To understand the role of structure on the position of the octahedral Equation or symbol description not availableFe3+/Fe2+ redox couple in compounds having the same polyanions, four iron phosphates: Equation or symbol description not availableLi3Fe2(PO4)3,LiFeP2O7,Fe4(P2O7)3, and Equation or symbol description not availableLiFePO4 were investigated. They vary in structure as well as in the manner in which the octahedral iron atoms are linked to each other. The Equation or symbol description not availableFe3+/Fe2+ redox couple in the above compounds lies at 2.8, 2.9, 3.1, and 3.5 eV, respectively, below the Fermi level of lithium. The reason for the difference in the position of the redox couples is related to changes in the P‒O bond lengths as well as to changes in the crystalline electric field at the iron sites.