^1,2Tingting Gu, ^1,2Yingwei Fei, ¹Xiang Wu, ¹Shan Qin
¹Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, Peking University & School of Earth and Space Sciences, Peking University, Beijing 100871, China
²Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C., 20015, U.S.A

Fe-S-P compounds have been observed in many meteorites and could be the important components in planetary cores. Here we investigated the phase stability of Fe3(S,P) solid solutions and synthesized high-quality Fe3(S1−xPx) high-pressure phases in the multi-anvil press. The physical properties of Fe3(S0.5P0.5) were further studied in the diamond-anvil cell by synchrotron X-ray diffraction and emission spectroscopy. The solubility of S in the Fe3(S,P) solid solution increases with increasing pressure. The minimum pressure to synthesize the pure Fe3S and Fe3(S0.13P0.87) is about 21 and 8 GPa, respectively. The observed discontinuity in unit-cell parameters at about 18 GPa is caused by the high-spin to low-spin transition of iron, supported by X-ray emission spectroscopy data. The sulfur solubility in Fe3(S,P) solid solutions could be an excellent pressure indicator if such solid solutions are found in nature.

Reference
Gu T, Fei Y, Wu X, Qin S (2016) Phase stabilities and spin transitions of Fe3(S1−xPx) at high pressure and its implications in meteorites. American Mineralogist 101, 205-210
Link to Article [doi:10.2138/am-2016-5466]
Copyright: The Mineralogical Society of America