Crystal Structures of New Chalcogenide- Containing Yttrium Orthosilicates Y 2 SiO 4 Q (Q = S, Se)

Compounds Y 2 SiO 4 Q (Q = S, Se) are obtained by the interaction of oxides and elemental substances in cesium chloride flux. The structures of these compounds are determined by the single crystal XRD analysis. These compounds isostructural and crystallize in the space group Pbcm with the following parameters: Y 2 SiO 4 S ( I ) a = 6.0462(8) Å, b = 6.8976(9) Å, c = 10.6558(13) Å, V = 444.39(10) Å 3 ; Y 2 SiO 4 Se ( II ) a = 5.9935(7) Å, b = 6.9216(8) Å, c = 10.7688(12) Å, V = 446.74(9) Å 3 . The measured fluxing points are 1650±15 °С for I and 1850±15 °С for II .