11552
Combined with ex - situ cryo X - ray photoelectron spectroscopy surface analysis , the surface speciation of enargite surface oxidation has been obtained , comparing the newly fractured natural enargite surface with those that have been electrochemically oxidized at pHs 4 and 10 .
 Chemical: enargite; Chemical: enargite
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: enargite; Chemical: enargite