27143
Study of the microcharacter of ultrastable aqueous foam stabilized by a kind of flexible connecting bipolar - headed surfactant with existence of magnesium ion .
 Chemical: magnesium
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: magnesium