Intensely reflective, fairly inert precious metal. m.p. 1966±3 ºC; 3571±5.5 ºF b.p. 3727±100 ºC; 6741±180 ºF density 12.41 g/cc; 774.73 pound/cubic foot	memory peg
	1803/04 William Hyde Wollaston, England
	Ροδον (rodon) = Rose (Greek)

Shortly after Palladium (1802), Rhodium was discovered in 1804 in crude Platinum from South America by the English chemist William Hyde Wollaston (1766-1828) (note).. From his sample crude Platinum he removed the Platinum and Palladium and was left with a dark red powder. This proved to be the double chloride of sodium and a new metal. That salt would today be known as sodium rhodium chloride (Na₃RhCl₆.12H₂O). This salt was heated up with Hydrogen and was washed with water to remove the sodium chloride. The resulting residue was rhodium powder.

Due to the colour of the chloride RhC_l3 and of the respective aqueous solutions, Wollaston chose the name rhodium, after the Greek Ροδον [rodon] = rose (colour of a rose):

Although in undated notebooks Wollaston refers to it as "N-nov^m" (perhaps Novum). He published details of this discovery immediately after its isolation; apparently he had no desire to initiate a second dispute, as with Palladium.

Wollaston's notebook. Fragment from the entry for 14 June 1804, when he named Rhodium.

• Griffith, W.P., Bicentenary of Four Platinum Group Metals, Part I: Rhodium and Palladium – events surrounding their discoveries. In: Platinum Metals Review 47, 4 (October 2003): 175-183 (on-line).
• International Platinum Association, Rhodium History (on-line).
• Platinum. Gmelins Handbuch der anorganische Chemie, 8. Aufl.; System-Nummer 68 (1951), Pt. A. pp. 11-12.
• Robertson Research Int'l Ltd., Dr. Rob's Chem4all, Quote of the week
• Usselman, Melvyn, "A secret history of platinum". Chembytes e-zine, December 2001 (on-line).
• Weeks, Mary Elvira, Discovery of the Elements, comp. rev. by Heny M. Leicester (Easton, Pa.: Journal of Chemical Education, 1968), pp. 410-418.