Chemistry re-written… again!

A while back, I asked whether creationists had ever gone after chemistry as much as they try (and fail) to tackle biology and physics. Yes, came the unfortunate answer – and lead me to doing a quick write-up on it.

To cut it as short as I can, Artem Oganov and co. from Stony Brook University managed to make some unusual sodium chloride compounds. NaCl is common table salt, and is a classic example of how an ionic solid is created, and stabilised, by transferring one electron from where there’s an excess (in sodium) to where it’s needed (in chlorine) because that gives them 8 electrons each – the “octet rule”. Oganov’s team, however, managed to make a lot of new and strange combinations that should, on the face of it, violate this neat little principle – such as Na3Cl, Na3Cl2 and NaCl3.

To chemists, this was cool but mostly unsurprising. Solid state structures aren’t exactly known for following such arcane rules on covalency. Sodium metal itself, for instance, violates a strict and literal interpretation of the octet rule by being made purely of atoms with apparently 1 valance electron each. But to the popular press (driven by a rather naughty university press office, IMHO), this was chemistry “overturned”. A fundamental rule had been violated, chemistry must be rewritten, everything we know is wrong… and so, up steps the Discovery Institute, who declared “If chemistry is wrong, then so could evolution!

Fast forward a few years, and Oganov has done it again, and gone one better. He’s made solid state compounds of helium. Helium – the last bastion of noble gases, since xenon and krypton (and even argon, now) have known compounds.  Absurdly high pressures are needed, of course, to get helium to form a solid state structure, but the data support the compound’s existence. As with the sodium chloride, this used an evolutionary algorithm coupled to some theoretical predictions to find a structure that should, in theory, be possible before then going ahead and making the thing!

A rewrite of chemistry is needed, again, declares some of the press articles on it.

Then again, maybe not. Helium compounds are quite well known, and even a trimer of helium is known to exist at ridonkulously low temperatures where van der Waals forces will hold it together more strongly than heat can tear it apart. It’s just a case of finding the conditions where these compounds will be stable, and sufficient heat and pressure will overcome most energy barriers eventually – the activation energy to convert graphite into diamond is immense, yet natural or synthetic diamonds can still be made if we shove sufficient energy into it.

So, as before, it’s not that textbooks need re-written. The textbooks were probably wrong to start with…

Actually, not even that. I don’t recall a textbook that says all of this is outright impossible, just that it doesn’t happen easily, or in ambient conditions, with just any old reactants. Which, despite Oganov’s fantastic work, still remains shockingly true and is highly unlikely to be overturned any time… ever.

Anyway… the final question – do I want to go through the Discovery Institute looking for them misrepresenting this story?


Go on, derp away...

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