Infrared Spectrum and Structure of Matrix Isolated Thallous Oxide

Abstract

The infrared absorption spectrum of Tl2O isolated in solid Ar, Kr, and N2 matrices was observed. From the observed spectra and the isotope shifts for Tl216O and Tl218O it is possible to conclude that Tl2O has a bent symmetrical structure and that the Tl–O–Tl angle is near 90°. The Tl–O bond distance is estimated to be 1.86 Å. The Tl–Tl bond distance is estimated to be 2.63 Å, and it is proposed that there is a strong Tl–Tl bond within the molecule. A force constant analysis and a comparison of the calculated and observed entropy of Tl2O support the proposed structure. The three fundamental frequencies for Tl216O in an argon matrix are ν1 = 571 cm−1, [ν2 ≃ 130 cm−1], and ν3 = 643 cm−1.