# What is the molecular shape of PF_3?

$\text{Trigonal pyramidal}$
There are 4 regions of electron density around the central phosphorus atom, one of which is a lone pair. Given simple VSEPR, a structure based on a tetrahedron is specified. But because we describe structure in relation to atoms, and not electron pairs, the structure of $P {F}_{3}$ should be pyramidal, an analogue of ammonia.
This site reports that /_F-P-F=107""^@, so it seems that we are not too offbase. The /_F-N-F=102.5""^@ in $N {F}_{3}$ is included for comparison.