HfI4
HfI4 has a DFT band gap of 2.35–3.30 eV across 21 reported structures in 7 space groups; its lowest-energy polymorph is monoclinic (C2/c (No. 15)). Cross-validated across 3 computational databases.
HfI
Overview
Key Properties
Cross-validated computational properties for HfI4, aggregated across 3 databases.
Band GapEnergy needed to move an electron from the valence band to the conduction band. Lower or zero values tend to behave more metallic; larger gaps are more insulating or semiconducting.
2.35–3.30 eV
Range across DFT structures
Energy Above HullThermodynamic distance from the most stable set of competing phases. 0 eV/atom is on the convex hull; small positive values may still be experimentally accessible.
0.000 eV/atom
Best (lowest) across sources
StabilityA plain-language summary of the best reported energy-above-hull result. It reflects whether the lowest-energy structure is on, near, or far from the stability hull.
On hull (stable)
2 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
21
3 databases, 7 space groups
Crystallography
Reported Structures
Lowest-energy structures reported for HfI4, ranked by energy above hull.
| Space GroupSymmetry classification of the crystal arrangement. The number is the international space-group index. | Crystal SystemBroad lattice family, such as cubic, tetragonal, monoclinic, or triclinic, derived from unit-cell symmetry. | Band Gap (eV)Electronic gap calculated for this specific reported structure, measured in electronvolts. | E above hull (eV/atom)Thermodynamic distance from the convex hull for this structure, normalized per atom. Lower is generally more stable. | E/atom (eV)Computed total energy normalized per atom. Use energy above hull, not this value alone, when comparing stability. | Density (g/cm³)Mass per relaxed crystal volume, reported in grams per cubic centimeter. |
|---|---|---|---|---|---|
| C2/c (No. 15) | monoclinic | 2.35 | 0.0000 | -4.427 | 5.24 |
| Pa-3 (No. 205) | cubic | 3.30 | 0.0300 | -4.397 | 4.56 |
| Cm (No. 8) | Monoclinic | — | — | — | 7.38 |
| C2/c (No. 15) | — | — | — | — | — |
| Cm (No. 8) | Monoclinic | — | — | — | 6.04 |
| Cm (No. 8) | Monoclinic | — | — | — | 9.75 |
| Pmm2 (No. 25) | Orthorhombic | — | — | — | 6.04 |
| I4/m (No. 87) | Tetragonal | — | — | — | 7.30 |
| Pmm2 (No. 25) | Orthorhombic | — | — | — | 5.97 |
| P1 (No. 1) | Triclinic | — | — | — | 5.53 |
| P-1 (No. 2) | Triclinic | — | — | — | 4.33 |
| P-1 (No. 2) | Triclinic | — | — | — | 12.68 |
Reference
Frequently Asked Questions
Common questions about HfI4, answered from cross-validated data.
What is the band gap of HfI4?
HfI4 has a DFT-computed band gap of 2.35–3.30 eV across 21 reported structures.
More questions
Is HfI4 a metal, semiconductor, or insulator?
With a wide band gap up to 3.30 eV it is an insulator / wide-band-gap material.
Is HfI4 thermodynamically stable?
Yes — HfI4 sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of HfI4?
The lowest-energy reported polymorph of HfI4 is monoclinic symmetry, space group C2/c (No. 15).
What is the density of HfI4?
The computed density of the ground-state structure of HfI4 is 5.24 g/cm³.
How many polymorphs of HfI4 are known?
21 structures of HfI4 are reported across 3 databases, spanning 7 distinct space groups.
What elements does HfI4 contain?
HfI4 contains Hf and I (2 elements).
Where does the data for HfI4 come from?
HfI4 data is cross-referenced from materials_project, mpaloe, jarvis.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
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