Crystals of two polymorphs of CsCuPO4 have been obtained by high-temperature reaction of CsNO3, Cu2(NO3)2 and (NH4)4P2O7. The structures of both polymorphs were solved using single crystal X-ray diff raction. α-CsCuPO4 is orthorhombic, space group Cmcm, a = 7,0176(10), b = 6,8494(5), c = 22,691(2) A, V = 1064,1(4) A3, R1 = 0,116 for 782 unique reflections [I > 2s(I)]. The structure is based upon anionic layers [Cu(PO4)]-, with Cs+ ions in between. β-CsCuPO4 is orthorhombic as well, space group Pm21n, a = 5,3362(9), b = 8,8712(20), c = 8,967(18) A, V = 422,58(15) A3, R1 = 0,096 for 1191 unique reflections [I > 2s(I)]. The structure consists of the [Cu(PO4)]-framework of the ABW topology formed by corner sharing of [PO4] and [Cu2+O4] tetrahedra. Cs+ ions reside in framework cavities. Comparative study of complexity parameters and molar volumes of the two phases demonstrates that the layered α-phase is a high-temperature modification, whereas the β-phase is a low-temperature modification. Refs 22. Tables 6.

Original languageEnglish
Pages (from-to)49-57
Number of pages9
Issue number3
StatePublished - Sep 2015

    Scopus subject areas

  • Geology
  • Earth and Planetary Sciences(all)

    Research areas

  • Cesium, Complexity, Copper, Crystal structure, Phosphates, Polymorphism, Radionuclides

ID: 35996635