mu-oxidobis(oxidonitrogen) 75.991 76.01168 CAS:122413-35-8 CHEBI:29800 InChI=1S/N2O3/c3-1-5-2-4 N2O3 O=N-O-N=O O=NON=O ONONO SEOYNUHKXVGWFU-UHFFFAOYSA-N chebi_ontology dinitrosooxidane mu-oxidobis(oxidonitrogen) nitrogen oxide