Knowledge Bank

The microwave spectrum of the normal species of vinyldifluorophosphine $(PF2C2H3)$ has been examined. One conformer is observed. The ground state constants are: $A=7158.9(2)$ MHz: $B=3041.32(2)$ MHz; $C=2486.60(2)$ MHz. The dipole components are $\mu a=2.42(1)D$ and $\mu c=0.08(5)D$. The molecular conformation which best fits the observed effective moments of inertia has a plane of symmetry with the fluorines trans to the vinyl group. Estimates of the approximate structural parameters of $PF2C2H3$ are made in several ways. The estimated p-c distance is $1.79\pm 0.02$ {\AA}.