Layered phosphonate salts of divalent metal ions (Mg, Mn, Zn, Ca, Cd) are precipitated by combining aqueous solutions of a phosphonic acid and a soluble metal salt. In this way compounds in the series M(O3CnH2n+1).H2O (M = Mg, Mn, Zn, = 1-12; M = Ca, Cd, = 1-4), M(O3PC6H5-H2O (M = Mg, Mn, Zn), Ca(HO3PC6H5)2, and Ca(HO3PCnH2n+1)2(n ≥ 5) were prepared. These compounds are insoluble in water at pH 7 but dissolve in dilute acid solutions. A preliminary X-ray structure for Mn(O3PC6H5).H2O, refined in the orthorhombic space group Pmn21with Z = 2 and a = 5.734 (5), b = 14.33 (3), and c = 4.945 (4) Å, is reported. The structure consists of layers of Mn atoms coordinated octahedrally by five phosphonate oxygen atoms and one water molecule. Each phosphonate group coordinates four Mn atoms, making a cross-linked Mn-O network. The phenyl groups lie above and below these approximately planar networks and make van der Waals contacts between layers. Compounds in the M(O3PCnH2n+1.H2O (= Mg, Mn, Zn) and M(O3PC6H5).H2O (M = Mg, Zn) series crystallize in Pmn21with a = 5.61-5.74 and c = 4.78-4.82 Å and with b varying according to the size of the alkyl or phenyl group. A structural model for these compounds is discussed.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry