NAHCOLITE

colourless to white carbonate mineral (NaHCO3), a naturally occurring sodium bicarbonate. Its structure consists of planar chains of carbonate groups linked with hydrogen bonds; planes are linked together by sodium in six-fold coordination with oxygen. Nahcolite commonly forms by reaction of carbon dioxide with the mineral trona (q.v.) in evaporated lake basins. It is found in large quantities in the central salt body of Searles Lake, Calif., and as concentrations up to five feet (1.5 metres) in diameter in the oil-shale deposits of Green River Formation, Colo., where it is commercially mined. For detailed physical properties, see carbonate mineral (table).