Elemental tales: Strong waters

I ran across a reference to aqua fortis in one of the commentaries in Chemical News (1891). The conversation is about a suit in court where a chemist was injured when an inappropriately packaged bottle of aqua fortis spilled. (It had a cork, and according to the rather snarky commentator, the judge — and the chemist in question — should have known that aqua fortis should not be capped with a cork.)

Aqua fortis, literally strong water, was once the common name for nitric acid. Concentrated nitric acid is a strong oxidizing agent (I can still see the small scar on my mother's hand from a spill in her undergraduate days), and I imagine would rather quickly eat away any organic matter, such as a cork. Glass would obviously be the preferred medium for storage. The suit is a frivolous one!

The term aqua fortis has fallen out of fashion, but its companion term has not: aqua regia, the royal water that would dissolve even gold. Aqua regia, as any general chemistry text will tell you, is a mix of concentrated nitric acid and concentrated hydrochloric acid (a 1:3 ratio by volume). Neither acid alone with dissolve gold (or a variety of other hard to oxidize metals), but the trick lies in the shifting equilibria.

Nitric acid is able to oxidize small amounts of gold, turning elemental gold into ions, Au³⁺. These ions then react with the chloride ions from the hydrochloric acid to form the complex ion AuCl₄^—. As the gold ions are pulled into the chloroaurate complex, the nitric acid oxidizes a bit more elemental gold. This goes on until all the solid elemental gold has been turned in chloroaurate ions floating around in solution. Imagine putting out a bowl of pretzels, as the pretzels get eaten, you try to keep it full by adding more pretzels. Eventually you run out of pretzels. The trick of using complex ion formation to drive something that isn't very soluble into solution is a common one.

Arguably the most famous example of this happened when the Nazis invaded Copenhagen. Franck and von Laue had given their 23 karat Nobel prize medals to Bohr to prevent the Nazis from confiscating them. Bohr was reluctant to bury them, sure that wherever they were hidden, a search would eventually turn them up. A chemist on staff, de Hevesy, thought to use aqua regia to dissolve the medals. After the war the gold was precipitated out and recast into medals; Franck received his recast medal in the early 1950s. Those were strong waters indeed that Bohr and de Hevesy waded into.

---

You can read a bit more about the saving of Franck and von Laue's medals at the Nobel site and see a video of aqua regia in action here.

Sex in the citadel of science

"The problem was to give birth to a boy
and not a girl," said the fathers of the atom bomb.
Marie Curie did not give birth to any joy.
Tenderly she leans toward jars of glowing radium,
as she had earlier at the bed
of her sleeping daughter Irene. (And then she bore Eve!)
Four years clothed in bitter smoke, in a shed,
stirring a mass in ebullition, nothing secretive,

an iron cauldron, iron rod nearly as big as herself,
a shed no one wanted, not fit for cadavers.
Science is the primordial interest of my life,
nor do I know whether I could live
without the laboratory. Her problem—to give breath,
to let there be light, out of slag, abandoned earth.

— from "Her Crucible: A Poem of Marie Curie" by Margaret Almon

In the latest issue of Nature Chemistry, I have a commentary speculating on why women, despite their increasing presence in the field, win the Nobel in chemistry less frequently than 100 years ago. The essay is framed around Marie Curie, the first woman to win the Nobel prize in chemistry. This year marks the 100th anniversary of Prof. Curie's Nobel (her second).

It's not about mathematical ability (sorry Larry Summers, there's hard data that punctures your theory) or lack of inherent interest. Instead, I wonder if it has to do with the built environment: the size, color, shape of the laboratory and its equipment:

Built space is not neutral, as Winston Churchill noted, “we shape our buildings, and afterwards our buildings shape us.” As much as scientists use labs to create science, labs themselves create scientists. (Read the rest here....)

Writing Science: Poetic Movements

Paul Dirac (Nobel Prize in physics, 1933) once said: "In science one tries to tell people, in such a way as to be understood by everyone, something that no one ever knew before. But in poetry, it's the exact opposite."

Is it? Can or should poetry and science mix? Should we teach scientists how to write poetry as a matter of course?




Writing Prompt
Using 2 to 5 words from the list write a poem. Stuck for form? Try haiku.
(5 syllables, 7 syllables, 5 syllables)

protein, atom, diffuse, drosophila, phylum, differential, set, scalar, momentum, graphite, ionized, equilibrium, eutrophic, entropy, catalyst, precipitate

Reading
When Science and Poetry Were Friends, an essay by Freeman Dyson
The Future of Science is Art, Jonah Lehrer, Seed Magazine
Roald Hoffman (Bio here) Individual poems here.
Sabrina Vourvoulais Fata Morgana
Karl Kirchewey, Propofol
J.C. Todd, Instant of Turbulence and Endless Caverns, in What Space This Body

---

Photo is from surrealmuse, used under a Creative Commons license.

Nobel Conversations

I vividly remember the first time I met a Nobel Prize winner. I was a graduate student in my 3rd year, and Roald Hoffman had recently won the Prize in chemistry (1981). A group of us went up with our research advisor (who had worked with Hoffman as an undergraduate) to hear him speak at a symposium at USC. On the drive up we were briefed as to behavior - do not speak unless spoken to. Frankly, we were happy enough to be out of the lab as well as treated to lunch (and to a terrific speaker). Lunch was at picnic tables in an outdoor courtyard - the grad students all clustered at a table on the edge. Imagine our surprise (and delight) when Hoffman joined us at the table, and spent lunch asking us what we were doing for research, and what excited us most about chemistry. I, at least, left with the sense that I was an interesting part of the chemical community -- even if a very junior one.

The Noble organization and Honeywell are offering the opportunity to anyone to ask a question of Nobel winners. The next live broadcast is Tuesday, March 2 at 11:15am (-6hrs GMT), when you can hear Robert Grubbs, who won the chemistry prize in 2005 for his discovery of olefin metathesis (a method to rearrange carbon-carbon double bonds using metal catalysts). I wrote my oral exam proposal on olefin metathesis in 1982 - I was fascinated then, and am still, with these atomic level architectural changes.

The best part? You can ask questions - email them to question@honeywellscience.com or go through Twitter or Facebook.

Nobel quote

After I won a Nobel Prize I suddenly turned into an omniscient sage, whereas formerly I was simply a workaholic.

Richard Ernst, Chemistry 1991

(H/T to Nature Chemistry's October editorial)









Photo of Dirac's Nobel Medal is from: rubberpaw at Flickr