Formation of molecular chromium(IV) oxide (CrO2) by photolysis of Cr(CO)6 in O2-doped argon matrices

Abstract

The binary chromium oxide, CrO₂, is produced upon prolonged broad-band u.v.–visible irradiation of Cr(CO)₆ isolated in O₂-doped argon matrices at ca. 12 K. Infrared spectroscopic studies involving isotopic substitution with ¹⁸O show that CrO₂ is a non-linear dioxo molecule with an upper limit for the O–Cr–O bond angle of 117 ± 3°. Measurements of the intensities of the infrared absorptions arising from the symmetric and antisymmetric CrO₂ stretches of this molecule give a value for O–Cr–O of 112 ± 2°, confirming the non-linear structure.