THERMAL-EXPANSION OF CUMOO4 BELOW ROOM-TEMPERATURE

Structure data for both triclinic alpha- and gamma-CuMoO4 have been de livered with anisotropic temperature factors at 190 K. The complete te nsors of linear thermal expansion coefficients were derived for alpha- and gamma-CuMoO4 using the temperature dependence of lattice paramete rs within the temperature range 20 K-300 K and 20 K-260 K, respectivel y. The orientation of principal axes and values of principal expansion coefficients are given for selected temperatures. Their relation to t he structure is discussed. The volume expansion coefficient of a CuMoO 4 becomes negative below 80 K.