Question

what is trigonal bipyramidal geometry??????

Answer 1

An example of trigonal bipyramid molecular geometry that results from five electron pair geometry is PCl5. The phosphorus has 5 valence electrons and thus needs 3 more electrons to complete its octet. However this is an example where five chlorine atoms present and the octet is expanded.

The Lewis diagram is as follows:
Cl = 7 e- x 5 = 35 e-
P = 5 e- = 5 e-

Total = 40 e-

The Chlorine atoms are as far apart as possible at nearly 90o and 120obond angle. This is trigonal bipyramid geometry.

Trigonal bipyramid geometry is characterized by 5 electron pairs.

Answer 2

In chemistry a trigonal bipyramid formation is a molecular geometry with one atom at the center and 5 more atoms at the corners of a triangular bipyramid. This is one geometry for which the bond angles surrounding the central atom are not identical (see also pentagonal bipyramid), because there is no geometrical arrangement with five terminal atoms in equivalent positions. Examples of this molecular geometry are phosphorus pentafluoride (PF5), and phosphorus pentachloride (PCl5) in the gas phase.[1]

Trigonal bipyramidal molecular geometryExamplesPF5, Fe(CO)5Point groupD3hCoordination number5Bond angle(s)90°, 120°μ (Polarity)0