The infrared matrix isolation spectra and normal coordinate analysis of LiBeF3 and the related species Li2BeF4 and (LiBeF3)2

Beryllium fluoride vapor was reacted with ⁶Lif: and ⁷LiF at 900–1000 °C in an effusion tube. The infrared spectrum of the effusate was obtained in a neon matrix, in the range 4000-190 cm^?1. One mixed halide, LiBeF₃ was identified and the existence of (LiBeF₃)₂ or Li₂BeF₄ inferred. For LiBeF₃ seven of the possible nine infrared frequencies were observed. A normal coordinate analysis for LiBeF₃ is presented and used to assign the experimental frequencies. Calculated mean amplitudes of vibration and calculated frequencies from normal coordinate analyses of Li₂BeF₄ and (LiBeF₃)₂ are reported.