16194
Correlating superlattice polymorphs to internanoparticle distance , packing density , and surface lattice in assemblies of PbS nanoparticles .
 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