Rhodium Palladium
Iridium Osmium


Platinum group metals

The book of science

Tom Sharp

William Hyde Wollaston, Smithson Tennant elements

Platinum group metals

Rhodium and palladium

Iridium and osmium



In 1807, Jędrzej Śniadecki might have isolated the sixth platinum group metal, ruthenium, which he called vestium. In 1827, Gottfried Osann thought he had isolated it, along with two other unknown metals, pluranium and polinium, and proposed a name for it based on Ruthenia, the area of Eastern Europe occupied by the Rus’ people. In 1844, Karl Ernst Claus not only isolated it but also determined its chemical properties and atomic weight, 44. The atomic weight of rhodium is 45, palladium 46, osmium 76, iridium 77, and platinum 78.

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