19782
Anomalously low reactivity is observed in the photochlorination of AB - stacked bilayer graphene in comparison with that of few - layer graphene .
 Chemical: graphene; Chemical: graphene
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: graphene