7522
Mechanism of homogeneous reduction of CO2 by pyridine : proton relay in aqueous solvent and aromatic stabilization .
 Chemical: CO2; Chemical: pyridine
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: CO2, pyridine 
Answer:
 Chemical: CO2; Chemical: pyridine