HgI2
Mercury(II) iodide · Mercuric iodide
Mercury(II) iodide is a stable semiconducting material primarily used for its sensitive radiation detection capabilities.
About Mercury(II) iodide
Mercury(II) iodide is a thermodynamically stable compound that functions as a semiconductor. Its ability to effectively interact with high-energy radiation makes it a subject of significant interest in materials science research. The material is characterized by a high degree of structural complexity, with numerous reported phases across scientific databases. This structural diversity underscores its importance in fundamental solid-state studies and specialized technological applications. Its utility is primarily driven by its electronic character, which allows it to operate effectively in room-temperature detection environments. By providing a stable platform for charge carrier transport, it remains a key material for developing advanced sensing devices.
Key Properties
Cross-validated computational properties for Mercury(II) iodide, aggregated across 5 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.
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.
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.
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of HgI2. Tight agreement means computed properties can be trusted without re-running calculations.
Agreement ScoreA normalized confidence score summarizing how closely independent DFT databases agree. Higher scores mean tighter cross-source agreement.
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
Reported Structures
Lowest-energy structures reported for HgI2, 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. |
|---|---|---|---|---|---|
| — | — | 1.34 | 0.0000 | -0.400 | — |
| P42/nmc (No. 137) | tetragonal | 1.33 | 0.0000 | -1.684 | 5.89 |
| P42/nmc (No. 137) | tetragonal | 0.97 | 0.0000 | -0.155 | — |
| I41/acd (No. 142) | tetragonal | 1.46 | 0.0000 | -1.684 | 5.78 |
| — | — | 1.34 | 0.0002 | -0.399 | — |
| I41/amd (No. 141) | tetragonal | 1.35 | 0.0006 | -1.683 | 5.86 |
| P42/nmc (No. 137) | tetragonal | 1.38 | 0.0007 | -1.683 | 5.88 |
| Cmc21 (No. 36) | orthorhombic | 2.33 | 0.0009 | -1.683 | 5.83 |
| I41/amd (No. 141) | tetragonal | 1.04 | 0.0009 | -0.154 | — |
| — | — | 1.26 | 0.0011 | -0.399 | — |
| P42/nmc (No. 137) | tetragonal | 1.11 | 0.0015 | -0.153 | — |
| Cmc21 (No. 36) | orthorhombic | 1.77 | 0.0030 | -0.152 | — |
Applications
Where Mercury(II) iodide is used.
Patent Landscape
1 patent reference HgI2 or close compositional variants.
| Patent | Title | Assignee | Granted |
|---|---|---|---|
| 4091084 | Purification of HgI.sub.2 for nuclear detector fabrication | — | — |
Frequently Asked Questions
Common questions about Mercury(II) iodide, answered from cross-validated data.
What is HgI2?
Mercury(II) iodide is a stable semiconducting material primarily used for its sensitive radiation detection capabilities.
What is HgI2 used for?
What is the band gap of HgI2?
Is HgI2 a metal, semiconductor, or insulator?
Is HgI2 thermodynamically stable?
What is the crystal structure of HgI2?
What is the density of HgI2?
How many polymorphs of HgI2 are known?
What elements does HgI2 contain?
Where does the data for HgI2 come from?
How It Compares
As a distinct inorganic compound, mercury(II) iodide serves as a foundational material for high-performance radiation detection, standing out for its ability to function without the need for cryogenic cooling, which is often required for other semiconductor-based detectors.
Data sources & attribution
- oqmd — Data from the OQMD (oqmd.org). Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comp. Mater. 1, 15010 (2015). (CC-BY-4.0)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
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