Sr3Cu3(PO4)4, Pb3Cu3(PO4)4, BaCu2(PO4)2.H2O, AND Ba2Cu(PO4)2.H2O: CRYSTAL STRUCTURES AND TOPOLOGICAL RELATIONSHIPS

摘要

The four Cu(II)-phosphates(V) Sr3Cu3(PO4)4, Pb3Cu3(PO4)4, BaCu2(PO4)2.H2O, and Ba2Cu(PO4)2.H2O were synthesized under hydrothermal conditions. Their structures were determined from single-crystal XRD data. They are related to a group of compounds formed by Cu(II)-PO4/AsO4 layers linked by Me atoms with large ionic radii like alkali, alkaline earth, Pb(II), or Ag(I), and partly by H bonds. The layers are formed by Cu3O12 units: one square-planar coordinated Cu atom with -1 symmetry is corner connected to two Cu atoms in a [4+1] or [5] coordination. Distinct patterns and links of the Cu3O12 groups by PO4 tetrahedra were observed, AA and AB stacking variants of the layers occur. Ba2Cu(PO4)2.H2O features isolated CuO4 squares interconnected by PO4 tetrahedra to chains which represent a component of the layers found in the other compounds. 14 refs.