14673
While the cation exchange procedure , performed in solution phase approach , was restricted so far to chalcogenide based semiconductor nanocrystals , here ferrite - based nanocrystals were subjected to a Fe ( 2 + ) to Co ( 2 + ) cation exchange procedure .
 Chemical: ferrite; Chemical: Fe ( 2 + ); Chemical: Co ( 2 + )
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: ferrite; Chemical: Fe ( 2 + ); Chemical: Co ( 2 + )