15543
Absence of edge States in covalently bonded zigzag edges of graphene on ir ( 111 ) .
 Chemical: graphene; Chemical: ir ( 111 )
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: graphene; Chemical: ir ( 111 )