11983
They form various types of oxides , such as simple oxides ( containing the O ion ) , peroxides ( containing the ion , where there is a single bond between the two oxygen atoms ) , superoxides ( containing the ion ) , and many others .
 O
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 O