18911
The F - and O - rich phases react sequentially ; Fe in a F - rich environment reacts preferentially during both discharge and charge .
 Chemical: F; Chemical: O; Chemical: Fe; Chemical: F
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: F; Chemical: O; Chemical: Fe; Chemical: F