Ammonium Rhodinitrite, (NH₄)₃Rh(NO₂)₆

Ammonium Rhodinitrite, (NH₄)₃Rh(NO₂)₆, is best obtained by adding ammonium chloride to a solution of the sodium salt. With warm hydrochloric acid it yields ammonium chlor-rhodite, (NH₄)₃RhCl₆.3H₂O.

The Barium Salt, Ba₃Rh₂(NO₂)₁₂.12H₂O, has also been prepared in an analogous manner to the sodium and potassium salts. It separates in somewhat bulky white crystals, which are soluble in water to the extent of one part in 50 of water at 16° C. and one part in 6.5 of water at the boiling-point. The crystals have no action on polarised light. With hydrochloric acid a mixture of barium and rhodium chlorides is obtained, and, by precipitating the barium with sulphuric acid, rhodium chloride can be obtained quite free from alkali chlorides.