Skip to main content
U.S. flag

An official website of the United States government

The thermal expansion of anhydrite to 1000° C

January 1, 1979

The thermal expansion of anhydrite, CaSO4, has been measured from 22° to 1,000° C by X-ray diffraction, using the Guinier-Lenné heating powder camera. The heating patterns were calibrated with Guinier-Hägg patterns at 25° C, using quartz as internal standard. Heating experiments were run on natural anhydrite (Bancroft, Ontario), which at room temperature has lattice constants in close agreement with those of synthetic material. The orthorhombic unit cell at 22° C (space groupAmma) has a=7.003 (1) Å, b=6.996 (2) Å and c=6.242 (1) Å, V=305.9 (2) Å3. At room temperature, the thermal expansion coefficients α and β (α in °C−1×104, β in °C−2×108) are for a, 0.10, −0.69; forb, 0.08, 0.19; for c, 0.18, 1.60; for V, 0.37, 1.14. Second-order coefficients provide an excellent fit over the whole range to 1,000° C.

Publication Year 1979
Title The thermal expansion of anhydrite to 1000° C
DOI 10.1007/BF00308361
Authors Howard T. Evans
Publication Type Article
Publication Subtype Journal Article
Series Title Physics and Chemistry of Minerals
Index ID 70012470
Record Source USGS Publications Warehouse