Conversations with Henry

Henry: You forgot to mention Allen and Senoff.

Me: Who? 

Henry: Allen and Senoff. They made the first dinitrogen complex from ruthenium, [Ru(NH₃)₅(N₂)]²⁺. That news caused quite a stir back in 1965. Ruthenium rhymes with iron, so you're also speculating about molybdenum. It could be iron doing the fixing in nitrogenase.  Never sell iron short.

Me: *gulps*

Henry: I'm glad to see that you're reading and keeping up with newer stuff. Barry told me you'd be back.

A Conservative Notion of Energy

Julius von Mayer (1814-1878)

The relation between food and work is intuitive: eat or die.* We also think that overeating can be offset by exercise and modern treadmills enable this thinking by showing us calories burned. And while the relation between food and work now seems intuitive, the equivalence of heat and work--or more precisely their interconversion--was a non obvious deduction.

Non obvious because work seems focused--while heat seems dispersed. It took centuries of sustained effort by thinkers and scientists to get us where we are today: that heat and work are equivalent and can interconvert.  Along the way, one man nearly took his own life for want of attention: Julius von Mayer.  His story involved blood, and indirectly, iron. To him we owe the First Law of Thermodynamics:

Energy can be neither created nor destroyed. It can only change forms

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*The German verb sterben, to die, is etymologically linked to our verb to starve.

What It Takes To Win

Stepping back for a moment from the comfort of my cocoon which eschews hackneyed political "greenery," I asked myself:

What objective indicia would gauge the public's position on things green?

The answer should be an unbiased scientific poll. According to new research out of Stanford (link), it's a little known fact that in past elections, candidates who strongly supported green energy initiatives won. If Republicans and Independents can leverage these ideas in 2012, they'll sweep back into power.

Animal Magnetism and the Lure of Bad Ideas

[This post was inspired by seeing a horse with magnetic bracelets around its fetlocks; the animal was undergoing "magnetic therapy treatment."]

Magnets fascinate us because they act at a distance -- both attracting and repelling.  Lodestone (the name literally means "leading stone") was so named for its navigational utility. There was a time when magnetism was consigned to inanimate things -- and then just mostly to iron. Ironically, magnetic navigation by birds and other animals appears to rely on magnetite.

As long as magnetism remains a mysterious force, it will find uses in medicine and alternative therapies. Discredited science and pseudo-science can die out and then return in vigor, once new discoveries occur. Such is the case for animal magnetism.

Around 1784, pre-revolutionary Paris was enthralled by Franz Mesmer, whose schtick was to pass magnets over people and cure them of alleged physical and mental ailments. Louis XVI (or his courtiers) was concerned enough to task the learned heads at the time to look into the matter. A Royal Commission included Antoine Lavoisier and Benjamin Franklin, among others. To make a long but interesting story short, the Royal Commission debunked Mesmer and he faded into near obscurity, leaving behind only the verb "to mesmerize." The whole story was brilliantly translated and retold by Stephen Jay Gould in his Bully For Brontosaurus.

Around 1845, Michael Faraday discovered that all matter responds to magnetic fields, albeit weakly and then only in the presence of very strong fields. Faraday named this remarkable property diamagnetism (though he did not explain its origins). Faraday's discovery briefly reenergized a belief in animal magnetism.

Faraday also discovered the paramagnetism of oxygen (he used soap bubbles filled with O₂ rather than liquid oxygen). Faraday developed a theory that atmospheric oxygen is seasonally influenced by the earth's magnetic field via temperature. He later abandoned this brainchild.*
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*Frank A.J.L. James, Michael Faraday: A Very Short Introduction, Oxford University Press (2010)

Steelies

The best way to destroy the capitalist system is to debase the currency. -- V.I. Lenin

If we ever get into another full scale shooting war, it's going to cost dearly just to buy all the brass needed to make ammo casings (shells) for bullets.  We've traditionally made them out of brass (copper alloyed with a little zinc).  The Russians and Chinese make their bullet casings out of steel. Because spent cartridges are essentially thrown away on the battlefield, perhaps this is not a bad idea.

We traditionally made pennies out of copper and its alloys: chart  Since 1982, the U.S. Mint has made pennies out of zinc coated with thin layer of copper to keep up appearances. As of 2010, it cost the Mint 1.79 cents to make a penny because of the costs of the penny's materials and production.

As a kid, I used to go to the bank and buy rolls of pennies. Back then (the late 1960's to early '70's) I could still find lots of bronze "wheat pennies" in circulation. I'd comb through change looking to fill those Blue Whitman folders with pennies. Except for the really rare ones, or the pre-WW II ones in good condition, I did all right. Once and a while I'd find a 1943 steel penny.  I could find them easily in a pile of pennies using a magnet. I got 3 or 4 steel pennies that way. I had to buy the "S" one though. Coins minted in San Francisco were always harder to come by east of the Rockies. And the ones I got were never as nice looking as the one in the photo:

1943-s Steel Cent

Men of Iron and Steel

The Iron Bridge at Ironbridge, Shropshire, England (Original)

A Briton named Abraham Darby ignited the industrial revolution around 1710 when he substituted coke (from coal) in his recipe for ironmaking. Traditionally, iron ore had been smelted using charcoal derived from trees (charcoal is "cleaner" carbon). Learning to smelt iron with coke in blast furnaces ultimately freed the iron industry from the natural limits of forests, much like the invention of the automobile would later free arable land from the yoke of producing fodder for horses. Three generations of Darbys stoked the wrought iron age.

Perhaps the most iconic monuments wrought from iron are Gustave Eiffel's eponymous tower in Paris (1889) and the first Ferris Wheel erected in Chicago in 1893 by George Ferris, Jr.  Eiffel also designed and produced the wrought iron framework beneath the copper sheathing of our Statue of Liberty. But even these structures were out of date when they were completed.

By the mid-1800's the demand for wrought iron was so great that inventor Henry Bessemer developed and patented the first modern process for making steel (steel is essentially purified pig iron alloyed with other metals). Vastly superior to wrought iron, Bessemer's steel revolution was so successful that it returned wrought iron making to a cottage industry. European steel maker Alfred Krupp adopted the process, and built his company on cannons and railroad wheels. Andrew Carnegie brought the same process to America but also began buying ore-rich land in Minnesota, developing a vertically integrated business model. By the time Carnegie sold his immense fortune to J.P. Morgan in 1901, the price of steel rails had fallen from $160 per ton to $17 per ton. Carnegie devoted the rest of his life to philanthropy, perhaps returning to the promise of an earlier self.*

Subsequent, more efficient processes eventually supplanted the Bessemer process, including the Open Hearth Process, the Basic Oxygen Process and the Electric Arc Process, first patented by Carl Wilhelm Siemens in 1878.

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*In December 1868, Carnegie wrote in a "memo to self:" 

Man must have an idol and the amassing of wealth is one of the worst species of idolatry! No idol is more debasing than the worship of money! Whatever I engage in I must push inordinately; therefore should I be careful to choose that life which will be the most elevating in its character. To continue much longer overwhelmed by business cares and with most of my thoughts wholly upon the way to make more money in the shortest time, must degrade me beyond hope of permanent recovery. I will resign business at thirty-five, but during these ensuing two years I wish to spend the afternoons in receiving instruction and in reading systematically!  Link

Cold Iron is master of them all! 

Stability And Instability Juxtaposed

As the universe ages, more and more matter is converted into iron-56.

...binding energy is greatest for iron
...nuclei lighter than iron are produced by fusion in stars
...nuclei heavier than iron are made in shockwave of supernova implosion
...we are all recycled star dust Link

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Whatever iron has the most of, technetium lacks: all isotopes of technetium are unstable.

Whatever makes iron the most stable nucleus and all technetium so unstable is beyond my pay grade. Link  I do find their diagonal juxtaposition in the Periodic Table intriguing:

It's almost like opposites attract.

Blut und Eisen

The bond between blood and iron is ancient. The alchemist's symbol for iron is the same as the astrological one for the red planet and the god of war, Mars.* It's also the "male" symbol.

They say that blood smells and tastes like iron. I don't think this is literally true, but somewhere, back in time, someone no doubt burned blood and got rust. That's my theory for how the bond was first established.

Hematite (original)

The word hematite for high-grade iron ore has been around since the 16th century and it means "blood-ore". Lots of hematite was mined from Minnesota to feed the heart of the steel industry down stream. The high grade stuff is played out but there's still lots of taconite.

Ironically, the red color of blood doesn't come from iron: Fe(II) is light blue in color and Fe(III) is yellowish brown. The intense color comes instead from the molecular scaffold supporting iron atoms in hemoglobin. A ring of rings, with each little ring bearing a nitrogen base, stabilizes an iron, which otherwise would irreversibly find oxygen and turn to rust.  The so-called porphyrin ring supports the otherwise unstable iron and allows it to reversibly bind and transport oxygen throughout the bloodstream. The word porphyrin comes from the Greek word meaning purple. Even with central iron atom plucked out, porphyrin is a deep purple in color.

There's lots of blood history surrounding the word porphyrin. King George III famously suffered from porphyria. Could this be the source of our political term blue blood? There's more medical history on porphyria here.
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*The reddish color of Mars comes from a skin-deep layer of iron oxides.

Cold Iron

GOLD is for the mistress -- silver for the maid --
Copper for the craftsman cunning at his trade.
"Good!" said the Baron, sitting in his hall,
"But Iron -- Cold Iron -- is master of them all."

from Cold Iron by Rudyard Kipling (1910)

Conversations with Henry: I'm Your Hapten

[This post is a continuation-in-part of the previous post]

Henry: What Wilkinson first gave the world now goes by a name. It's called hapticity.

Me: I know what hapticity is, but I didn't realize the word was Cotton's idea.

Henry: Yep.  Cotton was Geoff Wilkinson's first student.

Me: Did you know him?

Henry: Of course! Both of them.

[pause]

Henry:  I suppose the notion was there all along, sort of half-baked.

Me: What was?

Henry: Hapticity-the notion that a metal could latch onto several carbons simultaneously.  I mean, there was Zeise's salt, known since the 1820's, yet nobody knew its structure. That sure changed quickly.  Then along came Dewar and Chatt, your heroes, to explain it all! [Henry laughs]

Me:  They're not my heroes! Well maybe Dewar was.

Henry: And then there was Reihlen's iron butadiene complex. That was like an open-faced sandwich! [Henry laughs again]. Geoff knew all his work too--even though the war hid some of it. It still does.

Me: You make it all sound so obvious!

Henry:  No, Geoff just proved Pasteur's old dictum that chance favors the prepared mind.

Irony

Iron has so much history that I may have to make a little hash tag label for it like I did for carbon with bloghetti carbonara. There is just too much for one blog post.

In my last year in college at Madison, I took a graduate level course (Chem 714) called Organometallic Chemistry of the Transition Elements. I may have been the only undergraduate in the course. One of the reading assignments was called "The Iron Sandwich. A Recollection Of The First Four Months" by Geoffrey Wilkinson (Journal of Organometallic Chemistry 1975, 100, 273-278).

Wilkinson narrates the story of how he deduced the correct structure of ferrocene, shortly after its incorrect structure was first published. The work was seminal and led (in part) to his sharing the 1973 Nobel Prize in Chemistry along with E. O. Fischer of Munich.

Here he sets the stage (annoying footnotes are mine):

In early September of 1951, I arrived at 12 Oxford Street, Cambridge, Mass., as a new Assistant Professor in the Harvard Chemistry Department. I owed my appointment largely to my nuclear background. Harvard had originally intended to appoint a tenure member in nuclear chemistry, a plan which did not materialize, and had settled for myself and an Instructor, Dick Diamond, a newly graduated Ph.D. from Seaborg's laboratory in Berkeley. I was given a laboratory in the Mallinkrodt Laboratory, and went to work collecting chemicals and apparatus and built myself a small vacuum line.*

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* By vacuum line, Wilkinson means a glass tube contraption having numerous valves and fittings designed to allow working in the absence of air. Organometallic chemistry included many interesting chemical species which reacted with atmospheric oxygen- see for example the contemporaneous catalysts Ziegler was exploring an ocean away.

Wilkinson went on to describe adjusting to Harvard faculty life in a chatty way before focusing on his eureka moment:

So the story for me actually began on Friday, I think 30th January, 1952. I normally went into the Departmental Library lateish on Friday afternoons, and as usual I picked up Nature, in which I found the celebrated note by Kealy and Pauson.*  On seeing the structure...I can remember immediately saying to myself  "Jesus Christ it can't be that!"

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*T.J. Kealy and P.L. Pauson, Nature, 168 (1951) p. 1039.

Wilkinson intuited that the published structure was wrong because it was inconsistent with any other existing iron compound. The published structure (above) implied that a central iron latched onto just one carbon of each five-sided carbon ring (cyclopentadienyl). In a flash of insight, Wilkinson immediately sketched what was later redrafted for publication as:

He proposed the two hourglass-shaped structures differing only in how the five-sided rings (the bread slices of the iron sandwich) aligned with each other. He quickly went on to show that other sandwich structures existed for other metals, discovering a new genus of compounds now generically called metallocenes.

One irony in this story is that Harvard failed to offer Wilkinson tenure after he did this prize-worthy work, despite the widespread acclaim it engendered during his time there.  Harvard either didn't recognize the importance of his work or, as I suspect, he made some academic enemies there.

I recently found myself at an informal meeting of chemists and a story regarding Harvard Chemistry came up: "Yeah, Harvard--they never tenure anybody" a friend said.  After sixty years, they haven't shaken that reputation. To many, Harvard broke the code of not rewarding merit.

Wilkinson's subsequent career certainly didn't suffer.  He went on to chair the Department at Imperial College in London. He wrote an outstanding textbook used by generations of chemists. He discovered "Wilkinson's catalyst" (something that became near and dear to me).

The tenure story gets better when Harvard's Robert Burns Woodward is considered. Woodward is a co-author on the original ferrocene paper with Wilkinson but did not share that prize with Wilkinson. Woodward, perhaps the greatest American organic chemist ever, had previously won a Nobel Prize alone and probably would have shared another--had he lived--but not this one. Wilkinson thought that Woodward had had the same flash of insight as he. But did he? You can read the story for yourself here,* retold by Professor Roald Hoffmann of Cornell University.  Hoffmann knew Woodward. They shared a Nobel Prize together. But that's another story worthy of bloghetti carbonara.
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*Warning: Hoffmann invokes Rashomon, and quite aptly I think.

Manganese Is Neither Transgendered Nor Racist

The words manganese and magnesium are related. Their entwined roots stem back to a place called Magnesia in ancient Greece where they were both found in abundance. Some speculate that Spartan swords were exceptionally hard because of manganese content in their iron. Manganese's word history is parsed here and van der Krogt has his take here.

Manganese has been used since antiquity both to color and to decolorize glass. The Venetians perfected "glassmaker's soap," making high art with it.  Glass always contains iron in trace amounts and this imparts a greenish "coke bottle" tinge. The addition of manganese to the molten glass produces a reddish-brown tinge which equalizes the absorption across the visible spectrum and gives so-called colorless glass. More reading on colored glass can be found here.

Manganese also demarcates an important trend in the Periodic Table. Moving from left to right across the first transition metal series, i.e., Sc -> Ti -> V -> Cr -> Mn, each element adds one more positive charge to its core (and one surrounding electron). Yet those electrons can be stripped by oxygen. A tipping point is reached between manganese and iron. Manganese is the last metal in that series to exhaustively lose all of its valence electrons to oxygen. Thus the manganese atom in permanganate MnO₄^-, is fully oxidized back to having an argon core. But moving just one element further to the right (to iron) is just enough change in electronegativity that iron retains two valence electrons: there is a ferrate but no perferrate.

Ironically, despite its reputation for rusting, iron retains an inner core of two valence electrons, even when completely surrounded by rapacious oxygen. Iron is one step closer to the noble metals.