Metallurgical and physical properties of ternary Molybdenum Sulfides (MxMo3S4) as synthetized in the bulk state

The compounds M
x
Mo
6
X
8
(M=Pb, Sn, Cu, x =S, Se) crystallizing in the rhombohedral Chevrel phase have been prepared by melting under a pressure of 100 bars of argon and temperatures above 1700°C . The variation of the superconducting transition temperature as a function of the concentration x was studied in the systems Cu
x
Mo
6
S
8
and Cu
x
Mo
6
Se
8
. The microscope observation of these compounds leads to the conclusion that the phase forms congruently. Large single crystals have been prepared. The temperature at which the rhombohedral phase transforms to the orthorhombic structure decreases strongly if the Cu content increases.