Vibrational properties of the mixed-valence iron oxo-complex

The room temperature Raman and infrared studies of the tribridged oxo-iron complex (NH4)2[{FeIII3(μ3-O)(HCOO)6}2{FeII(H2O)2(HCOO)6}] (oxoFeFe) were performed and the proposed assignment of the observed vibrational modes has been presented. The studied mixed-valence compound crystallizes in P-1 space group and is constructed from triangular units Fe3IIIO and divalent iron ions linked by formate anions. We prove that using the hydrothermal synthesis with a mixture of acetonitrile and propylamine as a solvent can be an alternative method to obtain the oxoFeFe material. The phase purity of the studied crystal is confirmed by its powder XRD pattern.