English chemist William H. Wollaston discovered rhodium in 1803 while he was experimenting on a platinum ore in Peru. Hippolyte- Victor Collet- Descotils alerted Wollaston about the chance of a new element as he believed that the red colour of some platinum salts was due to the presence of an unidentified metal.
To find out this new metal, Wollaston, dissolved crude platinum in aqua regia, which is a concentrated solution of hydrochloric and nitric acids. After that he precipitated platinum by dissolving the solution in ammonium chloride. But there was no new element.
Further experiments produced a deep red powder, sodium rhodium chloride. When this compound was treated with zinc, it gave a black and flaky precipitate of rhodium. Wollaston named the element rhodium based on the Greek word ‘rhodon’, which means rose.
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