22802
2 , 2 , 6 , 6 - Tetramethylpiperidine - 1 - oxyl ( TEMPO ) is a low molecular weight nitroxide and stable free radical .
 Chemical: 2 , 2 , 6 , 6 - Tetramethylpiperidine - 1 - oxyl; Chemical: TEMPO
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: 2 , 2 , 6 , 6 - Tetramethylpiperidine - 1 - oxyl, TEMPO 
Answer:
 Chemical: 2 , 2 , 6 , 6 - Tetramethylpiperidine - 1 - oxyl; Chemical: TEMPO