Question

consider the molecule tetracyanoethylene: :n≡c :n≡c c=c c≡n: c≡n: part 1 of 2 how many sigma bonds are there in the tetracyanoethylene molecule? part 2 of 2 how many pi bonds are there in the tetracyanoethylene molecule?

Explanation:

Step1: Analyze single - bonds

Single - bonds are all sigma bonds. In the tetracyanoethylene molecule, count the single C - C and C - N single bonds. There are 4 C - C single bonds and 4 C - N single bonds.

Step2: Analyze double - and triple - bonds

A double - bond consists of 1 sigma and 1 pi bond, and a triple - bond consists of 1 sigma and 2 pi bonds. The central C = C double - bond contributes 1 sigma bond, and each of the 4 C≡N triple - bonds contributes 1 sigma bond.
The total number of sigma bonds is \(4 + 4+1 + 4=9\).

Step3: Analyze pi - bonds

The central C = C double - bond contributes 1 pi bond, and each of the 4 C≡N triple - bonds contributes 2 pi bonds.
The total number of pi bonds is \(1+4\times2 = 9\).

Answer:

Part 1 of 2: 9
Part 2 of 2: 9