From Iron Man movie. I knew Tony Star was rich, but I didn't know he was a whole tank of palladium hexafluoride rich.

In continuing the theme of chemistry in the marvel films, in Iron Man 2 Tony gets the idea for a new element with a certain number of protons neutrons and electrons, and then suddenly can make it. As though the idea of a new element is the hard part and not the making it part.

Tony is also injected by Natasha with "lithium dioxide" to cure him of his palladium poisoning? S.H.I.E.L.D must have some pretty avanced chemists because LiO2 has only been isolated in a matrix. https://en.m.wikipedia.org/wiki/Lithium_superoxide

On to The Avengers. Banner tells SHIELD to call every lab in the US, put their "spectrometers" on the roof and "calibrate them for gamma rays". Imma just go ahead and put my IR machine on the roof and find some gamma rays!

Now for some somewhat correct chemistry. Dr. Eric Selvig says that they need iridium because it "forms antiprotons". While not technically incorrect, I guess we can assume he has a particle accelerator in his basement.

Noble metal chemists: if this isn't how you are storing your iridium, you are doing it wrong.

It's been a few movies since some chemistry references, but in Spiderman: Homecoming, Peter mentions "strontium, barium, vibranium" as an answer to an unknown question. This implies that vibranium is in group 2, making it an alkaline earth metal!

Peter's web formula includes salicylic acid, methanol and "toulene".

In addition to that atrocious structure of potassium carbonate, we also have this monstrosity. Come on, Peter, you are supposed to be a genius.