22751
Intermediate chain length ( 16 <= i <= 50 ) n - alkanes are known to surface freeze at temperatures that are up to three degrees higher than the equilibrium melting point [ B . M . Ocko et al . , Phys . Rev . E , 1997 , 55 , 3164 - 3182 ] .
 Chemical: n - alkanes
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: n - alkanes