Question

A molecule with the formula$\mathrm{A}{\mathrm{B}}_3$, in which A and B represent different atoms, could have one of three different shapes. Sketch and name the three different shapes that this molecule might have. Give an example of a molecule or ion that has each shape.

Short answer

A molecule with molecular formula $\mathrm{A}{\mathrm{B}}_3$ can have T-shape for example $\mathrm{I}\mathrm{C}{\mathrm{l}}_3$, trigonal planar for example $\mathrm{B}{\mathrm{F}}_3$and trigonal pyramidal for example $\mathrm{N}{\mathrm{H}}_3$ shapes shown as follows:

Step-by-step solution

Definition of Concept

There are two types of bonds in trigonal bipyramidal structures: axial bonds and equatorial bonds. So, there are five bonds in the trigonal bipyramidal geometry.

Sketch and name the three different shapes that this molecule

A molecule with the molecular formula$\mathrm{A}{\mathrm{B}}_3$is made up of one A atom and two B atoms. There are three atoms that are bonded together. As a result, this molecule can have three molecular shapes: when there are only three bond pairs and no lone pair on the central A-atom, it has trigonal planar electron pair geometry and trigonal pyramidal shape; when there are three bond pairs and one lone pair on the central A-atom, it has tetrahedral electron pair geometry and trigonal pyramidal shape; and when there are three bond pairs and two lone pairs on the central A.

Therefore, the required shapes are below: