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Furthermore , we calculate adiabatic electron affinities in aqueous solvent for CO ( 2 ) , Py , and Py . CO ( 2 ) of 47 . 4 , 37 . 9 , and 66 . 3 kcal / mol respectively , indicating that the anionic complex PyCOO ( - ) stabilizes the anionic radicals CO ( 2 ) ( - ) and Py ( - ) to facilitate low barrier ET .
 CO ( 2 ), Py . CO ( 2 ), PyCOO ( - ), CO ( 2 ) ( - ), Py ( - )
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 CO ( 2 ), Py . CO ( 2 ), PyCOO ( - ), CO ( 2 ) ( - ), Py ( - )