why there are no structures of methene & methyne?
The compounds methene and methyne do not exist in nature. This is because:
The alkene family have the general formula CnH2n where n is a natural number(which starts from 1). If we substitute 1 in place of n, then we get the formula CH2. CH2 has no independent existence, as the tetravalent nature of carbon is being violated. The first member of this series is ethene.
The alkyne family have the general formula CnH2n-2 where n is a natural number(which starts from 1). If we substitute 1 in place of n, then we get the formula CH0 which cannot exist. So, the first member of this series is ethyne.
Hence, the structures of methene and methyne is not possible to find out.