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This tutorial review summarizes the organometallic chemistry derived from the half - sandwich complex [ ( eta ( 7 ) - C ( 7 ) H ( 7 ) ) ZrCl ( tmeda ) ] , which was used as an efficient and versatile starting material for the incorporation of monoanionic ligands into the cycloheptatrienyl zirconium coordination sphere by conventional salt metathesis reactions .
 Chemical: ( eta ( 7 ) - C ( 7 ) H ( 7 ) ) ZrCl ( tmeda ); Chemical: cycloheptatrienyl zirconium
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: ( eta ( 7 ) - C ( 7 ) H ( 7 ) ) ZrCl ( tmeda ); Chemical: cycloheptatrienyl zirconium