Question

Which molecule among $A{X}_3,A{X}_4,A{X}_5$ and $A{X}_6$ is most likely to have a trigonal bipyramidal structure if $A$ has no lone pair?

• A. $A{X}_3$
• B. $A{X}_5$
• C. $A{X}_6$
• D. Both $A$ and $B$
  

Answer 1

Answer: (B)

$A{X}_5$

Trigonal bipyramidal geometry corresponds to $s{p}^{3}d$ hybridization with $5$ bond pars and no lone pairs

$\Rightarrow$ For which there must be $5$ monovalent atoms.

$\therefore A{X}_5$ is most likely to have a trigonal bipyramidal structure if A has no lone pair.