The structure of the salt [Lambda-Co(en)(3)][Delta-Co(edta)]Cl-2.10H(2)O has been determined by X-ray crystallography. The salt crystallizes in the orthorhombic space group P2(1)2(1)2 (No. 18) with Z = 2, a = 21.046(3) Angstrom, b = 12.813(2) Angstrom, c = 8.158(1) Angstrom, and R = 0.035 fbr 5263 reflections. The complex ions participate in a network of hydrogen bonds which is interpreted to suggest a mechanism for chiral discrimination. Outer-sphere reduction of [Co(edta)](-) by [Ru(en)(3)](2+) takes place with a second-order rate constant of 6 x 10(3) M(-1) s(-1) at 25 degrees C and 0.10 M ionic strength. Chiral induction in the reaction results in a 2% enantiomeric excess with a Delta Lambda preference, significantly smaller than the 10% Delta Lambda induction found with [Co(en)(3)](2+) as reductant. This difference in chiral induction between the two reductants is ascribed to differences in chiral recognition in the assembly of electron-transfer precursor complexes.