ABSTRACT
Potassium cobalt hydrogenpyrophosphate dihydrate, KHCoP(2)O(7).2H(2)O, crystallizes in the orthorhombic space group Pnma. This salt is isotypic with KHMP(2)O(7).2H(2)O (M = Mn and Zn). The structure consists of alternating layers, built from HP(2)O(7)(3-) acidic pyrophosphate groups and CoO(6) octahedra, joined by potassium ions and bridging hydrogen bonds. The Co, K and water O atoms lie on mirror planes. The pyrophosphate group consists of two symmetry-related PO(4) groups, with the bridging O atom on a mirror plane.
ABSTRACT
The crystal structures of the isomorphous title compounds, namely potassium zinc hydrogen pyrophosphate dihydrate and potassium manganese hydrogen pyrophosphate dihydrate, consist of acidic pyrophosphate-metallate(II) layers joined by K(+) ions and hydrogen-bridging bonds. The Zn(2+)/Mn(2+) ions are octahedrally surrounded by four pyrophosphate O atoms and by two water molecules. The (HP(2)O(7))(3-) anions exhibit eclipsed conformations. The metal ions and water O atoms lie on mirror planes, as does the central O atom of the (HP(2)O(7))(3-) anion.
