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All mesoporous ordered silicas , and especially the thick walled SBA - type materials and the PMO contain a surprisingly high amount of total silanol sites , albeit that up to 90 % of these silanols are buried inside the walls and are not reachable for small silanes .
 Chemical: silicas; Chemical: PMO; Chemical: silanol; Chemical: silanols
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: silicas; Chemical: PMO; Chemical: silanol; Chemical: silanols