Tin plague

Zinn-ozydverbia uig, /. stannic compound, tin(IV) compound, -pest, /. tin plague, tin pest, -pfanne,/. (Tinning) tin pot. -platte, /. tin plate, sheet of tin (plate). 

It may well be that the tin plague is largely responsible for the paucity of ancient objects of pure tin. The addition of lead to tin appears to retard this change and it is worthy of note that of many hundreds of Roman tin objects that have survived until present times and have been examined all contain some lead. A soldier s button, which microscopic examination shows to have been cast, contained 0-84 per cent of lead a jug from Glastonbury, 12 22 a cup 4 49 and a coffin from Ilchester, Somerset, 55 31 of lead, this last-named alloy being close to common solder in composition. On the whole, the Romans used a wide range of alloys of the two metals ranging from 4 1 to I 4, and presumably determined by experience which alloys were best suited for any particular purpose. ... 

Another difference between tin and lead is that tin exists in two common crystalline forms (a and j8), whereas lead has but a single solid form. The a (gray), or nonmetallic, form of tin is stable below 13 °C the /3 (white), or metallic, form of tin is stable above 13 °C. Ordinarily, when a sample of /3 tin is cooled, it must be kept below 13 °C for a long time before the transition to a tin occurs. Once it does begin, however, the transformation takes place rather rapidly and with dramatic results. Because a tin is less dense than the )8 variety, the tin expands and crumbles to a powder. This transformation leads to the disintegration of objects made of tin. It has been a particular problem in churches in colder climates because some organ pipes are made of tin or tin alloys. The transformation is known in northern Europe as tin disease, tin pest, or tin plague. 

Crystalline, diastereomerieally pure syn-aIdols are also available from chiral A-acylsultams. lhe outcome of the induction can be controlled by appropriate choice of the counterion in the cnolate boron enolates lead, almost exclusively, to one adduct 27 (d.r. >97 3, major adduct/ sum of all other diastereomers) whereas mediation of the addition by lithium or tin leads to the predominant formation of adducts 28. Unfortunately, the latter reaction is plagued by lower induced stereoselectivity (d.r. 66 34 to 88 12, defined as above). In both cases, however, diastereomerieally pure adducts are available by recrystallizing the crude adducts. Esters can be liberated by treatment of the adducts with lithium hydroxide/hydrogen peroxide, whereby the chiral auxiliary reagent can be recovered106. 

Metallic tin exists in two allotropes. White tin, or (3-tin, is a silvery-white, electrically conducting, metal, with a distorted cubic structure. Below about 10 °C, it slowly coverts into grey tin, or a-tin, with a 26% increase in volume, which creates excrescences on the surface, called tin pest or plague. a-Tin is a semiconductor with a diamond structure, with A//f = 2.51 kJ moP compared with metalhc tin. ... 

Introduction. With the initial purpose of generating acyl radicals under oxidative conditions and avoiding the well-known problems of separation, toxicity, and disposal that plague many tin... 

It should be emphasized once again, however, that conditions under which metastannic acid is formed are usually avoided like the plague in radiochemical separation procedures. - If it is formed in a carrier-free solution. before tin carrier is added, the isotopic exchange problem can be formidable. 

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