Chiral compounds that do not have a tetrahedral atom with four different groups

7 Chiral compounds that do not have a tetrahedral atom with four different groups 

A molecule is chiral if it is not superimposable on its mirror image. A tetrahedral atom with four different groups is just one of the factors that confer chirality on a molecule. There are a number of molecules where a tetrahedral atom with four different groups is not present, yet they are not superimposable, i.e. chiral. For example, 1,3-dichloroallene is a chiral molecule, hut it does not have a tetrahedral atom with four different groups. 

An allene is a hydrocarbon in which one atom of carbon is connected by double bonds with two other atoms of carhon. Allene is also the common 

Robinson, M. J. T. Organic Stereochemistry, Oxford University Press, Oxford, 2002. 

---