22958
Reactions of nickel oxide cluster ions , NinOn + x ( + ) ( n = 4 - 10 , x = - 1 ~ + 3 ) , with CO in a He buffer gas were investigated using mass spectrometry .
 Chemical: nickel oxide; Chemical: NinOn + x ( + ); Chemical: CO; Chemical: He
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: nickel oxide; Chemical: NinOn + x ( + ); Chemical: CO; Chemical: He