The new title compound, K3,44(NH4)0,56Se2Mo5O21.2H2O, has been synthesized in aqueous solution and characterized by elemental analysis, M.E.B, thermogravimetric analysis, I.R and single-crystal X-ray diffraction. It crystallizes in monoclinic system with P21/n space group. The parameters are a = 9,911(2) Å, b = 23,350(6) Å, c = 10,501(2) Å, β = 114,10(2)° and Z = 4. Its structure is characterized by the presence of the Standberg type clusters [Se2Mo5O21]4- linked to each other to a three dimensional network by monovalent cations K+ and NH4+ and water molecules.
I. Nagazi, R. Ben Smail, A. Haddad
selenomolybdate, polyoxometallate, heteropolyanion, Strandberg, crystal structure