Synthesis methods for Ce(CrO4)2•xH2O and crystal structures of K2CrSO7, (NH4)2Cr2O7 and Na2Cr2O7•2H2O

New and quick methods to synthesize Ce(CrO4)(2)center dot 2H(2)O and Ce(CrO4)(2)center dot H2O, giving high yields, are described. The methods are based on exchange reactions by refluxing in water or on solid state reactions. The first crystal structure containing a chromatosulfato ion is presented. K2CrSO7 belongs to space group P2(1)/n with a = 7.4024(1), b = 7.3908(1), c = 12.9883(2) angstrom, beta = 90.021(1)degrees and Z = 4. The CrSO72- ion, consisting of one chromate group sharing one oxygen atom with one sulfate group, has a pseudo syn-C-2 nu conformation with eclipsed oxygen atoms. K2CrSO7 forms a three dimensional network of CrSO72- ions held together by the charge balancing potassium ions, with the general structural features common with dichromate-like structures. The redetermination of the structures of (NH4)(2)Cr2O7 (space group C2/c, with hydrogen atoms located) and Na2Cr2O7 center dot 2H(2)O (space group P2(1), with hydrogen atoms located and the absolute structure established) are reported.