What is "tetrahedrane"

n. (context organic compound English) hypothetically, one of the Platonic hydrocarbons, C₄H₄, having the carbon atoms at the vertices of a tetrahedron; has not yet been synthesized, and would be very unstable.

Tetrahedrane is a platonic hydrocarbon with chemical formula and a tetrahedral structure. Extreme angle strain (carbon bond angles deviate considerably from the tetrahedral bond angle of 109.5°) prevents this molecule from forming naturally.