Sc 2 (WO 4 ) 3 has been found to show the highly unusual property of negative thermal expansion over a temperature range of 10 to 1073 K. Powder neutron diffraction data from 10 to 450 K shows an essentially linear decrease in cell volume as a function of temperature. The intrinsic linear coefficien
Negative Thermal Expansion in Y2(WO4)3
โ Scribed by David A. Woodcock; Philip Lightfoot; Clemens Ritter
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 213 KB
- Volume
- 149
- Category
- Article
- ISSN
- 0022-4596
No coin nor oath required. For personal study only.
โฆ Synopsis
FIG. 1. Structure of Y (WO ) showing YO octahedra (white), W(1)O tetrahedra (light gray), and W(2)O tetrahedra (dark gray).
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Negative thermal expansion in the Sc 2 W 3 O 12 family has been pushed to much more pronounced values by substituting a large cation for Sc. X-ray diffraction measurements from 127 to 627ยฐยฐC give a linear thermal expansion coefficient of ุ 6.8ุ10 ุ6 /ยฐยฐC for Lu 2 W 3 O 12 compared to ุ2.2ุ10 ุ6 /ยฐยฐC
The structure of tetragonal NbOPO 4 has been studied from room temperature to 500ยฐยฐC by X-ray powder diffraction and to 327ยฐยฐC by neutron powder diffraction. Rietveld refinements were conducted on neutron data collected at 25, 100, 175, 200, 225, 275, and 327ยฐยฐC. A phase transition was found at abou