Thermal expansion of periclase (MgO) and tungsten (W) to melting temperatures

In situ x-ray data on molar volumes of periclase and tungsten have been collected over the temperature range from 300 K to melting. We determine the temperature by combining the technique of spectroradiometry try and electrical resistance wire heating. The thermal expansion (alpha) of periclase between 300 and 3100 K is given by alpha=2.6025 10(-5) + 1.3535 10(-8) T + 6.5687 10(-3)T(-1) - 1.8281 T-2. For tungsten, we have (300 to 3600 K alpha=7.86% 10(-6) + 6.392 10(-9) T. The data at 298 K for periclase is: molar volume 11.246 (0.031) cm(3), alpha=3.15 (0.07) 10(-5) K-1, and for tungsten: molar volume 9.55 cm(3), alpha=9.77 (10.08) 10(-6) K-1.