RuCl63

RuCl63, written as [RuCl6]3-, is the hexachlororuthenate(III) anion. It is an octahedral coordination complex of ruthenium in the +3 oxidation state, surrounded by six chloride ligands. In solution, the complex typically adopts Oh symmetry with Ru–Cl bonds characteristic of ruthenium(III) chlorido complexes.

Because chloride is a weak-field ligand, [RuCl6]3- is generally high-spin, corresponding to a d5 electron configuration on Ru(III). The complex is paramagnetic, with magnetic properties reflecting the five unpaired electrons. Its color and electronic spectrum arise from ligand-field transitions that are typical of octahedral ruthenium(III) chlorido species.

Preparation and occurrence: In strongly chloride-rich media, ruthenium trichloride or related ruthenium(III) salts can be converted into [RuCl6]3- and its salts. It is commonly isolated as salts such as K3[RuCl6], Na3[RuCl6], or (NH4)3[RuCl6], which are water-soluble. The anion is primarily encountered in inorganic synthesis and coordination chemistry rather than as a bulk solid or naturally occurring mineral.

Chemical properties: The six chloride ligands make the complex relatively stable in chloride solutions but allow for ligand substitution under appropriate conditions. The complex can be reduced to Ru(II) species in redox processes and can serve as a reactive precursor for the preparation of a wide range of ruthenium(III) and ruthenium(II) complexes.

Applications: [RuCl6]3- serves as a versatile starting material in inorganic synthesis, enabling the preparation of various ruthenium chlorido complexes and catalysts through ligand substitution and redox chemistry.

See also: hexachlororuthenate(III), ruthenium chloride, coordination chemistry.