Hybridisation of singlet carbene is:
sp2
1. Types of carbenes: They are of two types: (I) singlet and (II) triplet.
Generally, carbenes are known for having two odd e−s, i.e., both the e−s are present in different orbitals or two electrons present in the same orbital (called lone pair of e−s or nonbonding e−s).
In singlet carbenes, both the electrons are present in the same orbital with opposite spin (antiparallel), the electrons are paired in non-bonding sp2 hybrid orbital. They are produced by the photolysis of CH2N2 (diozomethane). Triplet carbenes have two unpaired electrons, one in each of an sp and a p orbital.
2. Hybridisation: They use sp2 hybridised orbitals in bond formation, with bent shape. Singlet methylene show a bond angle (H-C-H) of 103∘, and bond length of 112 pm (C-H).