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 h uge family of compounds with complicated structures. In this review 126 pho sphates are included with their synthetic and structural characteristics. M ore particularly the environment of the vanadium atom, the connections of t he vanadium polyhedra and the connections with the phosphates groups into V xOy and VxPyOz units and chains are discussed. A classification based on th e connection of the vanadium polyhedra is proposed. One can observe that th e vanadium atom adopts octahedral, square pyramidal, trigonal bipyramidal a nd tetrahedral coordinations. The trivalent, tetravalent and pentavalent va nadium are generally characterized by zero, one and two short V-O distances , respectively, in these compounds. The vanadium polyhedra are either isola ted or connected into VxOy units (with 2 less than or equal tox less than o r equal to9) or connected into infinite chains. The arrangements of the van adium, phosphorus and A cations are noted according to the A, V and P ratio s. The magnetic and catalytic properties of 45 and 15 compounds, respective ly, are reviewed and their structures-properties relationships are discusse d. (C) 2000 Elsevier Science Ltd. All rights reserved.