The honeycomb and hyperhoneycomb polymorphs of IrI3

Danrui Ni, Kasey P. Devlin, Guangming Cheng, Xin Gui, Weiwei Xie, Nan Yao, Robert J. Cava

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4 Scopus citations


The synthesis of IrI3 at high pressure in its layered honeycomb polymorph is reported. Its crystal structure is refined by single crystal X-ray diffraction. Faults in the honeycomb layer stacking are observed by single crystal diffraction, synchrotron powder diffraction, and transmission electron microscopy. A previously unreported “hyperhoneycomb” polymorph of IrI3 (β-IrI3), is also reported - Its structure in space group Fddd is determined by single crystal XRD. Both materials are highly-resistive diamagnetic semiconductors, consistent with a low spin d6 configuration for Ir(III). The two- and three-dimensional Ir arrays in these polymorphs of IrI3 are analogous to those found in the α- and β-polymorphs of Li2IrO3, although the Ir electron configurations are different. IrI3 may be of future interest in the fabrication of new quantum materials.

Original languageEnglish (US)
Article number123240
JournalJournal of Solid State Chemistry
StatePublished - Aug 2022

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry


  • High pressure synthesis
  • Honeycomb structure
  • Hyperhoneycomb structure
  • Iridium triiodide
  • Synchrotron diffraction
  • Transmission electron microscopy


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