Thermal expansion and molar volume of MgO, periclase, from 5 to 2900 K
Reeber, Robert R.; Goessel, Kathryn; Wang, Kai
European Journal of Mineralogy Volume 7 Number 5 (1995), p. 1039 - 1048
published: Oct 5, 1995
manuscript accepted: Mar 21, 1995
manuscript received: Sep 1, 1994
ArtNo. ESP147050705001, Price: 29.00 €
Abstract Thermal expansion and molar volume of periclase are important parameters for thermodynamic modeling of the earth's interior. We have critically reviewed the available data and have found wide variations in the literature for MgO lattice parameters at room and high temperatures. Earlier Reeber (1975) developed an empirical quasi-harmonic model (QHM) that provides an excellent representation of thermal expansion from near 0 to 1200 K. Wang & Reeber (1995 a) show for alkali halides that above a temperature TL, the approximate temperature where all lattice modes are effectively excited, experimentally measured thermal expansion is slightly higher than an extrapolation of this empirical relationship. This difference is approximated with a 2nd order term that gives excellent quantitative agreement with experiment for alkali halides and cesium halides (Wang & Reeber, 1995 b) to approximately 90% of the melting temperature. The existing literature for periclase is evaluated within the constraints of the modified quasi-harmonic model (MQHM) and x-ray measurements at room temperature. At very high temperatures where experimental data is not available the MQHM provides a method to estimate high temperature thermal expansion. Our best estimate of the lattice parameter at 0 K is 4.20565 Å and at 298 K 4.21154 Å.