The synthesis of HAu(SeO4)(2) and MAu(SeO4)(2), where M is K, Rb or Cs
, is described. The synthesis of Au2O3 . 5.2H(2)O, as a starting subst
ance for double selenates, is presented also. The synthesized compound
s were investigated by chemical and thermal analysis. The chemical com
positions of the samples were confirmed and reactions of thermal decom
position were determined.