A series of bulkily substituted ferrocenium triiodides with general formula (RC~5H~4)~2FeI~3 have been synthesized and characterized by elementary analysis, IR spectrum, mass spectrum, ESR spectrum, Mossbauer spectrum and conductivity. The crystal structure of [CH~2 (CH~2)~3C(2-CH~2C~5H~4N)C~5H~4]~2FeI~4.H~2O has been determined. The crystal belongs to triclinic, space group P-1, the cell parameters are a=0.9593(1), b=1.3999(2), c=1.4537(2)nm。α=109.64(1), β=97.25(1) , γ =104.69(1)ⅲ。V=1.7299nm^3, Mr=1030.13, Dx=1.98g/cm^3, Z=2. The results indicate that the substituted ferrocene is partially oxidized by iodine, therefore the central metal iron shows mixed valence state. Because of the effect of bulky substituents in cyclopentadienyl ring the polyiodide chains of the I~3^- ions are not formed, the conductivities of these compounds are very low.

Key words: FERROCENE, IODIDE, CRYSTAL STRUCTURE, ELEMENTAL ANALYSIS, INFRARED SPECTROPHOTOMETRY, MASS SPECTROGRAPHY, PARAMAGNETIC RESONANCE, MOSSBAUER SPECTROMETRY