Nitrogen trifluoride is found to be stable towards photo-oxidation reactions that limit the atmospheric lifetimes of many gaseous species. Reactions with species such as OH and HO2 are thermodynamically unfavorable. The reaction with O3, while thermodynamically favorable, is found to be too slow to be of atmospheric importance. Measurements of the NF3 absorption cross-sections from 180 to 250 nm yield values that are smaller than those previously reported, and indicate an atmospheric lifetime against photodissociation in the stratosphere of about seven hundred years. In addition, the infrared band strengths were determined in order to enable estimates of greenhouse warming potentials. A slow reaction with aqueous Fe2+ was observed at room temperature; it could provide an additional destruction mechanism in the environment. ¿ American Geophysical Union 1995