Moseley Duncan H, Juneja Rinkle, Daemen Luke L, Sergueev Ilya, Steinbrügge René, Leupold Olaf, Cheng Yongqiang, Cooper Valentino R, Lindsay Lucas, Kidder Michelle K, Manley Michael E, Hermann Raphaël P
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
Inorg Chem. 2023 Oct 9;62(40):16464-16474. doi: 10.1021/acs.inorgchem.3c02189. Epub 2023 Sep 25.
α-SbO (cervantite) and β-SbO (clinocervantite) are mixed valence compounds with equal proportions of Sb and Sb as represented in the formula SbSbO. Their structure and properties can be difficult to calculate owing to the Sb lone-pair electrons. Here, we present a study of the lattice dynamics and vibrational properties using a combination of inelastic neutron scattering, Mössbauer spectroscopy, nuclear inelastic scattering, and density functional theory (DFT) calculations. DFT calculations that account for lone-pair electrons match the experimental densities of phonon states. Mössbauer spectroscopy reveals the β phase to be significantly harder than the α phase. Calculations with O vacancies reveal the possibility for nonstoichiometric proportions of Sb and Sb in both phases. An open question is what drives the stability of the α phase over the β phase, as the latter shows pronounced kinetic stability and lower symmetry despite being in the high-temperature phase. Since the vibrational entropy difference is small, it is unlikely to stabilize the α phase. Our results suggest that the α phase is more stable only because the material is not fully stoichiometric.
α-SbO（黄锑矿）和β-SbO（斜方黄锑矿）是混合价化合物，其中Sb³⁺和Sb⁵⁺的比例相等，化学式为Sb³⁺Sb⁵⁺O₄。由于Sb的孤对电子，它们的结构和性质可能难以计算。在这里，我们结合非弹性中子散射、穆斯堡尔光谱、核非弹性散射和密度泛函理论（DFT）计算，对晶格动力学和振动性质进行了研究。考虑孤对电子的DFT计算与声子态的实验密度相匹配。穆斯堡尔光谱显示β相比α相硬得多。对氧空位的计算揭示了两个相中Sb³⁺和Sb⁵⁺非化学计量比例的可能性。一个悬而未决的问题是，是什么导致α相比β相更稳定，因为后者尽管处于高温相，但显示出明显的动力学稳定性和较低的对称性。由于振动熵差很小，不太可能使α相稳定。我们的结果表明，α相更稳定仅仅是因为材料不是完全化学计量的。
