pyramidal molecule

pyramidal molecule

[¦pir·ə‚mid·əl ′mäl·ə‚kyül]
(chemistry)
A molecular structure in the shape of a pyramid in which the central atom at the peak possesses either three or four valence bonds that are directed to the other atoms, which form the base of the pyramid.
References in periodicals archive ?
ESDIAD shows, for example, that the phosphorus atom in the pyramidal molecule phosphorus trifluorine (PF3) does all the clinging when the molecule is adsorbed onto the surface of a single crystal of nickel; emitted fluorine ions indicate that the molecule looks like an upside-down three-legged stool with fluorine atoms flung into the air directly above nickel atoms.