(MEH-THEE-LAEN ) A TETRA-VALENT, HYDRO-CARBON GROUP, THAT IS MADE OF A CARBON ATOM, WITH TWO HYDRON ATOMS, CH2, BOTH BONDED TO THE CARBON ATOM,WITH CO-VALENT BONDS,. AND TWO OTHER BONDS, TO TWO OTHER ATOMS. THEY ARE FOUND IN ALKANES, IN ALKANE-LIKE CARBON BRANCH EXTENSIONS, ALKENES, ALKYNES AND BETWEEN ARENE RINGS IN PHENYL ANTHRENES.