Inner Sphere
[Co(NH3)5Cl]2+ + [Cr(H2O)6]2+ + 5H2O ? [Cr(H2O)5Cl]2+ + [Co(H2O)6]2+ + 5NH3
Cl- is transferred from Co to Cr
[Cr(H2O)5NC]2+ was prepared this way
[Co(NH3)5CN]2+ + [Cr(H2O)6]2++ 5H2O -fast-> [Cr(H2O)5NC]2+ + [Co(H2O)6]2+ + 5NH3
[Cr(H2O)5NC]2+ -30 sec-> [Cr(H2O)5CN]2+