Problem 9.16

Describe the characteristic electron-domain geometry of each of the following numbers of electron domains around a central atom:

Consult Table 9.1 while working this problem - it is very important that you know these shapes and why certain numbers of electron domains take on certain geometries!

(a) 3

Three electron domains will assume a planar arrangement with 120^o angles between them to minimize repulsion. This is the trigonal planar shape.

(b) 4

Four electron domains will orient themselves at 109.5^o angles. This shape is tetrahedral.

(c) 5

Five electron domains will orient themselves with three pairs at 120^o angles in the plane around the central atom (the equatorial positions) and two pairs 180^o apart (the axial positions.) This is the trigonal bipyramidal shape.

(d) 6

Six electron pairs will orient themselves at 90^o to one another - this is the octahedral electron-domain geometry.