16200
Linking molecule - NP interactions with a series of changes of packing density and surface lattice spacings of NPs allows for an interpretation of principles governing the nucleation , structure stability , and transformation of PbS NP - assembled supercrystals .
 Chemical: PbS
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: PbS