INTERCALATION OF PYRIDINE INTO TERNARY TRANSITION-METAL DISULFIDES TA1-XMOXS2

Ternary phases Ta1-xMoxS2 with 0.25 less than or equal to x less than or equal to 0.55 have been investigated regarding their in tercalation potential using pyridine as guest molecule. Intercalation yields hexagonal phases Ta1-xMoxS2.(pyridine)(n). The different phases have been characterized by elemental analysis as well as TGA and powder diffraction patterns, which have been indexed using the space group P3m1. For the compound Ta0.65Mo0.35S2.(pyridine)(0.38) a structural model was developed, based on powder diffraction data: P3m1, a = 3.275(2), c = 12.008(7) Angstrom and Z = 1. During intercalation the stacking sequence of the host lattice is changed from BaB/AcA/CbC to BaB(pyr)/BaB(pyr), Intercalation of pyridine into Ta1-xMoxS2 proceeds via a two-step mechanism. In the first step orthorhombic phases are formed with reduced pyridine content as compared to the final intercalation product; e.g. Ta0.55Mo0.45S2.(pyridine)(0.38). The first step intercalation compounds can be obtained by interruption of the intercalation reaction after 7 days.