Low temperature heat capacity of the high-pressure-phase of SiO2, coesite, and calculation of theα-quartz-to-coesite equilibrium boundary
✍ Scribed by Tooru Atake; Noriko Inoue; Hitoshi Kawaji; Ken-ichiro Matsuzaka; Masaki Akaogi
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 179 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0021-9614
No coin nor oath required. For personal study only.
✦ Synopsis
The high-pressure-phase of SiO 2 , coesite, was synthesized from α-quartz under high pressure using a multi-anvil apparatus, and the heat capacity was measured by adiabatic calorimetry between T = (13 and 300) K. The smoothed values of the heat capacity were obtained from the primary data, and the thermodynamic functions of coesite were calculated. The heat capacity, enthalpy, entropy, and Gibbs energy at T = 298.15 K were (45.12 ± 0.26) J • K -1
• mol -1 , (6.771 ± 0.045) kJ • mol -1 , (39.28 ± 0.27) J • K -1
• mol -1 , and (-4.939 ± 0.035) kJ • mol -1 , respectively. The results were compared with the values reported previously. The equilibrium boundary of the α-quartz-to-coesite transition was also calculated. The d p/dT slope of the boundary was about 5.8 • 10 -4 GPa • K -1 .