TANG Jun-jie1,2, LIU Xi1,2, XIONG Zhi-hua1,2, HE Qiang1,2, SEAN R. Shieh3, WANG He-jin1,2
1. Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, Peking University, Beijing 100871, China;
2. School of Earth and Space Sciences, Peking University, Beijing 100871, China;
3. Department of Earth Sciences, University of Western Ontario, London, Ontario, N6A 5B7, Canada
Abstract: Euclase samples collected from Jiangxi, China, were studied using high temperature X-ray diffraction, DSC-TGA analysis, polarized FTIR and high pressure Raman. High temperature X-ray diffraction data suggested that euclase becomes fully amorphous at ~1273 K (ambient pressure), and its volumetric thermal expansion coefficient is αV = 1.2(1) × 10-5 + 0.16(1)T × 10-9/K (temperature range of 298-1223 K). The DSC-TGA data suggested that euclase starts to break down at 750 K and reaches the maximum reaction rate at 1266 K. The polarized FTIR data collected in the (010) plane of euclase indicated that the absorbance of OH- is strongest when the angle between the IR polarizer and c-axis of euclase is 70°or 250° and is weakest when 160° or 340° which suggested that the orientation of the OH- dipole parallels to the former direction. High pressure Raman data collected with a diamond-anvil cell at room temperature suggested no phase transition occurs as pressure increasing up to 12.3 GPa. Based on the high pressure Raman data, the calculated average mode Grüneisen parameter and thermal Grüneisen parameter of euclase are 0.52(2) and 0.64(2), respectively. Alternatively, the calculated thermal Grüneisen parameter from Grüneisen equation for euclase is 0.70(6).
Keywords: euclase high temperature X-ray diffraction high-p Raman spectroscopy polarized FTIR spectroscopy Grü neisen parameter
