5273
The formation of chromium oxide nanoparticles by gamma radiolysis of Cr ( VI ) ( CrO ( 4 ) ( 2 - ) or Cr ( 2 ) O ( 7 ) ( 2 - ) ) solutions was investigated as a function of pH and initial Cr ( VI ) concentration by measuring [ Cr ( VI ) ] , the particle concentration ( [ Cr ( III ) ( col ) ] ) and [ H ( 2 ) ] , and by characterizing the particles using TEM , Raman , FTIR and XPS .
 chromium oxide, Cr ( VI ), CrO ( 4 ) ( 2 - ), Cr ( 2 ) O ( 7 ) ( 2 - ), Cr ( VI ), Cr ( VI ), Cr ( III ), H ( 2 )
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 chromium oxide, Cr ( VI ), CrO ( 4 ) ( 2 - ), Cr ( 2 ) O ( 7 ) ( 2 - ), Cr ( VI ), Cr ( VI ), Cr ( III ), H ( 2 )