Vanadium subgroup

Nickolaev, V.P. (1983). "Crystal Chemistry of Phosphates with Metals of Vanadium Subgroup". Ph.D. Thesis. Inst, of Inorg. Chem., Acad. Sci. USSR, Moscow (in Russian). 

The first metal-olefin complex was reported in 1827 by Zeise, but, until a few years ago, only palladium(II), platinum(Il), copper(I), silver(I), and mercury(II) were known to form such complexes (67, 188) and the nature of the bonding was not satisfactorily explained until 1951. However, recent work has shown that complexes of unsaturated hydrocarbons with metals of the vanadium, chromium, manganese, iron, and cobalt subgroups can be prepared when the metals are stabilized in a low-valent state by ligands such as carbon monoxide and the cyclopentadienyl anion. The wide variety of hydrocarbons which form complexes includes olefins, conjugated and nonconjugated polyolefins, cyclic polyolefins, and acetylenes. 

Vanadium, the first element in Subgroup oA, and neighbour to chromium, is found in association with molybdenum in certain complex compounds. For example, when boiling solutions of molybdo-oxalates react with vanadium pentoxide, crystalline products are obtained which are thought to be substituted vanadates containing the complex anion... 

Vanadium compounds with oligodentate ON and ONS ligands. Each of the vanadium complexes represents an example of a specific subgroup. 33, dioxo—V, square pyramidal (sqp) 34, monooxo-sqp 35, monooxo-V, trigonal bipyramidal 36, dioxo-V, octahedral (oct) 37, monooxo-V, oct 38, monooxo-V, oct/sqp 39, monooxo-V, sqp 40, monooxo-V, oct. In the mixed-valence dinuclear complexes 41 and 42, the two vanadium centres are indistinguishable (41) and isolated (42), respectively. 

The iso- and hetero-polyanions of the vanadium and chromium subgroups have been the part-subjects of several monographs in recent years (1, 2, 3). Good accounts have been given of their structural chem-... 

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