7222
Upon replacement of counterions of monovalent potassium with those of divalent calcium , sarin diffusion slows but remains substantial in all ionomers considered , especially at high sarin concentrations .
 Chemical: potassium; Chemical: calcium; Chemical: sarin; Chemical: sarin
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: potassium; Chemical: calcium; Chemical: sarin; Chemical: sarin