56959
" Hopkalite " is the trade name for a number of mixtures that mainly consist of oxides of Copper and Manganese , which are used as catalysts for the conversion of Carbon monoxide to Carbon dioxide when exposed to the oxygen in the air at room temperature .
 Copper, Manganese
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Copper, Manganese