19556
The TRIR spectra of this adduct display an unusually low CO stretching frequency for the antisymmetric CO stretching mode , suggesting that one carbonyl ligand adopts a bent configuration to avoid a 19 - electron count at the metal center .
 Chemical: CO; Chemical: CO; Chemical: carbonyl
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: CO; Chemical: CO; Chemical: carbonyl