Chiefly British; graphite

ETYM Greek graphein to write: cf. French graphite. Related to Graphic.
Used as a lubricant and as a moderator in nuclear reactors; SYN. black lead, plumbago.
Blackish gray, laminar, crystalline form of carbon. It is used as a lubricant and as the active component of pencil lead.
The carbon atoms are strongly bonded together in sheets, but the bonds between the sheets are weak so that the sheets are free to slide over one another. Graphite has a very high melting point (3,500şC/6,332şF), and is a good conductor of heat and electricity. It absorbs neutrons and is therefore used to moderate the chain reaction in nuclear reactors. + prikaži više