2 2 6 6-tetramethylpiperidine-1-oxylradical July 8, 2019 16 32 64 128 2 2 6 6-tetramethylpiperidine-1-oxyl radical 2 2 6 6-tetramethylpiperidine-1-oxyl (free radical) 2 2 6 6-tetramethyl-piperidine-n-oxyl 2 2 6 6-tetramethylpiperidine-1-oxyl 2 2 6 6-tetramethyl-piperidine