4-Hydroxy-2,2,6,6-te, 4-Hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl,TEMPOL, HYDROXY-TEMPO; NR-I, 4-HYDROXY-2,2,6,6-TETRAMETHYL PIPERIDINOXYL, Amino compound: 4-Hydroxy-2,2,6,6-tetramethylpiperidinoxyl, 4-Hydroxy-2,2,6,6-tetramethylpiperidinoxyl, TEMPOL (4-HYDROXY-TEMPO)