16927
The wobbling motion of azide ion within the frame of metal azide ion pairs was weakly dependent on the countercation .
 Chemical: azide; Chemical: metal azide
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: azide, metal azide 
Answer:
 Chemical: azide; Chemical: metal azide