Rhodium , hexaaqua complexes

Rhodium complexes with oxygen ligands, not nearly as numerous as those with amine and phosphine complexes, do, however, exist. A variety of compounds are known, iucluding [Rh(ox)3] [18307-26-1], [Rh(acac)3] [14284-92-5], the hexaaqua ion [Rh(OH2)3] [16920-31 -3], and Schiff base complexes. Soluble rhodium sulfate, Rh2(804 )3-a H2 0, exists iu a yellow form [15274-75-6], which probably coutaius [Rh(H20)3], and a red form [15274-78-9], which contains coordinated sulfate (125). The stmcture of the soluble nitrate [Rh(N03)3 2H20 [10139-58-9] is also complex (126). Another... 

Ru-O distances which are 212 pm in both complexes. For [Cp M(H20)3] (M = Rh, Ir) there is an even more dramatic increase of the water exchange rate constant (14 orders of magnitude) when compared with the corresponding hexaaqua-ion [M(H20)6p. This increase in reactivity is also related to a mechanistic changeover from an mechanism towards a more dissociative activation mode. In both cases the rhodium compound is significantly more reactive than the iridium one. 

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