Matrix reactions of Na, K, Rb, and Cs atoms with N2O: Infrared spectra and geometries of K2O, Rb2O, and Cs2O

Abstract

Reactions of the heavy alkali metal atoms with N2O have been studied using the matrix reaction technique. No sodium oxides were produced; however, the metals K, Rb, and Cs yielded products with infrared absorptions appropriate for assignment to ν3 of the M–O–M high-temperature molecules. The identification of these molecules is based on oxygen isotopic shifts and on experiments codepositing two different alkali metals. Apex angle calculations indicate that K2O and Rb2O have valence angles in the 160°–180° range and that the Cs2O angle is approximately 130°–140°. This trend is rationalized on the basis of increasing metal-metal bonding with the more polarizable alkali cation. The KO and CsO fundamentals were observed at 384 and 314 cm−1 in solid nitrogen.