Osmium history

The history of asymmetric dihydroxylation51 dates back 1912 when Hoffmann showed, for the first time, that osmium tetroxide could be used catalytically in the presence of a secondary oxygen donor such as sodium or potassium chlorate for the cA-dihydroxylation of olefins.52 About 30 years later, Criegee et al.53 discovered a dramatic rate enhancement in the osmylation of alkene induced by tertiary amines, and this finding paved the way for asymmetric dihydroxylation of olefins. 

The earliest scientific descriptions of platinum, are those of Dr. Brownrigg and Don Antonio de UUoa in the middle of the eighteenth century. Rhodium, palladium, osmium, and iridium were discovered in 1803 and 1804, the first two by Dr. Wollaston and the others by his friend, Smithson Tennant. Thomsons History of Chemistry and Berzelius correspondence and diary present a pleasing picture of these two great English chemists. Ruthenium, the Russian member of the platinum family, was discovered much later by Karl Karlovich Klaus, whose life story was beautifully told by Professor B. N Menschutkin of the Polytechnic Institute of Leningrad. 

Tennant gave the name iridium to the metal which Descotils and Vauquelin had observed, and the name osmium to the new one (20). In speaking of iridium, osmium, palladium, and rhodium, W. T. Braude stated in his lectures in 1817, Of these, the two former were discovered by the late Mr. Tennant and the two latter by Dr. Wollaston and bad we searched throughout chemistry for an illustrative instance of the delicacy of the modem art of analysis, it would be difficult to have found any one more notorious than the history of the discovery and separation of these bodies exhibits (46). During the entire course of the researches which led to ibe discovery of these four metals, Dr. Wollaston and Tennant had friendly intercourse with each other, and each kept in close touch with... 

Occurrence and History.—Osmium occurs in nature alloyed with iridium as iridosmine or osmiridium, which is found as irregular flattened grains and, more rarely, as hexagonal prisms. It has a metallic lustre, tin-white to light steel-grey in appearance hardness 6-7 density 19-3 to 21-12.1 It occurs in Choco, South America in the Urals in auriferous and other drifts in New South Wales in auriferous beach-sands of North California and also in gold washings of certain Canadian rivers.1... 

Occurronco and History of Osmium -Preparation -Properties Colloidal Osmium—Catalytic Activity—Atomic Weight—Uses Alloys. 

Since osmium was first isolated as the tetroxide, one of its most important and celebrated coordination complexes, a brief account of the history of its coordination chemistry is not out of place. The tetroxide, and subsequently the metal, was first isolated in 1803 by Smithson Tennant1 (1761-1815) by distillation with nitric acid of the black material derived after aqua regia treatment of platinum metal concentrates. Of the tetroxide Tennant wrote ... 

Two kinds of metal are found in chondrites grains composed of refractory elements (iridium, osmium, ruthenium, molybdenum, tungsten, and rhenium), which condense along with the refractory oxides above —1,600 K at 10 atm, and grains composed predominantly of iron, cobalt, and nickel, which condense with forster-ite and enstatite at —1,350-1,450 K. The former are associated with CAIs (Palme and Wlotzka 1976) and the latter with chondrules, typically type I or FeO-poor chondrules (B J 1998, pp. 244-278). Unfortunately, few chondrites preserve a good record of the formation history... 

The marine strontium isotope record is the proxy record most commonly used to constrain the geologic history of chemical weathering. However, in recent years it has been widely criticized as a proxy indicator of past silicate weathering rates. The osmium isotope record is analogous to the strontium record in many respects, and can help to constrain interpretations of the marine strontium isotope record. In this section the geochemical factors that influence the osmium and strontium isotope compositions of seawater are reviewed, and the structure of these two records of Cenozoic ocean chemistry is discussed. 

The history of Cenozoic variations in the osmium isotopic composition of seawater is also... 

Some history. The development of the current state of the art makes an interesting story. The reaction of osmium tetroxide with olefins was discovered14 in the 1930s. The reaction first gives an osmate ester 86. This ester is a stable species but can be hydrolysed to yield the diol 80. 

History. Osmium was discovered in 1803 by Smithson Tennant in the dark colored residue left when crude platinum is dissolved by aqua regia. This dark residue contains both osmium (named after the Greek osme, meaning odor) and iridium. It is a bluish-white, silvery, extremely hard brittle metal that is not malleable even at high temperatures. 

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