27857
From simulation a high homogeneous electron transfer rate ( 6 x 10 ( 9 ) M ( - 1 ) s ( - 1 ) ) is found for the one - electron reduction of oxygen to superoxide .
 Chemical: oxygen; Chemical: superoxide
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: oxygen; Chemical: superoxide