Thermal decomposition of rhodium(III) chloride under inert, oxidative and reductive gas atmospheres was investigated in order
to determine its thermal properties. Stoichiometries of the reactions occurring during heating are described. it is suggested
that the chemical formula of soluble rhodium(III) chloride should be presented as RhCl3HCLxH2O. Cold crystallisation of anhydrous rhodium(III) chloride at a temperature of about 500C was established. The procedure
for quantitative determination of volatile matter (water and hydrochloric acid) content and rhodium content by thermogravimetry
is given and discussed. The repeatability and reproducibility of the method are estimated.