The structure of [ZnEn3]CrO4 (En is ethylendiamine) complex salt is determined. It is demonstrated that at room temperature the crystallographic characteristics are as follows: а = 9.0942(4) Å, с = 9.7673(4) Å, space group Р-31с (No. 163). Contrary to [ZnEn3]SO4, disordered chromate anions participate in its formation. When [ZnEn3]CrO4 is heated in a hydrogen atmosphere up to 700 °C, zinc chromite spinel is formed (а = 8.328 Å, space group Fd-3m), which has a complex nanocrystalline structure.