Scandium tungstate above 2.5 GPa.
Synchrotron x-ray powder diffraction was used to study Sc{sub 2}W{sub 3}O{sub 12} in a diamond anvil cell up to 6.2 GPa in order to better characterize the second high pressure phase observed in earlier in-situ diffraction studies. Two crystalline-to-crystalline phase transitions were observed, in line with the earlier work. Above 2.7 GPa, Sc{sub 2}W{sub 3}O{sub 12} adopted a monoclinic structure with probable space group P2{sub 1}/n, that is distinct from the monoclinic phase existing between 0.3 GPa and 2.7 GPa. The bulk modulous (K{sub 0}) for this second high pressure phase was estimated to be 90(3) GPa using a Birch-Murnaghan equation of state with K{sub p} fixed at 4. Refining K{sub p} resulted in K{sub 0} = 72(3) GPa and K{sub p} = 12(1). The transition at {approx}2.7 GPa on compression involved a unit cell volume reduction of almost 18% and was not reversible on decompression to atmospheric pressure at ambient temperature, suggesting that changes in bonding occur at the phase transition. Linear compressibility values for this high pressure monoclinic phase were estimated to be {beta}{sub a} = 3.6(1) x 10{sup -3} GPa{sup -1}, {beta}{sub b} = 3.7(2) x 10{sup -3} GPa{sup -1}, {beta}{sub c} = 2.0(1) x 10{sup -3} GPa{sup -1} by straight line fits to the lattice constants over the range 0-6.2 GPa.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); National Science Foundation (NSF)
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 1004855
- Report Number(s):
- ANL/XSD/JA-63500; TRN: US1101019
- Journal Information:
- Solid State Commun., Vol. 148, Issue 11-12 ; Dec. 2008
- Country of Publication:
- United States
- Language:
- ENGLISH
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