| Noun | 1. | atomic number 6 - an abundant nonmetallic tetravalent element occurring in three allotropic forms: amorphous carbon and graphite and diamond; occurs in all organic compoundsfullerene - a form of carbon having a large molecule consisting of an empty cage of sixty or more carbon atoms chemical element, element - any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter char - a charred substance charcoal, wood coal - a carbonaceous material obtained by heating wood or other organic matter in the absence of air carbon black, lampblack, smut, soot - a black colloidal substance consisting wholly or principally of amorphous carbon and used to make pigments and ink activated carbon, activated charcoal - powdered or granular carbon used for purifying by adsorption; given orally (as a slurry) it is an antidote for some kinds of poisons coal - fossil fuel consisting of carbonized vegetable matter deposited in the Carboniferous period adamant, diamond - very hard native crystalline carbon valued as a gem limestone - a sedimentary rock consisting mainly of calcium that was deposited by the remains of marine animals | |