The name/synonym for ligand NO2 (curated from ChEBI, PubChem, and PDB databases):

1NITRITE
2NO2(-)
3[NO2](-)
4NITRITE ANION
5DIOXONITRATE(1-)
6DIOXIDONITRATE(1-)
7NITRIT
8DIOXONITRATE(III)
9NITROUS ACID, ION(1-)
10NITRITE(1-)
11NITRITE ION