Tetrahedrane is a simple 'proposed' hydrocarbon in the family of 'platonic hydrocarbons'
It has a very simple chemical formula C4H4 , and calculations show that it should be relatively stable. Methods for making the compound are as yet unknown (although derivative molecules, e.g tetra-tert-butyl-tetrahedrane, have been made). Its chemical properties therefore remain theoretical.
Technical information at Wikipedia