20488
The aggregation behavior of cationic 5 , 5 ' , 6 , 6 ' - tetrachloro - 1 , 1 ' , 3 , 3 ' - tetraethylbenzimidacarbocyanine with chloride ( TTBC - Cl ) or iodide counterions ( TTBC - I ) in aqueous solution is investigated by absorption , linear dichroism , and fluorescence spectroscopies , as well as cryogenic transmission electron microscopy ( cryo - TEM ) and atomic force microscopy ( AFM ) .
 Chemical: 5 , 5 ' , 6 , 6 ' - tetrachloro - 1 , 1 ' , 3 , 3 ' - tetraethylbenzimidacarbocyanine; Chemical: chloride; Chemical: TTBC - Cl; Chemical: iodide; Chemical: TTBC - I
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: 5 , 5 ' , 6 , 6 ' - tetrachloro - 1 , 1 ' , 3 , 3 ' - tetraethylbenzimidacarbocyanine; Chemical: chloride; Chemical: TTBC - Cl; Chemical: iodide; Chemical: TTBC - I