 'cheat sheet', but were disappointed to find out that by that point the science of Star Trek was being made up as the writers went along without even any internal consistency (much less accuracy to real-life).
 * Which makes one wonder why people even bother to check any more. Other than Star Trek is Serious Business, apparently.
 * Stargate SG-1 usually tried to avoid this by never clarifying what its exotic materials (naqahdah, trinium) were, compounds or elements or whatever. However, there is one big Narm for anyone who knows chemistry in the otherwise fantastic episode "The Torment of Tantalus", where both a brilliant scientist and several godlike Precursors think that electrons orbit atomic nuclei like planets around a star—something that has not been believed for decades. That could be poetic license (on the part of the characters, not the writers)--this conceit is used to create a universal language anyone could recognize if they had a very basic understanding of chemistry and physics. It's an archaeologist, and not the physicist, on SG-1 who figures out what it's supposed to be, and the "brilliant scientist"'s scientific basis dates back to the 30s.
 * Similarly, an the Star Trek the Next Generation episode "Night Terrors" had aliens providing 'one moon circles' as a clue that they needed hydrogen.
 * The scientist is well aware of what the the projection is, he even explains that it's some kind of attempt at a universal language. What he can't do is read it because he's not a linguist and can't read the code key on the walls of the room.
 * Look Around You has a Periodic Table made of funny. (And in context of the show, the chemical symbol for water is not a typo: "H20" [sic] is actually pronounced "aitch twenty".) This is in addition to the borderline insane qualities attributed to basic elements and compounds: sulphur gives you heat vision, iron causes giant scissors to materialize in the sky above you, bumcivilian (aka iron sulphide) soaks up sound waves, calcium is sentient and can melt your face, and nitrogen is the main ingredient in whiskey.
 * Excuse me, that's Iron de Havilland to the likes of you.
 * They actually state that whiskey is embenzalmine nitrotomine, which is produced by mefipulating nitrogen through water.
 * Babylon 5 attempts to avert this by claiming that Quantium-40 is an unknown isotope of potassium with unusual properties. Unfortunately, potassium-40 does exist in real life (albeit in small quantities): It's radioactive but otherwise unremarkable (except for being a major method of dating rocks, meaning that it ultimately plays the trope straight...
 * The Hand Wave given is that it's the most common of a series of quantum isotopes which have one or more of its electrons in Hyperspace which thus makes it able to open a portal to Hyperspace in mass quantities.
 * Thus making this substance a close cousin to resublimated thiotimoline.
 * In The Sarah Connor Chronicles, the main characters have to destroy a stockpile of an actual metal called coltan, which would be used to make Terminator models more advanced than the T-800 (that, being armored primarily with titanium, had a weakness to heat). Coltan is, in real-life, heat resistant, and titanium does become weaker in heat. However, coltan would be virtually useless as an armoring substance; its ability to retain an electrical charge is what makes it useful in any technology utilizing capacitors. While Terminators might be able to keep their CPUs processing despite extreme heat, therefore, they would not be any harder to render harmless with such.
 * Although, "in-universe" the fact that they used a thermite reaction to "cremate" dead terminators supposedly made of this highly heat-resistant metal is accurate. Thermite reactions are the hottest thing most people can get their hands on quietly (the simplest is rust and the powder from an Etch-a-Sketch (Aluminum)). It also burns through everything else (including steel and concrete) fairly easily.
 * House played on this trope once. In episode 48 (season 3, episode 2), a metal pin is removed from a boy who claimed to be abducted by aliens. House jokes, just for a moment, with Chase about the item being of an unidentifiable metal that might not even be terrestrial. Chase is puzzled and excited for a second, then House tells him immediately it's just ordinary titanium (it was a surgical pin that been used to set a broken arm and later worked loose).
 * Black Hole High featured two of the characters "progressing" through the periodic table, taking on, in turn, the attributes of each element they passed: one's voice becomes high-pitched and squeaky as he passes helium, then fluoresces as he passes neon; the other turns metallic at aluminum, then reeks of rotten eggs as he passes sulphur. The plot becomes a race against time to resolve the situation before one of them reaches plutonium and explodes (The solution is for them to hug as they reach sodium and chlorine respectively, creating stable and benign table salt). It doesn't take too much Fridge Logic to see the problems with this, as several of the elements along the way should have been, while perhaps not as lethal as plutonium, lethal enough. Several of the traits they demonstrated were not traits of the elements themselves.
 * And uranium, which does exactly the same thing in human-sized amounts as plutonium, is two elements before it.
 * When they were hydrogen an ignition source would create an explosion with the oxygen in the air. If they made it to lithium any amount of liquid water would react violently with the lithium, releasing the hydrogen and heat which would likely cause an explosion. Yay!
 * The opening narration from Sapphire and Steel. Spot the deliberate mistake:


 * And it is a deliberate mistake: they knew that gemstones and alloys are not elements, but it sounded cool.
 * It could also be construed as a slightly careless wording. Those materials are _made_of_ medium atomic weights and not of transuranics.
 * In Doctor Who, the Ninth Doctor deduces that the Slitheen family are calcium-based lifeforms based on the fact that they emit gases that smell like halitosis and instructs Jackie and Mickey to use splashes of vinegar to explode Sip Fel Fotch Pasameer-Day Slitheen in a shower of viscera. No part of the above sentence accurately reflects the chemistry of calcium.
 * Or the fact that bad breath is only related to tooth decay in that both are bacterial actions.
 * There's a Tales from the Crypt episode in which an ulcer-plagued soap-maker is murdered by his wife, who dumps his body in one of his rendering vats and turns him into a stack of bath products. She uses one of these soap bars in the shower, only to be fatally burned by the residual acid from his stomach ... which is impossible, as turning fats into soap requires adding enough lye to give it a neutral to alkaline pH.
 * A more subtle example than fictional elements: Battlestar Galactica Reimagined at one point attempted to suggest that organic Cylons have eight-membered rings in their biochemistry where humans have six-membered ones, and that  has seven-membered ones. For various reasons (look up "aromaticity", and also the geometric ease with which saturated six-membered rings can be formed while keeping the carbon atoms' bonds at the apexes of a tetrahedron) the prevalence of six-membered rings in Earth biochemistry is a result of fairly basic physics about how atoms bond together, and not something arbitrary that can be simplistically changed to create "alien" biology.

Music

 * An odd aversion is Kate and Anna McGarrigle's "NaCl (Sodium Chloride)" - it's actually pretty accurate (setting aside the anthropomorphizing of atoms).

Table Top Games

 * In the Traveller classic Tabletop RPG the rare earth element lanthanum was a critical material used in constructing jump drives. Assuming faster-than-light travel is possible, this may actually prove to be true, but it would be more accident than prophecy.
 * Also, in 2300 AD, from the same company (Game Designer's Workshop or GDW) the element tantalum is used in "stutterwarp drives," the type of FTL employed in that universe. Given the importance of interstellar travel, acquiring and ensuring the security of tantalum supplies is an important strategic consideration.
 * According to the Shadowtech sourcebook for Shadowrun, Ruthenium-based polymers are used in the production of cloaking suits, which can take input from several cameras and automatically change colors to hide the wearer. Ruthenium is chemically part of the platinum group and is actually very useful and versatile (as, in conjunction with other materials, a hardener, a superconductor, and a catalyst in creating certain alloys), and can actually absorb light very efficiently, but in a method useful for solar panels, not cloaking devices.
 * And let's not even think about Dicote...
 * The Space Marines of Warhammer 40000 have guns that shoot miniature rockets with depleted deuterium warheads.
 * Promethium is also used as flame(throwe)r fuel in WH40k. At least in this case it's made explicit that "promethium" is used as a catch-all term for this type of fuel, and isn't actually referring to the element.
 * 'Depleted Deuterium' in bolter rounds is particularly bad science: you can't even get depleted deuterium as it's a stable isotope. Apparently this was a spelling/editing error; the writers are still kicking themselves over it.
 * This is the Imperium, so a perfectly valid explanation would also be that they've forgotten what deuterium actually was. The vast majority of Imperial technology is recreated from templates that are over ten thousand years old, and bolters are seen in mystical terms...
 * The explanation they're going with now is that this is a deliberate lie on the part of the Adeptus Mechanicus to prevent their work from being copied & the shells are actually made of an as yet unnamed substance. This may be based on the practise of medieval alchemists writing falsehoods in their alchemical texts & hiding the real formulae in code to keep their enemies from learning their secrets.
 * Meltaguns are pretty iffy too. There's two separate descriptions on how they work (some sources say these are two different weapons that share the same function and thus are both commonly known as meltaguns). On version is that they cause thermal agitation, cooking the target alive. This explanation doesn't really break any laws of physics (although you'd need a lot of energy to heat metal to the melting point, and you'd have to keep the heat from dissipating), but the other makes considerably less sense, claiming the weapon fires a mixture of pyrol-petroleum jelly that has been forced to a sub-atomic stage and then ignited.
 * Most of WH40k's technology is explained away as being part of the fictional element/alloy "Adamantium". Other fictional alloys include "durasteel", "plasteel" and "plascrete". One of the Space Wolf novels also mentions "the hardest substance in the known universe, neutronium."
 * Rune Quest has mineable bronze. However, said bronze veins are the bones of dead gods buried under the surface of a flat world, so chemistry isn't the only science that's irrelevant here.

Video Games

 * For examples involving weapons and armor (especially prevalent in RPGs), refer to the Elemental Crafting sub-trope (aka RPG clichè #144).
 * In the Traveller 2300 game, tantalum was a vital element in the stutterwarp drive.
 * X-COM: UFO Defense has Elerium-115 being one of the most important items to collect in the game. The 115, in this case, is most likely a reference to the conspiracy theories about element 115, known today as ununpentium, as it is used in much of the same manner. (Unfortunately for them, [name]-[number] notation usually denotes an isotope, and the number is its atomic mass, not element number.)However, since the game was made ten years before ununpentium was synthesized, it's forgivable. Considering that Elerium is highly radioactive and looks a lot like Bismuth, which is one row up, they did a pretty good job.
 * Ununpentium is also, technically, a placeholder name, meaning one-one-five. This is generally considered standard practice in the scientific community until the element is renamed. So it's possible that Ununpentium might be renamed Elerium at some point (unlikely, but still...).
 * Physicists tend to have a twisted sense of humor and more geek-cred than you can shake a stick at. As long as there aren't any copyright issues (and maybe even if there are) don't be so surprised if they do name it that because of that game.
 * In old versions of Dwarf Fortress, bauxite was the only rock that magma won't melt, when there should have been many others. This is because the melting points for stones that should melt at higher temperatures weren't programmed in, and were left at the default temperature. This has been fixed in version 0.31.01 and up - nearly 30 types of stone, 6 of which form entire layers, are now "magma-safe".
 * Tiberium from Command & Conquer. However, like kryptonite in Superman Returns, it's stated to be a compound rather than an element - Tiberian Dawn gives it as 42.5% phosphorus, 32.5% iron, 15.25% calcium, 5.75% copper, 2.5% silica (itself a compound), 1.5% unknown. Tiberium crystals do absolutely nothing and their prime property is that they're valuable because of the high concentration of valuable elements. Now, the Tiberium plant, on the other hand... By the time Tiberium Wars comes around all the Tiberium on the planet has changed. It is no longer a plant but just a crystal lattice made of (green or blue) protons held together by exotic particles. When atoms brush against the lattice it smashes them to pieces and steals their protons, turning it into more Tiberium. This has caused the majority Tiberian-based mutants to die off.
 * The upcoming videogame Singularity revolves around the key to sending thing backwards and forwards in time being the mysterious "Element 99". As you can imagine, Einsteinium does not work that way.
 * Justified, as the scientists in game had discovered the element well before synthesizations of such transuranic elements existed. It's therefore feasible, but not likely, that the scientists would have just given it an element number way past anything on the then-smaller table.
 * The Sims 3 allows sims to collect mineral ores. In order of worth: Iron, Silver, Gold, Palladium, and Plutonium. In Real Life, Plutonium a whitish, radioactive metal that occurs as a result of Uranium decay. Therefore, Plutonium is dangerous and only occurs in nature when coupled with uranium ore. In The Sims 3, Plutonium is a green, naturally occurring ore that sims can carry around forever with no ill effects. However, The Sims series isn't known for realism and the developers would probably cite the Rule of Cool.
 * For that matter, palladium is intermediate in price between silver and gold rather than being more valuable than the latter; the same justification probably applies.
 * Funnily enough, you can get Tiberium, which has some interesting properties - when in your backpack, it causes your sim to develop Tiberium sickness after a while and can even kill him/her. If left alone on the ground, it will develop from "ore" to a crystal and will eventually duplicate itself. It also makes funny noises.
 * You can also get solid ignots of mercury, which are yellow-ish in color
 * And then you have metals like "mummitomium", "woohooium", "compendium", and "supernovium", the latter two of which are found by transfiguring a number of different metals together.
 * Pikmin and its sequel have several of these, most notably that oxygen gas is toxic to Olimar and his people. Somehow, his ship's life support keeps him alive, possibly meaning a form of anaerobic respiration, but the otherwise humanoid characteristics of the Hocotatians suggest that they must breathe something. Also, the glowcap mushrooms have Hocotatium-111 near critical mass accumulated in their tissues, which makes them glow. The game does get some things (potentially) right, like the suggestion that the blowhogs can make phosphorus compounds that combust upon contacting air, aided by catalysis.
 * There are actually organisms that will die if exposed to oxygen. They're all single-celled organisms, but it's not as far-fetched as it sounds.
 * In World of Warcraft One of the zeppelin manager NPCs tells you that the craft may explode "like a huge helium bomb." Then again, it was made by a goblin.
 * Well, if the zeppelin was full of helium and it exploded, then it would be "like a huge helium bomb." "Helium" in WoW may be a completely different element, like (especially) cobalt and titanium, the latter of which is almost certainly connected to the Titans.
 * Thorium in World of Warcraft is another example. In real world it's a grayish radioactive metal, but in Warcraft world it's a greenish metal that was used to make high quality armour at lv.60. Whether or not you'd want to wear a potentially radioactive pair of platemail pants is a questionable. The game notes explicitly state that the "thorium" of Azeroth is entirely unrelated to real-world thorium.
 * World of Warcraft also has various dropped items of jewelry made out of Thallium, which is both unattractive and direly toxic.
 * The 2nd expansion adds cobalt as a base for armor and weapons, which would probably not be a good idea due to the potential toxicity of its compounds (cobalt metal isn't much more toxic than iron - but it is hard to purify) and tendency for cobalt ores to contain arsenic.
 * It's also cobalt-blue, exactly like metal cobalt isn't. (The metal is shiny grayish-silver, like most transition metals.)
 * There is also Titanium, which classified as a rare metal, in real life Titanium ore is extremely common (though turning them into usable metal is another story), much more so than cobalt. Again, in the game it could be titanium is something completely different than its real life counterpart. Particularly since titanium can be transformed into Titansteel, a material with an obvious connection to the Titans who created the world.
 * Then there are things like Mithril, Truesilver, and Saronite, but for those, see Unobtainium.
 * Surprisingly, copper, tin, and iron—the first three tiers of minerals a character can mine—all behave like their real-world counterparts. Except for the fact that armor made out of them can increase their wearer's strength and agility.
 * Silver and gold, likewise, are pretty mundane as mined minerals; though for some strange reason, the vendor value for a bar of smelted gold is less than 1/10 of a gold coin—but then again, there's inflation.
 * Maple Story has Bronze Ore. Bronze, being an alloy of copper (which exists on its own) and tin, doesn't actually come from rocks. While this is probably just a case of Did Not Do the Research, Steel Ore is utterly inexcusable.
 * Not as much as you think. There are (or at least were) mines near Toledo, Spain that produced natural steel, and in the Bolivian Andes, copper miners sometimes come across (very small) veins of natural bronze. Truth and fiction are very hard to tell apart at times.
 * Runescape also uses Promethium as a metal. It is reddish and apparently incredibly resilient, making the best armour players can make with their own forge and hammer. Definitely not radioactive, definitely not unstable.
 * In the Crusader series, the Silencers' armor is made from polonium. Who knew that a soft, self-heating, unstable, toxic, radioactive, reactive, and extremely heavy element would be good for making armor?
 * Dead Space treats thermite as an explosive that blasts away a barrier made from scrap, while actually behaves a lot more like an extremely hot liquid that melts through anything. Just slapping a pack to a vertical steel plate and igniting it would only result in the whole thermite pouring down the plate to the floor and only leaving a scorch mark on the plate.
 * The gnosis from Xenosaga are made from sodium chloride or, in other words, plain salt. Anything they touch that also happens to be organic will either turn into salt or a gnosis (Still salt, but the moving kind.) Added bonus for being able to merge with mechs, becoming some sort of hybrid in the process. Don't ask how it works, even the main cast don't understand it.
 * Amnesia and its epic fail of combining aqua regia, orpiment, cuprite, and calamine all together to create simply "acid". No, the pH isn't known either.
 * Then after "acid" has been used to melt organic tissue, the glass jar it was in isn't washed out, and is re-used for something else later. After containing acid.
 * Team Fortress 2 gives us Australium, an element only found in Australia. The fact that overexposure to Australium leads to Testosterone Poisoning says a lot about accuracy in this game.
 * Based on the Australium levels in Space Chem, Australium is presumably an isotope of gold.
 * According to the Atelier Series, a vial of green and a couple of apples somehow creates pie. With crust and pan included, to boot. Want another flavor, or sprinkles or something? Toss in a hunk of metal too.
 * Vega Strike has "Dilithium Crystals" and "Trilithium Crystals" as legitimate goods (in "Raw Materials/Industrial Gems" category) according to the description, "Prized possessions of the trekkie religion, the crystals (trilithium nitride) have precious little actual value."

Western Animation

 * It's common in cartoons for gems to glow, seemingly under their own power.
 * A particularly silly example is from this Popeye short; a small emerald lights up a room.
 * Maybe that's why Popeye has those huge tumors in his arms.
 * Some diamonds do glow (to a less dramatic extent) under ultraviolet light.
 * Gold commonly emits "glow" lines in cartoons to denote its shininess. But some animators made gold objects actually glow. Like the Tiny Toons episode "Journey To The Center Of Acme Acres".
 * On an episode of The Simpsons, Homer was being coaxed to memorize the Periodic Table, to which he responds that he'll just write it on his arm. The response: "Including all KNOWN lanthanides and actinides? Good luck!" Finding new lanthanides and actinides is impossible, like finding new letters in the alphabet.
 * Actually, it's more like finding new positive integers less than 100.
 * Blame Glenn Seaborg and co, who filled in most of that gap of the periodic table in the '50s. The last was found in the 1960s, so perhaps the writer was just a baby-boomer who hadn't kept up with developments.
 * Mr. Theodor S. Geisel authored an excellent treatise on his discovery of additional letters in the English alphabet. The Other Wiki has a brief description of it here.
 * Although if the possibility of the 'g' block is counted, that would add another two periods of elements that could be classified under Lanthanides and Actinides.
 * Yeah, but those would be classified as Unbiunides and whatever-the-next-element-in-the-3d-group-would-be-I-don't-feel-like-counting-ides, not Lanthanides or Actinides. Also, they would still be in the f-block, not the g-block.
 * Parodied in an episode of the Simpsons where the classroom had a periodic table "sponsored by Oscar Meyer" with Bolognium (atomic weight: "delicious" or "snacktacular")
 * On one episode of Phineas and Ferb, the MacGuffin is an element called "Pizazzium Infinionite," which is shown on the periodic table as element 104. In real life this spot is already taken by rutherfordium, which is significantly less cool than Pizazzium apparently is.
 * This is probably just part of the show's general messing with the laws of physics. Proof of the fact is that the periodic table displayed shows Rutherfordium in its correct position and Pizzazzium Infinionite in a TINY square in the lower right. They probably named it after a company that makes periodic tables that initials itself as "Pz I" and has an identifying mark in that part of the table.
 * An Anvilicious episode of Transformers Generation 1 featured a naturally-occurring lake of electrum, a substance which inexplicably rendered Transformers invulnerable when they coated themselves with it. Not only would electrum be useless for this purpose, but no such mixture of gold and silver could be a liquid at normal outdoor temperatures. Hence, the pretty woodland glade which gets trashed in the quest for invulnerability should've been flash-fried long before the robots discovered it.
 * In the pilot miniseries of Inhumanoids, D'Compose is freed from a massive chunk of amber, then later trapped in a pit of liquid amber and re-imprisoned. While real amber softens and gets sticky when heated, it generally catches fire before it reaches its melting point. If the Redwoods had called their trap a resin pit, it wouldn't be this trope; as it is, you'd think a bunch of walking trees would know the difference between solid amber and liquid pine resin.
 * Kryptonite is Unobtanium and, to an extent, can behave however the writers want. But it's still a radioactive mineral. In the DC Animated Universe movie Superman & Batman: World's Finest, dissolving kryptonite in acid means it's "disappeared", and Superman is back to full strength. In the real world, dissolving radioactive isotopes in acid leaves you with a radioactive acid.
 * It will remain radioactive, but the change in the structure might somehow affect the radiation, making it harmless to Superman.
 * In Ben 10 Alien Force, Quartz is apparently very useful for both Time Travel and FTL Wormholes.

Other

 * Plutonium and uranium get this a lot. Their abilities are quite often exaggerated and made up, and they're usually depicted as glowing and green, not the dull gray they actually are.
 * Uranium in particular is often depicted as being far more radioactive than it actually is.
 * The different isotopes of uranium. U235 and U238 have very different uses, yet most people just assume "it's all uranium".
 * It is also depicted as being far less flammable than it actually is. Uranium and Plutonium metal are both pyrophoric and can burn when exposed to air at room temperatures. This is why depleted Uranium is the substance of choice for anti-tank projectiles as they not only punch through the armour, but also ignite whatever's inside. This is also why early nuclear reactors using Uranium metal had a tendency to catch fire. Many early reactors used graphite blocks for a moderator, compounding the problem, as proved by Chernobyl.
 * Much of this probably stems from the days when radioactivity, as it is understood today, was a new and mysterious creature, similar to how electricity was once viewed. People at one time drank water impregnated with radium, thinking it had health benefits, based on no understanding of what it would actually do to their bodies. And then their jaw falls off. Due to widespread misconceptions about radioactivity and nuclear science in general, as well as The Coconut Effect, this trope will probably self-propagate for a long time—plutonium glows green because, well, how else will viewers know it's plutonium?
 * Some radium compounds do, in fact, glow a rather eerie green - and were used, once upon a time, for everything from glow-in-the-dark paint to the aforementioned cure-all health tonics; uranium [oxide] itself was used in glassware, which fluoresces a similar colour under ultraviolet light (thus looking a bit odd even in plain sunlight). Both elements were evidently seen much the way mercury was centuries earlier: how could something that looks so awesome possibly be bad for you?
 * As a matter of fact, famous scientist Marie Curie died from her handling radioactive substances rather carelessly. She would often bring an unshielded glass vial of radium to parties, because everyone loved gazing at its beautiful glow in a darkened room. By the time she noticed a bruise that wouldn't heal, right next to the pocket she kept her radium in, she was as good as dead.
 * This was before they knew how dangerous the stuff was; how do you think we found out that radioactivity will kill you?
 * Those aren't really compounds as such... The radium is placed alongside a phosphor, the electrons of which are agitated by the radiation emitted by the radium. They jump up to a higher orbit, then drop back down again, releasing their energy as an photon in the green wavelength.
 * That is, the radiation powers the phosphorescence.
 * Alchemy. Until the 17th century or so, current views of science indicated that all matter was made out of a few 'elements' or 'qualities' (fire, air, water, and earth, most of the time). It was completely plausible, from their point of view, to change one form of matter into another by finding methods which would speed up the natural process of transmutation. Quite a few of the fathers of early science, such as Isaac Newton and Robert Boyle, were also practicing alchemists.
 * However, they were partially correct, as matter is made up of particles that individually give atoms their properties. And transmutation occurs daily in any nuclear reaction, from fusion to decay. The problem with Alchemy was mostly due to scale and the fact that it still had some lingering "magical" notions. Some things were right in front of them the whole time, like with the universal solvent - turns out its water. Nobody wanted to admit that, they just kept looking for that cool acid that dissolves everything instantaneously. Thus, alchemy isn't a science. Its Identical Grandson, chemistry, is.
 * Amusingly few alchemists came to think of where to store their magic super-acid, if it indeed dissolved anything on Earth. Around the time people started making this notion, chemistry started slowly trumping over alchemy.
 * Any form of Silicon-Based Life in Speculative Fiction is, as far as modern science concerned, silly at best. As Neil deGrasse Tyson notes in Death By Black Hole, while silicon is precisely one row below carbon and so would be almost equally as versatile in creating "living" compounds, when carbon combines with other elements, it can make both solid and "soft" materials...whereas silicon makes rocks. That's it. Rocks.
 * "A Martian Odyssey" by Stanley Weinbaum, posited a silicon based life-form which excreted waste products in the form of silicon bricks, which is piled around itself. Possibly as protection, possibly simply to be neat. These forms moved over the course of millions of years across the land leaving a row of silicon pyramids of gradually increasing size.
 * In high-temperature areas (such as deep within a planet), silicon can and does gain carbon-like properties, and many of the substances formed at such temperatures are semi-liquid. It doesn't make silicon-based creatures in most sci-fi any less silly, though; all organisms with a silicon-based biology would likely freeze to death in a volcano, so I wouldn't expect the Horta to pop up on any planetary surface, unless it was incredibly close to its star.
 * Even that wouldn't exactly work. Where carbon-carbon bonds are stable enough to require deep UV radiation to break, a silicon-silicon "organic" bond is energetic enough to be broken by visible wavelengths of light. Any planetary surface near a star would spell certain death—even an ordinary flashlight would sunburn them.
 * Still, molecules would be fairly unstable at such a temperature, including the molecules necessary to sustain the propagation of said silicon molecules, and in any case it tends to form tetragonal structures, not carbon's signature long (or short) chains.
 * Orion's Arm has the Rheoliths, slow-moving silicon-based rocklike organisms that live in the core of a certain planet. They did the research.
 * The fundamental mistake is the assumption that silicon chemistry can be made to resemble carbon chemistry beyond the "long chains" aspect. Silicon's not great at forming pi bonds, so its chemistry is severely restricted.
 * Somewhat more reasonable is the use of silicone instead of just plain silicon (as in the material in breast implants, using an alternating Si-O-Si-O chain as a backbone). You still can't just do a straight substitution. And silicon based substances in general end up either very inert (silicon rubber) or very reactive (lots of silicon-organics).
 * Respiration, as we carbon-based life forms do it, would also be impossible for Si-based life forms. CO2 is a gas. SiO2 is a solid.
 * Nucleophilic substitution happens with extreme speed at silicon. Especially if the nucleophile is hard. Polymeric silicone is exempt from rapid hydrolysis for the same reason that polymeric esters (like PET) are practically immune to acid/base catalysed hydrolysis while their shorter-chain cousins are destroyed within an hour of stirring with mild sodium hydroxide solution - steric bulk and insolubility in water. However, short-chain siloxanes would be highly vulnerable, to say the least.
 * Young Wizards states that for Silicon-based life forms, Chocolate is an Aphrodisiac.
 * Well, it does make us carbon based life-forms produce brain chemicals that make us feel like we're in love.
 * And then you have the "carbosilicate" amorphs of Schlock Mercenary... But they evolved from data storage devices, so they could well be half cells and half nanobots, or something entirely different. They find certain organic (that's in the chemical sense, bub) foods tasty, but then, Schlock demonstrated ability to consume just about any chemicals not agressive enough to eat through him first.
 * Many people in Real Life like to think of Titanium as some sort of fantastically strong Uber-Metal (Mobile Suit Gundam, we're looking right at you) when in reality it's actually no stronger than steel, it's just lighter and rust-proof.
 * But the AWESOME thing about titanium is that no known human is allergic to it, unlike any other metal, so it can be used for dental implants and orthopedic plates, pins, and screws. So from a scifi standpoint, it is the one metal you can put in your body permanently and not have to worry about. Not only that, but for no known reason human bones will graft onto Titanium quickly and easily. THIS is a big reason it's so great for implants, plates, and pins.
 * However, because it cannot be melted in air (it will burn before it melts) it cannot be welded, and it won't take solder. It can't really be welded in the presence of OXYGEN: it tend to explode. However, inside a properly purged welding chamber it isn't much more difficult to weld than most stainless steels. You just have to know what you're doing and have the proper equipment.
 * Also, it got less obvious issues, e.g. with cracks propagation. Which occasionally led to nasty surprises when someone expects Titanium to behave just like  steel, but lighter and slightly less sturdy - e.g. in DIY mountaneering equipment: it may serve without corrosion or other visible deterioration for years, then suddenly fall apart under load.
 * As for Gillette, Schick (and Wilkinson Sword) making razors out of titanium, it's partly because (as has been mentioned) no-one's allergic to the stuff, but mainly because it's more resistant to rust. Also, it still sounds pretty damn cool from a marketing standpoint.
 * Steel alloyed with titanium isn't any stronger, but is rust-resistant - and blood-red in color.
 * Speaking of diamonds, many people still seem to mistake their hardness for durability. If you ask a random person which breaks if you hit a diamond with a hammer, way too many pick the hammer. In fact, just because diamonds are hard doesn't mean that they can take any kind of punishment. Window glass is harder than a pillow, but a pillow still survives strikes that destroy the glass. If you hit a diamond with a hammer, you will get lots of little, sharp diamond shards and a hefty bill from the diamond's owner. Just because you can't scratch a substance doesn't mean you can't break it.
 * Diamonds (and volcanic glass, the most well known of them being obsidian) DO make fantastic scalpels, though. The ability to make extremely fine edges is superior to durability when the actual forces involved are that small—and glass and diamond can be made ridiculously sharp.
 * To give you an idea of how sharp volcanic glass blades could be, some mesoamerican civilizations used to make a sword called the macuahuitl; it was a wooden sword with its sides embedded with prismatic blades made from obsidian. According to an account by Bernal Diaz del Castillo, one of Hernán Cortés’s conquistadors, it could even decapitate a horse. Now that's what you call an Absurdly Sharp Blade.
 * And doing something like that would shatter the edge, ruining the weapon until the obsidian shards could be replaced. It's still glass. Sharp, but brittle.
 * Likewise diamond saw bores are mostly just small bits of diamond stuck on a plate, they're not anything super complicated or refined.
 * Real Life Comics helpfully informs us that that truck is made of truck. It's all there on the periodic table, next to beer and pretzels.
 * ThinkGeek sells salt and pepper shakers with the purported chemical formulae used to identify each on. As the main component of edible table salt, "NaCl" is acceptable to show which one should contain salt. However, "Pe+(Pe)r" is a stretch, especially so at an online store frequented by geeks and those with more than a passing interest in basic chemistry. Surely "C17H19NO3", the molecular formula for piperine, would be more apt; while piperine is only one of many constituents of black pepper, it is the compound responsible for the pungent flavouring.
 * Except it is explicitly stated that they couldn't fit the formulas of all the chemicals onto it, so they instead used Pe+(Pe)r.
 * Also, considering the site, Probably Rule of Funny and Just for Pun come into play. The funny thing about many geeks is they understand that that Pe+(Pe)r is an amusing pun on pepper, not the site being serious. Since, you know, the visitors are not actually morons.
 * It falls into YMMV pretty hard. Pe+(Pe)r makes absolutely no sense logically. If they had wanted something that was funny and still made some measure of sense, 2Pe + R would have conveyed the same thing without being overly silly.
 * Dan Brown has stated several times that, in his opinion, antimatter is the future of energy supply. He fails to realise that what he's describing is the molecular equivalent of a perpetual-motion machine—making antimatter requires a lot more energy than it releases (probably vastly more, as at present where it can only be found briefly in particle accelerators). It might, might one day be a high density fuel source but only if energy became dirt cheap anyway and we didn't have to worry about our energy supply.
 * The one way it would be possible would be to find some naturally occurring antimatter from somewhere in space. Highly improbable, but not entirely impossible. Making antimatter from ordinary mater happens one atom at a time, and making any meaningful amounts of it would take more than the current age of the universe.
 * Surprisingly enough, Brown may not be entirely wrong with his assumption after all; antimatter particles have been found in Earth's vicinity in large enough numbers that there might indeed be a thin antimatter belt of sorts within the Solar System, which would make the idea of a future powered by antimatter difficult but potentially doable.
 * You know those commercials that air promising financial compensation and legal representation for people affected by certain drugs or medical implants? Well now they're really scraping the bottom of the barrel it seems, because two of the most current advertise financial compensation for heart valve issues caused by the drug Phen-fen (or Phenfluramine, which is already known to cause heart valve issues) and liver dysfunction following the use of acetaminophen (a pain-killer already known to cause liver failure and dysfunction with overuse despite the fact every painkiller containing this drug has to warn about its effects under the Drug Warnings)! So not only do the commercials fail Chemistry forever, they also fail Pharmacology forever!