Question

The $\widehat{CNC}$ bond angle in $CH_3NCS$ is:

• A. < $109^\circ28'$
• B. <$120^\circ$
• C.

  $120^\circ$

• D. $112^\circ$

Answer 1

Answer: (C)

(C)

Answer 2

The nitrogen atom in $CH_3NCS$ exhibits resonance. While the most common Lewis structure suggests $sp^2$ hybridization with a lone pair leading to an angle less than $120^\circ$, a significant resonance contributor involves a triple bond to nitrogen, implying $sp$ hybridization and a linear angle of $180^\circ$. Experimental data shows the actual $\widehat{CNC}$ bond angle to be approximately $141.6^\circ$, which is greater than $120^\circ$, indicating a dominant influence of the $sp$ hybridized linear character.