▁of ▁other ▁functional ▁groups ▁for ▁the ▁hydro gen . ▁ ▁The ▁carbon ▁atom ▁is ▁left ▁with ▁either ▁one ▁or ▁three ▁un pa ired ▁electrons ▁( uns atisf ied ▁val ence ▁b onds ), ▁depending ▁on ▁the ▁mole c ule ' s ▁exc itation ▁state ; ▁making ▁it ▁a ▁radical . ▁According ly , ▁the ▁chemical ▁formula ▁can ▁be ▁CH • ▁or ▁CH 3 • ▁ ▁( also ▁written ▁as ▁ <0xE2> <0xAB> <0xB6> CH ); ▁each ▁dot ▁representing ▁an ▁un pa ired ▁electron . ▁ ▁The ▁corresponding ▁system atic ▁names ▁are ▁m eth y ly l id ene ▁or ▁hyd rid oc ar bon ( • ), ▁and ▁m eth an et ri yl ▁or ▁hyd rid oc ar bon ( 3 • ). ▁ ▁However , ▁the ▁formula ▁is ▁often ▁written ▁simply ▁as ▁CH . ▁ ▁M eth yl id y ne ▁is ▁a ▁highly ▁re active ▁gas , ▁that ▁is ▁quickly ▁destroyed ▁in ▁ordinary ▁conditions ▁but ▁is ▁abund ant ▁in ▁the ▁inter stell ar ▁medium ▁( and ▁was ▁one ▁of ▁the ▁first ▁mole cules ▁to ▁be ▁detected ▁there ). ▁ ▁N omen cl ature ▁ ▁The ▁trivial ▁name ▁car by ne ▁is ▁the ▁preferred ▁I UP AC ▁name . ▁▁ ▁Following ▁the ▁subst it utive ▁nom en cl ature , ▁the ▁mole c ule ▁is ▁viewed ▁as ▁m eth ane ▁with ▁three ▁hydro gen ▁atoms ▁removed , ▁yield ing ▁the ▁system atic ▁name ▁" m eth yl id y ne ". ▁ ▁Following ▁the ▁add itive ▁nom en cl ature ,