The ternary yttrium sulfides, CaY{sub 2}S{sub 4}, and BaY{sub 2}S{sub 4}: Structures and properties
- Naval Air Warfare Center, China Lake, CA (United States)
- Connecticut College, New London, CT (United States)
X-ray single-crystal structure determinations have confirmed that CaY{sub 2}S{sub 4} crystallizes in the orthorhombic [Yb{sub 3}S{sub 4}]-type structure whereas SrY{sub 2}S{sub 4} and BaY{sub 2}S{sub 4} adopt the orthorhombic [CaFe{sub 2}O{sub 4}] structure. Both structure types feature three-dimensional frameworks build of edge- and corner-sharing [YS{sub 6}] octahedra. CaY{sub 2}S{sub 4}, in space group Pnma, has cell dimensions a = 12.953(3) {angstrom}, b = 3.8835(5) {angstrom}, c = 13.081(3) {angstrom}, Vol = 658.0(2) {angstrom}{sup 3}, Z = 4, and D{sub x} = 3.494 g/cm{sup 3} (M{sub f} = 346.1). SrY{sub 2}S{sub 4}, in Pmnb, has a = 3.9775(6), b = 11.974(2), c = 14.294(2) {angstrom}, Vol = 680.8(2) {angstrom}{sup 3}, Z = 4, and D{sub x} = 3.841 g/cm{sup 3} for M{sub F} = 393.7; BaY{sub 2}S{sub 4}, in Pmnb, has a = 4.0263(2), b = 12.2134(8), c = 14.484(1) {angstrom}, Vol = 712.23(9) {angstrom}{sup 3}, Z = 4, and D{sub x} = 4.135 g/cm{sup 3} for M{sub f} = 443.4. Room temperature X-ray powder diffraction data for all three compounds and high-temperature unit cells for CaY{sub 2}S{sub 4} are also reported. The overall average linear thermal expansion of CaY{sub 2}S{sub 4}f are also reported. The overall average linear thermal expansion of CaY{sub 2}S{sub 4} upon heating was found to be approximately 11.9 x 10{sup {minus}6}/{degrees}K as compared to that of 7.2 x 10{sup {minus}6}{degrees}K found for ZnS. The onset oxidative decomposition temperatures for CaY{sub 2}S{sub 4}, SrY{sub 2}S{sub 4}, and BaY{sub 2}S{sub 4} were observed to be 545, 565, and 590{degrees}C, respectively, as compared to 530{degrees}C for ZnS. The properties of these compounds indicate that they are potentially useful as infrared window materials.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 146441
- Journal Information:
- Journal of Solid State Chemistry, Vol. 117, Issue 2; Other Information: PBD: Jul 1995
- Country of Publication:
- United States
- Language:
- English
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