IMPMC (UMR 7590, CNRS-Université Pierre et Marie Curie), Case Courrier 115, 4 place Jussieu, 75252 Paris Cedex 05, France.
Spectrochim Acta A Mol Biomol Spectrosc. 2014 Jan 3;117:406-12. doi: 10.1016/j.saa.2013.08.021. Epub 2013 Aug 15.
Co3(PO4)2, SrCo2(PO4)2, Co2P2O7, BaCoP2O7 and SrCoP2O7 present different geometries of five-coordinated Co(2+) (([5])Co(2+)) sites, coexisting with ([6])Co(2+) in Co3(PO4)2 and Co2P2O7, and ([4])Co(2+) in SrCo2(PO4)2. ([5])Co K-edge XANES spectra show that the intensity of the pre-edge and main-edge is intermediate between those of ([6])- and ([4])Co. Diffuse reflectance spectra show the contributions of Co(2+) in (D3h) symmetry for SrCo2(PO4)2, and (C4v) symmetry for BaCoP2O7 and SrCoP2O7. In Co3(PO4)2 and Co2P2O7 the multiple transitions observed arise from energy level splitting and may be labeled in (C2v) symmetry. Spectroscopic data confirm that (D3h) and (C4v) symmetries may be distinguished upon the intensity of the optical absorption bands and crystal field splitting values. We discuss the influence of the geometrical distortion and of the nature of the next nearest neighbors.
磷酸钴(II)、锶钴(II)磷酸二氢盐、磷酸二钴(II)磷氧化物、碳酸钡钴(II)磷氧化物和碳酸锶钴(II)磷氧化物呈现出五配位钴(II)（([5])Co(2+)）位点的不同几何构型，这些构型与 Co3(PO4)2 和 Co2P2O7 中的 ([6])Co(2+)和 SrCo2(PO4)2 中的 ([4])Co(2+)共存。([5])Co K 边 XANES 谱表明，前边缘和主边缘的强度介于 ([6])-和 ([4])Co 之间。漫反射光谱显示，SrCo2(PO4)2 中 Co(2+)具有(D3h)对称性的贡献，BaCoP2O7 和 SrCoP2O7 中 Co(2+)具有(C4v)对称性的贡献。在 Co3(PO4)2 和 Co2P2O7 中，观察到的多个跃迁源于能级分裂，可在(C2v)对称中标记。光谱数据证实，(D3h)和(C4v)对称性可通过光吸收带的强度和晶体场分裂值来区分。我们讨论了几何变形和最近邻性质的影响。
