4807
Wet planetary milling of MgO into CaCO ( 3 ) allowed efficient particle size reduction and the effective dispersion of MgO throughout the particles .
 MgO, CaCO ( 3 ), MgO
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 MgO, CaCO ( 3 ), MgO