18910
Bond valence sum analysis , based on the precise structural parameters ( bond lengths and coordination number ) extracted from the in situ PDF data , suggests that anion partitioning occurs during the electrochemical reaction , with the rutile phase being F - rich and the rock salt phase being O - rich .
 Chemical: F; Chemical: O
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