The vibrational spectra and structure of trisilylarsine and trisilylstibine

The infra-red spectra of As(SiH3)3 and Sb(SiH3)3 in the vapour and the solid states have been observed in the range 250–4000 cm−1; the corresponding spectrum of liquid Sb(SiH3)3 is also reported, and the Raman spectra of liquid As(SiH3)3 and Sb(SiH3)3 at −60° have been obtained. The combined results provide evidence that the AsSi3 skeleton is planar, but do not make it possible to distinguish between the planar and pyramidal models for the SbSi3 skeleton.