The pressure behavior of a cristobalite
نویسندگان
چکیده
Structural and volume compressibility data for two a cristobalite samples were determined by single-crystal X-ray diffraction methods at pressures up to -1.6 GPa. As with the other silica polymorphs that have been studied at high pressure, the change of the SiO-Si angle is correlated with the volume compressibility. The Si-O bond lengths and the O-Si-O angles remain essentially unchanged. The bulk modulus was determined to be 11.5(7) GPa with a pressure derivative of 9(2). Both crystals underwent reversible structural phase transitions in the pressure interval 1.18-1.60 GPa.
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