VISIBLE AND ULTRAVIOLET ABSORPTION SPECTRA OF RHODIUM(III) IN FUSED ALKALI CHLORIDES AND NITRATES

Abstract

The spectrum of RhCl3 in fused LiCl–KCl at 440 °C is sufficiently different from that of RhCl63− to suggest the existence of some other species such as dimeric or polymeric bridge-complexes, or, less likely, tetrahedral RhCl4−. The spectra of RhCl3 and K3Rh(NO2)6 in fused NaNO3–KNO3 at 300 °C indicate the occurrence of nitro coordination in both systems, probably completely in the latter case, but in competition with chloro coordination in the former. Addition of KCl to a solution of RhCl3 in NaNO3–KNO3 causes spectral changes which suggest that RhCl63− is the principal rhodium species present.