5NQI:
reference: Synthesis, Thermodynamic Properties, and Crystal Structure of RNA Oligonucleotides Containing 5-Hydroxymethylcytosine., Riml C, Lusser A, Ennifar E, Micura R, J Org Chem. 2017 Aug 4;82(15):7939-7945. doi: 10.1021/acs.joc.7b01171. Epub 2017 , Jul 14. PMID: 28707898

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