28721
The structural information of the first shell around a Co ion was expressed in terms of the hydration number , Co - O distance and Debye - Waller factor .
 Chemical: Co; Chemical: Co - O
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: Co; Chemical: Co - O