Infrared and ultraviolet–visible spectroscopic studies on manganese heptoxide (Mn2O7)

Infrared and u.v.–visible spectra are reported for Mn2O7 both in the solid phase and as a monomeric species isolated in low-temperature matrices. The i.r, spectra are consistent with the expected bridged structure, and indicate a relatively wide O3Mn–O–MnO3 angle. Characteristic i.r. absorptions are found at ca. 955 cm–1νasym(MnO), ca. 890 cm–1νsym(MnO), and ca. 775 cm–1νasym(Mn–O). The electronic spectrum of Mn2O7 shows a number of charge-transfer bands with partially resolved vibrational progressions, and their features are compared with those of related manganese(VII) oxo-species.