화학공학소재연구정보센터
Inorganic Chemistry, Vol.39, No.3, 458-462, 2000
Synthesis and magnetic and transport properties of Sr6V9S22O2: "AM(2)S(5)" phases revisited
The compound Sr6V9S22O2 was prepared from SrS, sulfur, vanadium metal, and V2O5 at 950 degrees C in an evacuated quartz tube. The compound is rhombohedral, R (3) over bar, with a = 8.7538(6) Angstrom, c = 34.933(3) Angstrom, and Z = 3, and shows strong preferred orientation in its XRD profiles (00l) due to the layered nature of the structure. The compound contains charged CdI2 type VSI layers of formula [V7S14](4-) separated by [Sr-6(VOS3)(2)(S-2)](4+) layers. The latter has VOS33- tetrahedra and S-2(2-) disulfide units linked by Sr2+ ions. Magnetic susceptibility and four-probe resistivity studies show essentially temperature-independent paramagnetism above 80 K and small gap semiconductor behavior, respectively. The compound has a positive Hall coefficient at room temperature. The relationship among Sr6V9S22O2, "SrV2S5" (J. Solid State Chem. 1996, 126, 189), and other AM(2)S(5) phases is discussed.