Rhodium is a very expensive precious metal, whose major use is in catalytic convertors, as it is very good at reducing levels of nitrogen oxides.
The metal is used in mirrors and optical fibres, and as it is very shiny it is sometimes used as a coating for jewellery made from cheaper metals.
Rhodium turns up in lip balm, cough remedies, toothpaste and aftershave, because rhodium catalysts are used to make synthetic menthol flavours, says Professor Allan Blackman from the Auckland University of Technology, in episode 69 of Elemental.
The Elemental podcast is celebrating 150 years since the periodic table was first published by Russian chemist Dmitri Mendeleev.
Find out more about events during the United Nation’s International Year of the Periodic Table.
Professor Allan Blackman is at Auckland University of Technology.