24575
Comparison of X - ray reflectivity data for strongly hydrated alkali - metal ions ( Li ( + ) and Na ( + ) ) , for which ion pairing to TPFB ( - ) ions across the interface is not expected , to data for weakly hydrated alkali - metal ions ( Rb ( + ) and Cs ( + ) ) indicates that the Gibbs energy of adsorption due to ion pairing at the interface must be small ( < 1 kBT per ion pair ) for both the CsCl and RbCl samples .
 Chemical: alkali - metal; Chemical: Li ( + ); Chemical: Na ( + ); Chemical: TPFB ( - ); Chemical: alkali - metal; Chemical: Rb ( + ); Chemical: Cs ( + ); Chemical: CsCl; Chemical: RbCl
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: alkali - metal; Chemical: Li ( + ); Chemical: Na ( + ); Chemical: TPFB ( - ); Chemical: alkali - metal; Chemical: Rb ( + ); Chemical: Cs ( + ); Chemical: CsCl; Chemical: RbCl