Wikipedia
Dichlorobis(ethylenediamine)nickel(II)
Dichlorobis(ethylenediamine)nickel(II) is the coordination compound with the formula NiCl(en), where en = ethylenediamine. This blue solid is soluble in water and polar organic solvents. The complex is neutral. It is available in both the anhydrous and the monohydrated forms. The preparation of NiCl(en) entails treating nickel chloride solutions with ethylenediamine. Crystalline material is prepared by ligand redistribution from [Ni(en)]Cl2HO and hydrated nickel chloride:
2 [Ni(en)]Cl + NiCl → 3 NiCl(en)The rapid ligand redistribution is indicative of the kinetic lability characteristic of octahedral nickel(II) complexes.