Synonyms: TEMPO; TEMPO, free radical,(2,2,6,6-Tetramethyl-1-piperidinyloxy,free; 2,2,6,6-Tetramethyl-1-piperidinyloxy, free radical; 2,2,6,6-Tetramethyl-1-piperinedinyloxy; TEMPO, free radical; 2,2,6,6-Tetramethylpiperidinooxy; 2,2,6,6-tetramethylpiperidinyl-1-oxide