A novel ehtylenediamine templated open- framework vanadium phosphate (H3NCH2CH2NH3)3- [ (VO)4(PO4)2(HPO4)4 has been hydrothemally synthesized and characterized by single-crystal X-ray diffraction. Green needle- like compound crystallized in monoclinic space group C2/c with a=1.8505(9) nm,b=0.7089(4) nm, c=2.3304(10) nm, β=96.43 (3)°, V-3.038(3) nm^3,Z=8, R=0.067 for 1912 unique reflections, The structure consists of layers constructed of corner- sharing V(Ⅳ) octahedra, V( Ⅳ) trigonal bipyramids, (PO4)^3- and (HPO4)^2- tetrahedra, which are held together by hydrogen bonding interaction to form the tunnels paralleled to the c axis and the (110) direction. Studies of crystal structure and crystal chemistry shows that this compound is a new VPO phase with an unique and topotactic two dimensional open framework structure.

Key words: PHOSPHATE, VANADIUM COMPOUNDS, VANADYL COMPLEX, HOLE CHANNELS, CRYSTAL STRUCTURE, HYDRO-THERMAL METHOD, FORMWORK, STRUCTURE CHARACTERISTICS