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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
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: iron oxides; Chemical: iron; Chemical: bis ( 2 , 4 - methylpentadienyl ) iron