Crystal Structures and Magnetic Properties of the New Alkaline Zinc Oxovanadium Phosphates MZn(H2O)(VO)2 (PO4)2(H2PO4) with M = K+, Rb+, and Cs+

New alkaline oxovanadium phosphates of composition MZn(H2O)(VO)2(PO4)2(H2PO4) (hereafter noted as MZnVPOʹs) were prepared hydrothermally for M+ = K+, Rb+, Cs+ that crystallize in the monoclinic symmetry. The compounds CsZnVPO and KZnVPO are isotypic (space group P21\m), whereas RbZnVPO shows a supercell (space group P21\n). All the three structures are based on linking of fused octahedra V2O9 with tetrahedra HxPO4 and ZnO3(H2O) with the counterbalancing alkaline ions located inside the voids of the three-dimensional framework [Zn(H2O)(VO)2(PO4)2(H2PO4)]-. Thermal analyses coupled with IR measurements support the structural results, and low-dimensional magnetism showing strong antiferromagnetic interactions is discussed.