18002
The role of halogen bonds in self - assembled networks for systems with Br and I ligands has recently been studied with scanning tunneling microscopy ( STM ) , which provides physical insight at the atomic scale .
 Chemical: halogen; Chemical: Br; Chemical: I
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: halogen; Chemical: Br; Chemical: I