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April 6, 2015
p184 It’s bad to be poor, I was brooding as I held an ingot of tin from the Straits [I can not find an official definition of what is meant by "the Straits" but it must be somewhere in the East Indies] over the flame of the gas jet. Very slowly the tin melted, and the drops fell with a hiss into the water of a basin: on the basin’s bottom a fascinating metallic tangle of ever new shapes was forming.
There are friendly metals and hostile metals. Tin was a friend -- not only because, for some months now, Emilio and I were living on it, transforming it into stannous chloride to sell to the manufactures of mirrors, but also for other, more recondite reasons: because it marries with iron, transforming it into mild tin plate and depriving it on that account of its sanguinary quality of nocens ferrum [guilty iron]; because the Phoenicians traded in it and it is to this day extracted, refined, and shipped from fabulous and distant countries (the Straits, precisely: one might say the Sleepy Sonda Islands, the Happy Isles and Archipelagos [so he means the entire area formerly called the East Indies]); because it forms an alloy with copper to give us bronze, the respectable material par excellence, notoriously perennial and well established; because it melts at a low temperature, almost like organic compounds, that is, almost like us; and finally, because of two unique properties with picturesque, hardly credible names, never seen or heard (that I know) by human eye or ear, yet faithfully handed down from generation to generation by all the textbooks -- the “weeping” of tin [Here?] and tin pest.
p185 You have to granulate tin so that afterwards it can be easier to attack with hydrochloric acid. So you asked for it. You were living under the wings of that lakeshore factory, a bird of prey but with broad, strong wings. You decided to get out from under its protection, fly with your own wings: well, you asked for it. So fly now: you wanted to be free and you are free, you wanted to be a chemist and you are one. So now grub among poisons, lipsticks, and chicken shit; granulate tin, pour hydrochloric acid; concentrate, decant, and crystallize if you do not want to go hungry, and you know hunger. Buy tin and sell stannous chloride.
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p187 In the middle of the lab was a large ventilation hood of wood and glass, our pride and our only protection against death by gasing. It is not that hydrochloric acid is actually toxic: it is one of those frank enemies that comes at you shouting from a distance, and from which it is therefore easy to protect yourself. It has such a penetrating odor that whoever can wastes no time in getting out of its way; and you cannot mistake it for anything else, because after having taken in one breath of it you expel from your nose two short plumes of white smoke, like the horses in Eisenstein’s movies, and you feel your teeth turn sour in your mouth, as when you have bitten into a lemon. Despite our quite willing hood, acid fumes invaded all the rooms: the wallpaper changed color, the doorknobs and metal fixtures became dim and rough, and every so often a sinister thump made us jump: a nail had been corroded through and a picture, in some corner of the apartment, had crashed to the floor...
So we were dissolving tin in hydrochloric acid: then the solution had to be concentrated to a particular specific weight and left to crystallize by cooling. The stannous chloride separated in small, pretty prisms, colorless and transparent. Since the crystallization was slow, it required many receptacles, and since hydrochloric acid corrodes all metals, these receptacles had to be glass or ceramic. In the period when there were many orders, we had to mobilize reserve receptacles, in which for that matter Emilio’s house was rich: a soup tureen, an enameled iron pressure cooker, an Art Nouveau chandelier, and a chamber pot.
The morning after, the chloride is gathered and set to drain: and you must be very careful not to touch it with your hands or it saddles you with a truly disgusting smell. This salt, in itself, is odorless, but it reacts in some manner with the skin, perhaps reducing the keratin’s dissulfide bridges and giving off a persistent metallic stench that for several days announces to all that you are a chemist. It is aggressive but also delicate, like certain unpleasant sports opponents who whine when they lose: you can’t force it, you have to let it dry out in the air in its own good time. If you try to warm it up, even in the mildest manner, for example, with a hair dryer or on the radiator, it loses its crystallization water, becomes opaque, and foolish customers no longer want it. Foolish because it would suit them fine: with less water there is more tin and therefore more of a yield; but that’s how it is, the customer is always right, especially when he knows little chemistry, as is precisely the case with mirror manufacturers.
p188 Nothing of the generous good nature of tin, Jove’s metal, survives in its chloride (besides, chlorides in general are rabble, for the most part ignoble by-products, hygroscopic, not good for much: with the single exception of common salt, which is a completely different matter). This salt is an energetic reducing agent, that is to say, it is eager to free itself of two of its electrons and does so on the slightest pretext, sometimes with disastrous results: just a single splash of the concentrated solution, which ripped down my pants, was enough to cut them cleanly like the blow of a scimitar; and this was right after the war, and I had no other pants except my Sunday best, and there wasn’t much money in the house.
I would never have left the lakeshore factory, and I would have stayed there for all eternity correcting varnishes’ deformities, if Emilio had not insisted, praising adventure and the glories of a free profession. I had quit my job with absurd self-assurance, distributing to my colleagues and superiors a testament written in quatrains full of gay impudence: I was quite aware of the risk I was running, but I knew that the license to make mistakes becomes more limited with the passing of the years, so he who wants to take advantage of it must not wait too long. On the other hand, one must not wait too long to realize that a mistake is a mistake: at the end of each month we did our accounts, and it was becoming ever more obvious that man does not live by stannous chloride alone; or at least I did not, since I had just married and had no authoritative patriarch behind me.
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p189 Emilio accepted the common defeat and my desertion with sorrow but like a man... the next day he already had in mind other ideas, other deals with people more experienced than I, and immediately set about dismantling the laboratory, and he wasn’t even all that sad, whereas I was and felt like crying, or of howling at the moon as dogs do when they see the suitcases being closed... [During the cleanup of the place there...] rose to the surface -- and I appropriated it greedily -- a proclamation decree of 1785 in which F Tom. Lorenzo Matteucci, General Inquisitor of the Ancona District, especially delegated against the heretical depravity, with much complacency and little clarity, “orders, prohibits, and severely commands, that no Jew shall have the temerity to take Lessons from Christians for any kind of Instrument, and much less that of Dancing.”
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[They hire professionals to remove the ventilation hood and to lower it from the fourth floor of the building. The chain breaks and it falls to the courtyard floor, shattering into “shards of wood and glass” ...]
p190 In the brief instants of the flight the instinct of self-preservation made us take a leap backward. Emilio said, “I thought it would make more noise.”
Tin (Sn 50)
“Tin shows chemical similarity to both neighboring group-14 elements, germanium and lead, and has two possible oxidation states, +2 and the slightly more stable +4. Tin is the 49th most abundant element and has, with 10 stable isotopes, the largest number of stable isotopes in the periodic table. It is a silvery, malleable other metal that is not easily oxidized in air, obtained chiefly from the mineral cassiterite where it occurs as tin dioxide, SnO2.
The first alloy, used on a large scale since 3000 BC, was bronze, an alloy of tin and copper. After 600 BC, pure metallic tin was produced. Pewter, which is an alloy of 85–90% tin with the remainder commonly consisting of copper, antimony and lead, was used for flatware from the Bronze Age until the 20th century. In modern times tin is used in many alloys, most notably tin/lead soft solders, which are typically 60% or more tin. Another large application for tin is corrosion-resistant tin plating of steel. Because of its low toxicity, tin-plated metal is commonly used for food packaging as tin cans, which are made mostly of steel.”
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Physical properties
Droplet of solidified molten tin
“Tin is a malleable, ductile and highly crystalline silvery-white metal. When a bar of tin is bent, a crackling sound known as the tin cry can be heard due to the twinning of the crystals.[5] Tin melts at a low temperature of about 232 °C (450 °F), which is further reduced to 177.3 °C (351.1 °F) for 11-nm particles.[6]
β-tin (the metallic form, or white tin), which is stable at and above room temperature, is malleable. In contrast, α-tin (nonmetallic form, or gray tin), which is stable below 13.2 °C (55.8 °F), is brittle. α-tin has a diamond cubic crystal structure, similar to diamond, silicon or germanium. α-tin has no metallic properties at all because its atoms form a covalent structure where electrons cannot move freely. It is a dull-gray powdery material with no common uses, other than a few specialized semiconductor applications.[5] These two allotropes, α-tin and β-tin, are more commonly known as gray tin and white tin, respectively.”
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“Tin becomes a superconductor below 3.72 K.[10] In fact, tin was one of the first superconductors to be studied; the Meissner effect, one of the characteristic features of superconductors, was first discovered in superconducting tin crystals.[11]”
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Isotopes
“Tin has ten stable isotopes, with atomic masses of 112, 114 through 120, 122 and 124, the greatest number of any element. Of these, the most abundant ones are 120Sn (at almost a third of all tin), 118Sn, and 116Sn, while the least abundant one is 115Sn. The isotopes possessing even mass numbers have no nuclear spin while the odd ones have a spin of +1/2. Tin, with its three common isotopes116Sn, 118Sn and 120Sn, is among the easiest elements to detect and analyze by NMR spectroscopy, and its chemical shifts are referenced against SnMe4.[note 1][13]
This large number of stable isotopes is thought to be a direct result of tin possessing an atomic number of 50, which is a "magic number" in nuclear physics. There are 28 additional unstable isotopes that are known, encompassing all the remaining ones with atomic masses between 99 and 137. ”
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“The Latin name stannum originally meant an alloy of silver and lead, and came to mean 'tin' in the 4th century BCE[17]—the earlier Latin word for it was plumbum candidum, or "white lead". Stannum apparently came from an earlier stāgnum (meaning the same substance),[15] the origin of the Romance and Celtic terms for 'tin'.[15][18] The origin of stannum/stāgnum is unknown; it may be pre-Indo-European.[19] The Meyers Konversationslexikon speculates on the contrary that stannum is derived from (the ancestor of) Cornish stean, and is proof that Cornwall in the first centuries AD was the main source of tin.”
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“Tin(II) chloride (also known as stannous chloride) is the most important tin halide in a commercial sense. Illustrating the routes to such compounds, chlorine reacts with tin metal to give SnCl4 whereas the reaction of hydrochloric acid and tin gives SnCl2 and hydrogen gas. Alternatively SnCl4 and Sn combine to stannous chloride via a process called comproportionation:[25]”
SnCl4 + Sn → 2 SnCl2
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Price and exchanges
World production and price (US exchange) of tin.
“Tin is unique among other mineral commodities by the complex "agreements" between producer countries and consumer countries dating back to 1921. The earlier agreements tended to be somewhat informal and sporadic; they led to the "First International Tin Agreement" in 1956, the first of a continuously numbered series that essentially collapsed in 1985. Through this series of agreements, the International Tin Council (ITC) had a considerable effect on tin prices. The ITC supported the price of tin during periods of low prices by buying tin for its buffer stockpile and was able to restrain the price during periods of high prices by selling tin from the stockpile. This was an anti-free-market approach, designed to assure a sufficient flow of tin to consumer countries and a decent profit for producer countries. However, the buffer stockpile was not sufficiently large, and during most of those 29 years tin prices rose, sometimes sharply, especially from 1973 through 1980 when rampant inflation plagued many world economies.[47]
During the late 1970s and early 1980s, the U.S. Government tin stockpile was in an aggressive selling mode, partly to take advantage of the historically high tin prices. The sharp recession of 1981–82 proved to be quite harsh on the tin industry. Tin consumption declined dramatically. The ITC was able to avoid truly steep declines through accelerated buying for its buffer stockpile; this activity required the ITC to borrow extensively from banks and metal trading firms to augment its resources. The ITC continued to borrow until late 1985, when it reached its credit limit. Immediately, a major "tin crisis" followed — tin was delisted from trading on the London Metal Exchange for about 3 years, the ITC dissolved soon afterward, and the price of tin, now in a free-market environment, plummeted sharply to $4 per pound and remained around this level through 1990s.[47] It increased again by 2010 due to rebound in consumption following the 2008–09 world economic crisis, restocking and continued growth in consumption in the world's developing economies.[37]” -Wiki
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