Three 1-gram samples of rhodium
9 August 2024
Rhodium is a hard, silvery-white metallic chemical element with atomic number 45 and the symbol Rh. Rhodium is quite rare, chiefly found as a component of platinum and nickel ores. It has a number of applications, including as a catalyst in chemical reactions, especially in automobile catalytic converters; in electrical contacts; in electroplating gold and silver jewelry; and in neutron detectors in nuclear reactors.
It was discovered in 1804 by William Hyde Wollaston in platinum ores. Wollaston coined the name rhodium from the Greek ῥόδον (rodon, meaning rose) + ‑ium because of the color of its chlorine salts, writing in the 1804 edition of Philosophical Transactions:
My inquiries having terminated more successfully than I had expected, I design in the present Memoir to prove the existence, and to examine the properties, of another metal, hitherto unknown, which may not improperly be distinguished by the name of Rhodium, from the rose-colour of a dilute solution of the salts containing it.
Rhodium was originally given the symbol Ro, which can be found in older texts.
Sources:
Miśkowiec, Pawel. “Name Game: The Naming History of the Chemical Elements: Part 2—Turbulent Nineteenth Century.” Foundations of Chemistry, 8 December 2022. DOI: 10.1007/s10698-022-09451-w.
Oxford English Dictionary, third edition, June 2010, s.v. rhodium, n.
Wollaston, William Hyde. “On a New Metal, Found in Crude Platina” (24 June 1804). Philosophical Transactions of the Royal Society of London, 94, 1804, 419–30 at 419. DOI: 10.1098/rstl.1804.0019.
Photo credit: Heinrich Pniok, 2009. Wikimedia Commons. Licensed under a Creative Commons Attribution-NonCommercial-NonDerivative 3.0 (US) license.