Review on vanadium phosphates with mono and divalent metallic cations: syntheses, structural relationships and classification, properties

The vanadium phosphates with mono or divalent metallic cations (with A=Li, Na, K, Rb, Cs, Ag, Tl, Ca, Sr, Ba, Cd, Co, Cu, Hg, Mn, Ni, Ph, Zn) form a huge family of compounds with complicated structures. In this review 126 phosphates are included with their synthetic and structural characteristics. More particularly the environment of the vanadium atom, the connections of the vanadium polyhedra and the connections with the phosphates groups into VxOy and VxPyOz units and chains are discussed. A classification based on the connection of the vanadium polyhedra is proposed. One can observe that the vanadium atom adopts octahedral, square pyramidal, trigonal bipyramidal and tetrahedral coordinations. The trivalent, tetravalent and pentavalent vanadium are generally characterized by zero, one and two short V-O distances, respectively, in these compounds. The vanadium polyhedra are either isolated or connected into VxOy units (with 2 less than or equal tox less than or equal to9) or connected into infinite chains. The arrangements of the vanadium, phosphorus and A cations are noted according to the A, V and P ratios. The magnetic and catalytic properties of 45 and 15 compounds, respectively, are reviewed and their structures-properties relationships are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.