TY - JOUR
T1 - Quartz-coesite transition revisited
T2 - reversed experimental determination at 500-1200°C and retrieved thermochemical properties
AU - Bose, K.
AU - Ganguly, J.
PY - 1995
Y1 - 1995
N2 - The quartz-coesite transition was determined by reversed experiments in a piston-cylinder apparatus in the range 500-1200°C. The equilibrium transition boundary can be expressed as P (kbar) = 21.945 (±0.1855) + 0.006901 (± 0.0003)T (K). It is subparallel to, but ~1.5 kbar higher than, the transition boundary determined by Bohlen and Boettcher (1982). The entropy [39.56 ± 0.2 J/(mol.K)] and enthalpy of formation (-907.25 ± 0.007 kJ/mol) were also retrieved from elements of coesite at 1 bar, 298 K, from phase-equilibrium data and selected thermochemical data from the literature. From the characteristics of the hysteresis loop it is concluded that the practice of maintaining a constant nominal pressure by repeated pressure adjustment during an experiment leads to variation of pressure on the sample. -from Authors
AB - The quartz-coesite transition was determined by reversed experiments in a piston-cylinder apparatus in the range 500-1200°C. The equilibrium transition boundary can be expressed as P (kbar) = 21.945 (±0.1855) + 0.006901 (± 0.0003)T (K). It is subparallel to, but ~1.5 kbar higher than, the transition boundary determined by Bohlen and Boettcher (1982). The entropy [39.56 ± 0.2 J/(mol.K)] and enthalpy of formation (-907.25 ± 0.007 kJ/mol) were also retrieved from elements of coesite at 1 bar, 298 K, from phase-equilibrium data and selected thermochemical data from the literature. From the characteristics of the hysteresis loop it is concluded that the practice of maintaining a constant nominal pressure by repeated pressure adjustment during an experiment leads to variation of pressure on the sample. -from Authors
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U2 - 10.2138/am-1995-3-404
DO - 10.2138/am-1995-3-404
M3 - Article
AN - SCOPUS:0028844909
SN - 0003-004X
VL - 80
SP - 231
EP - 238
JO - American Mineralogist
JF - American Mineralogist
IS - 3-4
ER -