Cation preferences in thio-olivines (Fe1-xMnx)(2)SiS4, x <= 0.50, studied by Mossbauer spectroscopy at room temperature

Synthetic (Fe1-xMnx)(2)SiS4, Mn = 0, 0.01, 0.02, 0.05, 0.10, 0.20, 0.50, wi th olivine structure, Pnma, has been synthesized using quartz-ampoule techn iques. The powder materials have been characterized, using X-ray diffractio n (XRD) and Mossbauer spectroscopy. The cell parameters, a, b, c and V incr ease with x. Paramagnetic Mossbauer patterns recorded at room temperature c an be decomposed into two doublets. The doublet showing lower centroid shif t and higher absolute value of the quadrupole splitting is assigned to iron at M1 sites. Iron is enriched in M1 and the distribution coefficient K-d = 4.7(4). Obtained cation partitioning is compared with literature results f or thiogermanates and oxyolivines.