FACILE SYNTHESIS OF PSEUDO ONE-MONODIMENSIONAL TERNARY MOLYBDENUM CHALCOGENIDES M2Mo6X6 (X equals Se, Te; M equals Li, Na. . Ca).

Article abstract of DOI:10.1016/0025-5408(84)90054-0

High-temperature solid-state reactions (1100 degree C) are generally used to prepare members of this class, such as In//2Mo//6Se//6. This paper describes ion exchange reactions of In//2Mo//6X//6 with alkali iodide and chloride salts at 550 degree C to give M//2Mo//6X//6 and mixed solid solutions In//2// minus //xM//xMo//6X//6 (M equals Li, Na, K, Rb, Ca; X equals Se, Te). Furthermore, it is shown that ion exchange provides a low-temperature route to prepare phases which are not stable at high temperature, such as In//2// minus //xM//xMo//6Se//6 0 less than equivalent to x less than equivalent to 2 and M equals alkali. When M equals Li, the lithium can be partially removed by oxidation with iodine, producing nonstoichiometric ternary molybdenum chalcogenides In//2// minus //xMo//6Se//6 (0 less than equivalent to x less than equivalent to 1. 8). Superconducting measurements indicate that only Tl//2Mo//6Se//6 is superconducting above 1K.