GeI2
Germanium(II) iodide · Germanium diiodide
GeI2 is a stable, semiconducting germanium halide widely used as a precursor in chemical synthesis and materials science.
About Germanium(II) iodide
Germanium(II) iodide is a stable inorganic compound composed of germanium and iodine. As a semiconducting material, it serves as a critical precursor in the synthesis of more complex germanium-based structures and thin films. Its position on the convex hull confirms its thermodynamic stability, making it a reliable building block for chemical vapor transport and other solid-state reactions. The compound is highly regarded in research for its structural versatility, supported by a significant body of reported experimental and theoretical data. It remains a foundational material for exploring the chemistry of group 14 halides in various electronic and optoelectronic applications.
Key Properties
Cross-validated computational properties for Germanium(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 GeI2. 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 GeI2, 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. |
|---|---|---|---|---|---|
| — | — | 2.16 | 0.0000 | -0.455 | — |
| R-3m (No. 166) | trigonal | 2.07 | 0.0000 | -0.382 | — |
| P-3m1 (No. 164) | trigonal | 2.02 | 0.0000 | -3.152 | 4.74 |
| — | — | 2.20 | 0.0001 | -0.455 | — |
| R-3m (No. 166) | trigonal | 1.98 | 0.0002 | -0.382 | — |
| — | — | 2.09 | 0.0005 | -0.455 | — |
| R-3m (No. 166) | trigonal | 2.01 | 0.0008 | -3.151 | 4.79 |
| R-3m (No. 166) | trigonal | 2.06 | 0.0221 | -0.360 | — |
| P-6m2 (No. 187) | hexagonal | 1.96 | 0.1196 | -3.032 | 4.22 |
| — | — | 1.91 | 0.1216 | -0.334 | — |
| — | — | 1.21 | 0.1491 | -0.306 | — |
| P-6m2 (No. 187) | hexagonal | 1.76 | 0.1612 | -0.221 | — |
Applications
Where Germanium(II) iodide is used.
Frequently Asked Questions
Common questions about Germanium(II) iodide, answered from cross-validated data.
What is GeI2?
GeI2 is a stable, semiconducting germanium halide widely used as a precursor in chemical synthesis and materials science.
What is GeI2 used for?
What is the band gap of GeI2?
Is GeI2 a metal, semiconductor, or insulator?
Is GeI2 thermodynamically stable?
How many polymorphs of GeI2 are known?
What elements does GeI2 contain?
Where does the data for GeI2 come from?
How It Compares
As a primary representative of the germanium halide family, this compound serves as a benchmark for stability and reactivity within its class, providing a consistent platform for studying low-valent germanium chemistry.
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)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
Analyze GeI2 in the Lattice Graph platform
Polymorph comparison, confidence scoring, supply-chain risk, and patent monitoring — across 85 source databases.
Explore the Platform →