18818
Control over the oxidation state and crystalline phase of thin - film iron oxides was achieved by low - temperature atomic layer deposition ( ALD ) , utilizing a novel iron precursor , bis ( 2 , 4 - methylpentadienyl ) iron .
 Chemical: iron oxides; Chemical: iron; Chemical: bis ( 2 , 4 - methylpentadienyl ) iron
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: iron oxides, iron, bis ( 2 , 4 - methylpentadienyl ) iron 
Answer:
 Chemical: iron oxides; Chemical: iron; Chemical: bis ( 2 , 4 - methylpentadienyl ) iron