Brief summaries are given of work on the vibrational spectra of the following compounds. (1)N(SiH<sub>3</sub>)<sub>3</sub>. A Raman study of the <sup>14</sup>N-<sup>15</sup>N isotopic shift of the totally symmetric NSi<sub>3</sub> stretching mode confirms that the heavy atom skeleton is planar in the gas phase. In condensed phases it is slightly distorted from D<sub>3h</sub> in some undetermined manner. (2) Si(NCO)<sub>4,</sub> Ge(NCO)<sub>4</sub>, and Ge(N<sub>3</sub>)<sub>4</sub>. Each of these molecules has some Raman bands with depolarization ratios between 0 and 0.75, showing that the molecules are not tetrahedral. (3) Cyclopropenone-d<sub>0</sub> and -d<sub>2</sub>. A good assignment of the fundamentals has been made, and the forms of the normal modes calculated. The hands at 1483 cm<sup>−1</sup> (d<sub>0</sub>) and 1409 cm<sup>−1</sup> (d<sub>2</sub>) are nearly pure C=C stretches, making them the lowest such modes known. (4, 5) Tetramethylenecyclobutane and its perchloro derivative. The former is planar (D<sub>4h</sub>); the latter is not (D<sub>2d</sub>). (6) F<sub>2</sub>C=C=C=CF<sub>2</sub>. This is planar (D<sub>2d</sub>). (7) B<sub>4</sub>Cl<sub>4</sub>. This has an unusual B<sub>4</sub> tetrahedral cage. A reliable set of assignments has been made and force constants determined. (8) Trithiadiborolanes. The B<sub>2</sub>S<sub>3</sub> ring is planar.
Foil A. Miller, "Molecules We Have Recently Met," Appl. Spectrosc. 29, 461-469 (1975)
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