18006
Our study shows that , in contrast to Br - and I - related halogen bonds , Cl - related halogen bonds weakly contribute to the molecular structure due to a modest positive potential ( sigma hole ) of the Cl ligands .
 Chemical: Br; Chemical: I; Chemical: halogen; Chemical: Cl; Chemical: halogen; Chemical: Cl
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: Br; Chemical: I; Chemical: halogen; Chemical: Cl; Chemical: halogen; Chemical: Cl