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The structure is dependent on the metal center ; for the early transition metals eta ( 3 ) coordination is favored , whereas eta ( 2 ) is more favorable for the later transition metals .
 Chemical: transition metals; Chemical: transition metals
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: transition metals; Chemical: transition metals