what is the correct order for the stability of carbene?

a)singlet>triplet

b)triplet>singlet

c)singlet=triplet

d)none of these

explain with reason

yup rite

Triplet carbenes have two unpaired e- , one in  sp2 & one in p orbital......there is only one non bonding e- ......so less repulsion...n more stable

Singlet Carbenes have 2  non bonding e-, one in non bonding sp2 orbital  & the other in empty p orbital..so more repulsion n hence less stable

yes your ans is correct

don't you think ans should be singlet>triplet because in singlet odd electron are paired in hybrid orbital

.while in triplet both odd electron remain unpaired which result in dec its stability

all of you have a misconcept developed,

actually  a carbene is a highly reactive organic molecule containing a carbon atom with six valence electrons and having the general formula: R¹R²C: (two substituents and two electrons)

what all of you are saying is true for methylene (:CH₂) or any other type of carbene where the substituent does not contain any empty p or d orbital.

But taking the case of dichlorocarbene(:CCl₂) we find that singlet carbene is much more stable than triplet because in singlet carbene delocalisation of electron is possible in the empty d orbital of Cl thereby making it far more stable than triplet  carbene. Same is the case when one or two phenyl ring are substituents.

So in general unless you mention the two substituent nothing can be said about the stablity of the two carbenes.