TY - JOUR
T1 - The quartz-coesite-stishovite transformations
T2 - new calorimetric measurements and calculation of phase diagrams
AU - Akaogi, Masaki
AU - Navrotsky, Alexandra
N1 - Funding Information:
We are very grateful to E. Ito (Okayama University) for his permission to use the apparatus for the synthesis of stishovite, and to J. Susaki (University of Tokyo) for his synthesis of coesite. This work was supported by National Science Foundation Grant DMR8106027.
PY - 1984/12/1
Y1 - 1984/12/1
N2 - High temperature solution calorimetry of synthetic quartz, coesite and stishovite provides enthalpies of transition. ΔH9750 for quartz-coesite and ΔH2980 for coesite-stishovite transition are 320 ± 70 and 11700 ± 410 cal mol-1, respectively. The present transformation enthalpy data represent a small but significant revision of those of Holm et al. Using the published phase equilibrium data, thermal expansivity, compressibility and heat capacity data, ΔS9750 for the quartz-coesite and ΔS2980 for the coesite-stishovite transition are -1.2 ± 0.1 and -1.0 ± 0.4 cal K-1 mol-1, respectively. These thermochemical data are used to calculate phase boundaries of the transitions. The calculated quartz-coesite transition boundary agrees well with the one determined experimentally by Bohlen and Boettcher. The calculated coesite-stishovite boundary is generally consistent with data by Yagi and Akimoto and by Suito.
AB - High temperature solution calorimetry of synthetic quartz, coesite and stishovite provides enthalpies of transition. ΔH9750 for quartz-coesite and ΔH2980 for coesite-stishovite transition are 320 ± 70 and 11700 ± 410 cal mol-1, respectively. The present transformation enthalpy data represent a small but significant revision of those of Holm et al. Using the published phase equilibrium data, thermal expansivity, compressibility and heat capacity data, ΔS9750 for the quartz-coesite and ΔS2980 for the coesite-stishovite transition are -1.2 ± 0.1 and -1.0 ± 0.4 cal K-1 mol-1, respectively. These thermochemical data are used to calculate phase boundaries of the transitions. The calculated quartz-coesite transition boundary agrees well with the one determined experimentally by Bohlen and Boettcher. The calculated coesite-stishovite boundary is generally consistent with data by Yagi and Akimoto and by Suito.
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U2 - 10.1016/0031-9201(84)90013-X
DO - 10.1016/0031-9201(84)90013-X
M3 - Article
AN - SCOPUS:0021561117
SN - 0031-9201
VL - 36
SP - 124
EP - 134
JO - Physics of the Earth and Planetary Interiors
JF - Physics of the Earth and Planetary Interiors
IS - 2
ER -