Synthesis and characterization of the layered vanadium borophosphate (imidazolium)3.8(H3O)1.2[(VO)4(BO)2(PO4)5].0.3H2O

The first layered vanadium borophosphate (imidazolium)3.8(H3O)1.2[(VO)4(BO)2(PO4)5].0.3H2O (1) has been synthesized hydrothermally and characterized by chemical analysis, infrared and Raman spectroscopy, and thermogravimetric and magnetic measurements. The compound crystallizes in the monoclinic space group C2/c, a = 9.4737 (5) A, b = 22.1444 (12) A, c = 17.2192 (13) A, beta = 105.936 (1) degrees, Z = 4. The structure contains a novel borophosphate secondary building unit, [B2P5O22], in which two BP2O10 trimers are linked by an additional PO4 tetrahedron. These units are connected by V(IV)2O8 dimers and V(IV)O5 square pyramids to form layers. The space between the layers is filled by disordered imidazolium and hydronium cations and water molecules that form a complex network of hydrogen bonds. A model for the interlayer disorder is proposed.