Preparation and crystal structures of Cu2HfS3

The phase relations of the compound Cu2HfS3 have been studied by XRD and DS C methods. The following three types were found to exist in the temperature range from 500 to 1300 degreesC: (a) monoclinic alpha -Cu2HfS3 phase with a=12.271(3) Angstrom, b=11.162(3) Angstrom, c=6.429(2) Angstrom, beta =100. 04(2)degrees below 650 degreesC, (b) monoclinic beta -Cu2HfS3 phase with a= 9.611(2) Angstrom, b=6.444(1) Angstrom, c=7.127(3) Angstrom, beta =98.05(2) degrees in the temperature range of 650-780 degreesC, and (c) trigonal gamm a -Cu2HfS3 phase with a=6.456 Angstrom and c=12.188 Angstrom above 787 degr eesC. Structure determination of beta -Cu2HfS3 phase was attempted using th e Rietveld method. Electrical resistivity measurements were carried out for the trigonal gamma -Cu2HfS3 phase. (C) 2001 Elsevier Science B.V. FLU righ ts reserved.