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
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: PbS 
Answer:
 Chemical: PbS