Discovery of Oxygen

This tweet has been making the rounds today.

RT @greatbritain: UK discovered more elements in periodic table than any other country pic.twitter.com/yjN2BQ3QWx #museumweek

— UKTI (@UKTI) March 27, 2014

It shows each element by its nation(s) of initial discovery, except of course elements like iron which date to antiquity. Europe claims most of the 18th and 19th century elements, while the U.S. seems to dominate in the modern ones, i.e. astatine plus the transuranium elements.

Overall I think it's a fascinating chart, but I do have a couple of problems with it. One, it lists element 117 as undiscovered, despite the fact that it was synthesized by a joint U.S.-Russian team in 2010. Still, element 117 hasn't been officially accepted by the IUPAC/IUPAP, so I suppose the creators are just playing it safe.

But more importantly, I feel the chart's creators err when they assign the discovery of oxygen to England and Sweden. For the historical record, Carl Wilhelm Scheele of Sweden in 1772 and Joseph Priestley of England in 1774 both independently isolated oxygen by heating HgO and the like. Although Scheele performed his experiment first, Priestley published first, so there's some question as to which one deserves more credit-this chart seems to split the difference.

Surprising Article about Californium Chemistry

I just saw an interesting article from the RSC at Chemistry World based on this article in Nature Chemistry about the chemistry of californium. Researchers at Florida State University were supplied by the U.S. Department of Energy with several milligrams of ²⁴⁹Cf which was reported as being worth over a million dollars(!). They proceeded to synthesize a californium borate compound and they report on their experimental findings and electronic structure explanations of said findings.

The authors claim that "...there are, in fact, few parallels between lanthanide and actinide chemistry." The article continues that actinide chemistry (or californium-highly polarizable ligand chemistry, at any rate) in many respects is actually more similar to d-block behavior than expected f-block behavior.

What was particularly interesting was that the f-orbitals where also involved in bonding. The original article in Nature Chemistry discusses some DFT calculations on the californium borate, using a "60-electron core quasi-relativistic pseudopotential" for the californium. As far as I can tell, the authors where primarily concerned with scalar relativistic effects (i.e. s- and p-shell contraction and d- and f-shell expansion) rather than spin-orbit coupling. If so, the explanation for their results should be that the higher degree of s-orbital contraction in the actinides versus the lanthanides results in substantially larger f-orbitals, which are better able to form covalent bonds.

In any event, this article opens some interesting questions about heavy element chemistry, and I'm excited to seeing where it will lead.

Astatine: Halogen or Metal? Part 3: Electronic Structure Calculations

For "Part 1: Background" click here. For "Part 2: Introduction to Relativistic Quantum Chemistry" click here.

In this post I will be applying the lessons of Part 2 on relativistic quantum chemistry to discuss papers which publish significant (relativistic) electronic structure calculations of astatine. To date, I have only found two which I would put in this category; they are referenced at the end of the paper. Articles of lesser direct significance will be referenced as they come up. I will attempt to keep this blog post updated as I become aware of other articles or as they are published. If anyone is aware of any relevant articles, I would greatly appreciate if you leave a reference or link in the comments below.

Astatine: Halogen or Metal? Part 2: Introduction to Relativistic Quantum Chemistry

Click here for part 1, "Astatine: Halogen or Metal? Part 1: Background."

Note to readers: To date I have attempted to keep my posts approachable by non-chemists in an effort to provide chemical education to anyone interested. Due to the subject nature, this post will perforce be something of an exception and will contain parts that may be unaccessible to anyone without at least bachelor's level expertise in chemistry or physics. Nonetheless, I will attempt to make the conclusions accessible to a more general audience.

Astatine: Halogen or Metal? Part 1: Background

While teaching a recent general chemistry class I was asked whether astatine should be considered a halogen. I realized that throughout my undergraduate years, the halogens had always been assumed to stop at iodine, but to my embarrassment I had never fully researched why. Even its placement as element 85 begs the question, does astatine continue the vertical trend of the halogens, or the diagonal trend of the metalloids? In this series of posts I hope to address this question in a manner thorough enough for future graduate student TA's who work in other areas of chemistry, but still generally approachable to interested non-chemists.

Chemistry Book Review: The Periodic Table by Primo Levi

Primo Levi. From Wikipedia

A few years back an event organized by the Royal Institute of London named Primo Levi's The Periodic Table the best science book ever written. Although others can and have done far better jobs analyzing the philosophical and literary significance of Levi's work, I'd like to share a few of my thoughts, some from a scientific perspective.

Before reviewing the book, a brief background on Primo Levi is necessary. Levi was born in 1919 into a relatively well-to-do Jewish family in the Piedmont region of northern Italy. His entry into university to study chemistry coincided with the increase in severity of the Fascist party's laws against Jews. As a result, Levi was among the last Jews able to earn a degree in Fascist Italy. Although racial laws should have prevented Levi from gaining employment as a chemist after graduation, through a combination of an Italian army officer who&#8212in Levi's assessment&#8212"took a bitter and subtle pleasure in breaking the laws of racial separation," and subsequent employment by a Swiss firm operating in Milan, Levi managed to work as a chemist through the partition of Italy in 1943.

Professional Custom Narcotics: Real Life Breaking Bad

There was a fascinating recent article in Medium entitled The drug revolution that no one can stop. Although rather long, the piece is a great read about the medical, legal, and scientific aspects of custom narcotics.

The article discusses "psychonauts" who behave as human guinea pigs for novel, potentially physchotropic compounds (they aren't big believers in lab safety protocols). By slightly modifying known drugs and marketing them as not for human consumption, they can operate more or less inside the law for a few years until the government catches on. I won't attempt to rehash the entire article here, but I do want to point out the part that's of particular interest to me as a chemist.

The author invented a fake identity and UK based pharmaceutical company and set off searching for a contractor to synthesize a phenmetrazine like compound. After about a week he hired a Shanghai based company willing to synthesize the drug and ship in to the UK with minimal questions asked, all for only a few hundred dollars.

What really struck me was the degree of chemical expertise the Chinese company exhibited. They not only developed a synthesis route for the compound within two weeks, they then proceeded to use liquid chromatography to test its purity and even emailed an NMR spectrum of the drug before shipping. When the author received the compound, he sent it to a lab at Cardiff University, who confirmed its purity and the NMR spectrum. The Chinese company were legitimately highly trained and skilled chemists.

What's the take home message here? There will always be intelligent people willing to use their intelligence for bad (or at least morally grey) aims, and we as chemists have proven that we're no exception. Still, it hits home to see an example as blatant as this. I suppose this is how doctors feel when they read about other doctors selling narcotic prescriptions.