Some Chemical Symbols - (n.)

O2: molecular oxygen

O3: ozone

N2: molecular nitrogen

N2O: nitrous oxide

NO: nitric oxide

NO3: nitrate radical

NOx: Sum of NO and NO2

NO3- : nitrate ion

HNO3: nitric acid

NH3: ammonia

NH4+ : ammonium ion

H2: molecular hydrogen

H2O: water

OH: hydroxyl

HO2: hydroperoxyl

HOx: the sum OH and HO2

C: carbon; there are 3 isotopes: 12C, 13C, 14C

CO: carbon monoxide

CO2: carbon dioxide

F2: molecular fluorine

Cl2: molecular chlorine

Br2: molecular bromine

CFC: chlorofluorocarbon

CFC-11: CFCl3 or trichlorofluoromethane

CFC-12: CF2Cl2 or dichlorodifluoromethane

CFC-113: C2F3Cl2 or trichlorotrifluoroethane

CFC-114: C2F4Cl2 or dichlorotetrafluoroethane

CFC-115: C2F5Cl or chloropentafluoroethane