16443
Compound 1 yields size - tunable hollow nanospheres ( HNSs ) with a narrow size distribution , and 2 yields various morphologies ranging from microtubules to microrods via self - assembly induced by hydrogen bonding and pi - pi stacking interactions .
 Chemical: hydrogen
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: hydrogen