24200
In addition , the compounds are effective when the metal ions are substituted by iron but lack potentiation activity when the metal ions are substituted by sodium , signifying the importance of the metal ion .
 Chemical: iron; Chemical: sodium
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: iron; Chemical: sodium