2XIL:
reference: The nature of the ferryl heme in compounds I and II., Gumiero A, Metcalfe CL, Pearson AR, Raven EL, Moody PC, J Biol Chem. 2010 Nov 8. PMID: 21062738

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).