Sunday, May 23, 2010

Postperovskite, a high-density material named after the mineral perovskite

Perovskite, CaTiO3, is a naturally occurring mineral with a hardness of 5.5 on Mohs scale and a specific gravity of 4.0 [1]. It was first found in the Ural mountains. This mineral is named after the Russian mineralogist L. A. Perovski (1792-1856) [2]. The name perovskite also stands for the class of compounds which have the same type of crystal structure as perovskite. This perovskite structure is, for example, found in magnesium silicate (MgSiO3), which makes up 70 percent (by weight) of the perovskite layer in earth's lower mantle [3].

Postperovskite is a synthetic material or material phase observed in the laboratory under high temperature and very high pressure simulating conditions at the deep-earth boundary between the lower mantle and the outer core. Kei Hirose tells the story of its discovery and name [3]. Here, an excerpt about its name and relation to known crystalline materials is selected:
We decided to name the new phase postperovskite. (Strictly speaking, it is not a mineral, because it has yet to be found in nature.) As it turns out, its structure is essentially identical to that of two known crystals, uranium ferrous sulfate (UFeS3) and calcium iridiate (CaIrO3), which are stable under ambient conditions. And our direct measurements have shown that the density of postperovskite is indeed higher than that of perovskite, by 1 to 1.5 percent.
A postperovskite layer is assumed to exist in the inner earth at a depth of 2,600 to 2,900 km, as a phase that is formed by transformation of perovskite. Interestingly, this layer at the lowermost mantle could not have been formed in the “early earth” (2.3 billion years ago and before) when temperatures were too hot.

Keywords: earth sciences, mineralogy, earth mantle, crystal structure, high pressure, calcium titanium oxide, magnesium silicate

Dictionary of Geology & Mineralogy. McGraw Hill. Second Edition. 2003.
[3] Kei Hirose: The Earth's Missing Ingredient. Scientific American June 2010, Volume 302, Number 6, pp. 76-83.

Saturday, May 22, 2010

Atlantic Puffins and puffineers

The word puffineer is derived from the noun puffin, denoting seabird species in the auk family (Alcinae). During summer months, puffineers live in the midst of seabird colonies on islands off the coast of Maine [1], where they study the Atlantic Puffin. This bird species was almost extinct along the coast of the northeastern Unites States, but has successfully been re-introduced.

The Atlantic Puffin (Fratercula arctica) is also known as the Common Puffin. The Atlantic Puffin's Range stretches from Novaya Zemlya, Svalbard, Norway, Iceland, the United Kingdom, and Ireland to Greenland and eastern Canada. Six nesting sites, such as Eastern Egg Rock, are currently established in Maine.

Nicknames for the Atlantic Puffins are “sea parrot” and “clown of the ocean,” referring to the circus-style behavior with a wobbly, slapstick walk and the colorful, facial markings. The German name, for example, is Papageitaucher [2], meaning diving parrot. Is there a German word for puffineer? Maybe the composed noun Papageitauchkundler.

[1] Michelle Nijhuis:
Comeback! Thanks to a young biologist's unconventional ideas, Atlantic puffins have returned to the United States. Smithsonian Magazine June 2010, Volume 41, Number 3, pp. 58-65.
[2] Grzimeks TierlebenAchter BandVögel 2, page 233.

Monday, May 17, 2010

Short notation in chemistry: HBOB for bis(oxalato)boric acid

Bis(oxalato)boric acid (HBOB) is an organoborate acid. It consists formally of a proton and a boron(3+) cation that is chelated by two bidentate ethanedioato (oxalato) ligands, each contributing two negative electronic charges.

HBOB has been studied as a mild acid catalysts in the living cationic polymerization of styrene in the ionic liquid N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)amide [1]. The fact, that HBOB acts as an acid initiator in styrene polymerization under the investigated conditions, was substantiated by substituting the hydrogen of HBOB by a tetramethylammonium cation, producing the neutral salt tetramethylammonium bis(oxalato)borate (Me4NBOB), which did not exhibit any catalyst activity when used instead of HBOB.

Other salts of HBOB are also known, for example lithium bis(oxalato)borate (LiBOB) [CASRN: 244761-29-3].

HBOB also stands as an abbreviation for Honda Battle Of the Bands, Hanging Body Opponent Bag, and Hand Brushed Old Bronze [2].

Keywords: cationic polymerization of vinyl monomers, Lewis acids, catalyst recycling

[1] R. Vijayaraghavan and D. R. MacFarlane: Living cationic polymerisation of styrene in an ionic liquid. Che. Commun. 2004, 700-701. DOI: 10.1039/b315100j.

Thursday, May 6, 2010

An acronym in economics and geopolitics: BRIC for Brazil, Russia, India and China

Brazil, Russia, India and China are commonly referred to as BRIC to highlight their economical development and their advances in technology, contrasting BRIC with the rest of the world.

Whereas the PIIGS countries—another acronym built from the first letters of country names—are typically mentioned in context of financial crisis, the BRIC nations are mostly viewed and discussed as fast-developing countries and emerging markets. These countries do not form an economic bloc or a political alliance in the way the European Union does—and to which it tries to hold on.

The BRIC countries, located on two different continents, are politically, culturally, and economically diverse. Each has its own currency. And they differ in their regulatory frameworks and financial transparencies, making long-term planning, investment and risk assessment a complex task.

Brazil and Russia are important suppliers of raw materials. India and China are important suppliers of manufactured goods. It has been speculated (at Goldmann Sachs and elsewhere) that the BRIC countries would dominant the world by 2050 economically. More likely, interdependence of BRIC with NAFTA, EU and other regions will keep any dominance in check.

Finally, there remains the interesting question if our financial future will unfold in Thomas Friedman's Flat World (the hot and crowded one to be saved by a green revolution) or in David Smick's Curved World (the one with all the hidden dangers to the global economy) or in another, completely Unexpected World with groupings and alliances for which we don't have acronyms yet.

Wednesday, May 5, 2010

A new acronym in economics and geopolitics: PIIGS for Portugal, Ireland, Italy, Greece and Spain

The PIIGS nations are Portugal, Ireland, Italy, Greece and Spain. These five European countries—all in the Mediterranean region, except Ireland— are lately often found to be grouped together due to credibility and debt concerns.

I am wondering about the order in which they are listed and acronymized. Shouldn't Greece come first regarding the current situation of difficult bailout talks, strikes and riots? Maybe someone was looking for an acronym that looks and sounds similar to the plural form of the English word pig?

Some people see Great Britain in a financial crisis and are turning PIIGS into PIIGGS. But if Great Britain is in a crisis, isn't the United Kingdom as well and shouldn't we talk about PIIGUKS?

As the crisis is going to quell and more nations are stumbling we may get a very long acronym. In the United States, the crisis, mismanagement, debt, and budget cuts touches (hits) the many states differently. But they haven't been grouped by acronyms yet.