Abstract The mixed-valence triiodide salts of 1′,1″-dihalobiferrocenes having two different kinds of halogen substituents were synthesized. Their 57Fe-Mössbauer spectra showed an averaged-valence state; i.e., one doublet even at 4.2 K, as found in the triiodide salts of 1′,1′″-dibromo- and 1′,1′″-diiodobiferrocenes.