Synthesis and some properties of double chromates of praseodymium, neodymium, samarium with alkali metals

Some properties of the binary chromates MLn(CrO4)sub(2), where M=Na, K, Rb, Cs and Ln=Pr, Nd, Sm were synthesized and studied. Roentgenophase and densimetric analyses show that the compounds NaLn(CrO4)sub(2) (Ln=Pr, Nd, Sm) are isomorphous while KLn(CrO4)sub(2) (Ln=Pr,Nd,Sm) and RbLn(CrO4)sub(2) (Ln=Pr,Nd) are isostructural and crystallize in adifferent modification than sodium compounds. The compound RbSm(CrO4)sub(2) is excluded from this series. The binary cesium chromates are isostructural with CsLa(CrO4)sub(2) except of CsSm(CrO4)sub(2). The IR absorption spectra of the obtained binary chromates were considered. They correspond to the vibrations of highly distorted chromate groups