Question

Which of the following molecule(s) have a bent shape?

• A. $Cl{F}_2^{+}$
• B. $Cl{F}_2^{-}$
• C. $B{F}_2^{-}$
• D. None of these

Answer 1

Answer: (A), (C)

$B{F}_2^{-}$

Start with the shape of $Cl{F}_3$ - an approximately T-shaped molecule.
Should we remove an $F^{+}$ from that, then we get a linear molecule,
just like the triodide anion. Removing an $F^{-}$ from $Cl{F}_3$ gives
$Cl{F}_2^{+}$ which is bent like $H_{2}O$ and $HOCl$.


From $Cl{F}_3$, should we remove an $F^{+}$, we get:

$B{F}_3$ is a trigonal planar molecule. If we remove $F^{+}$ from the
Lewis acid, we get $B{F}_2^{-}$ which is a bent molecule.