27650
Compared with TOCNs with sodium , lithium , potassium , and cesium carboxylate groups , TOCN with free carboxyl groups ( TOCN - COOH ) had much high and selective H2 gas permeation performance .
 Chemical: sodium; Chemical: lithium; Chemical: potassium; Chemical: cesium; Chemical: carboxylate; Chemical: carboxyl; Chemical: COOH; Chemical: H2
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: sodium; Chemical: lithium; Chemical: potassium; Chemical: cesium; Chemical: carboxylate; Chemical: carboxyl; Chemical: COOH; Chemical: H2