29824
For the first time , we were able to precisely control the edge lengths of Ag octahedra below 100 nm , and the lower limit of size could even be pushed down to 20 nm .
 Chemical: Ag
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: Ag