4549
Reversible and cyclical transformations between solid and hollow nanostructures in confined reactions of manganese oxide and silica within nanosized spheres .
 Chemical: manganese oxide; Chemical: silica
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: manganese oxide; Chemical: silica