The Raman spectrum of CuCr2O4 (Fig. 15e) presents main bands at ~680 (A1g), 590 (F2g), 530 (F2g) and 440 (Eg) cm−1. The A1g mode Cathepsin G due to the symmetric stretching of the oxygen atoms along with the Cr–O tetrahedral bonds, the Eg mode and the F2g mode at 590 cm−1 are due to the symmetric and asymmetric bending of oxygen with respect to Cr, respectively, and the F2g mode at 530 cm−1 is due to the asymmetric stretching of the Cr–O bond.
The absence of the D and G bands of the C–C stretching vibrations characteristic to carbon  in the endothermic Raman measurements indicate the complete combustion of the precursor organic compounds.
Chromium substituted copper ferrite powders, CuFe2−xCrxO4 (0≤x≤2), were prepared by the precursor method through the thermal decomposition of multimetallic gluconate compounds.
A series of (NH4)2[CuFe2−xCrx(C6H10O7)4(OH)2]·nH2O gluconate precursors was obtained using different systems Cu2+:(Fe3+2−x,Crx3+):8C6O7H11−, where 0≤x≤2 and C6O7H11−=gluconate anion.