Three new phosphates, Cs8Pb4(P2O7)(4), CsLi7(P2O7)(2) and LiCa(PO3)(3): structural comparison, characterization and theoretical calculation

摘要

Through the high temperature solution method, three new phosphates, Cs8Pb4(P2O7)(4), CsLi7(P2O7)(2) and LiCa(PO3)(3), were obtained. X-ray diffraction analyses suggest that they crystallize in the space group P1 of the triclinic crystal system. However, the three-dimensional (3D) structures of Cs8Pb4(P2O7)(4) and CsLi7(P2O7)(2) consist of various isolated P2O7 groups, while LiCa(PO3)(3) is built up by the 1D (PO3)(infinity) chain. Detailed structural comparison suggests that the different sizes and coordination environments of Ca2+ and Zn2+ cations influence the whole structures of LiX(PO3)(3) (X = Ca and Zn). IR spectroscopy and UV/Vis/NIR diffuse reflectance spectroscopy analyses have been performed to investigate their optical properties. First-principles theoretical studies were also carried out to aid the understanding of electronic structures and linear optical properties.