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A metal - organic framework ( MOF ) bearing the aqua - hydroxo species ( O2H3 ) ( - ) in the framework , as well as the processes that govern the equilibrium aqua - hydroxo ( O2H3 ) ( - ) <--> hydroxyl ( OH ) in Sc - MOFs , are studied experimentally and theoretically .
 Chemical: aqua - hydroxo; Chemical: ( O2H3 ) ( - ); Chemical: aqua - hydroxo; Chemical: ( O2H3 ) ( - ); Chemical: hydroxyl; Chemical: OH; Chemical: Sc
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: aqua - hydroxo; Chemical: ( O2H3 ) ( - ); Chemical: aqua - hydroxo; Chemical: ( O2H3 ) ( - ); Chemical: hydroxyl; Chemical: OH; Chemical: Sc