Chemical Reactions in Molecular Sieves. I. NO3 Free Radical from Direct Reaction of NO2 and Atomic Oxygen

Abstract
NO2 adsorbed in the cavities of 13‐X molecular sieve reacts with oxygen atoms from a microwave discharge to form the NO3 free radical which remains trapped within the cavities. The EPR spectrum of the NO3 at 300°K is a single symmetrical line with g=2.019 and 11 G width between points of maximum slope. At 85°K a 5.9‐G isotropic hyperfine coupling constant with the single 14N nucleus is resolved. The trapped NO3 free radical is apparently freely rotating even at 85°K. The odd‐electron NO2 molecule is observed to exhibit free rotation in the 13‐X sieve only down to ∼150°K.