GeI2

Germanium(II) iodide · Germanium diiodide

GeI2 is a stable, semiconducting germanium halide widely used as a precursor in chemical synthesis and materials science.

GeI
Crystal structure of GeI2 (trigonal, P-3m1 (No. 164))
Ground-state structure · Materials Project
Overview

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.

At a glance

Key Properties

Cross-validated computational properties for Germanium(II) iodide, aggregated across 3 databases.

Band Gap

1.96–2.02 eV
Range across DFT structures

Energy Above Hull

0.000 eV/atom
Best (lowest) across sources

Stability

On hull (stable)
2 DFT sources

Structures

55
3 databases, 14 space groups
Crystallography

Reported Structures

Lowest-energy structures reported for GeI2, ranked by energy above hull.

Space GroupCrystal SystemBand Gap (eV)E above hull (eV/atom)E/atom (eV)Density (g/cm³)
P-3m1 (No. 164)trigonal2.020.0000-3.1524.74
R-3m (No. 166)trigonal2.010.0008-3.1514.79
P-6m2 (No. 187)hexagonal1.960.1196-3.0324.22
P1 (No. 1)Triclinic3.98
C2/c (No. 15)Monoclinic4.33
P1 (No. 1)Triclinic7.20
P1 (No. 1)Triclinic4.07
P1 (No. 1)Triclinic5.01
P-3m1 (No. 164)Trigonal4.11
P-3m1 (No. 164)Trigonal4.24
P-3m1 (No. 164)Trigonal4.19
P-1 (No. 2)Triclinic7.44
Uses

Applications

Where Germanium(II) iodide is used.

Chemical vapor transportPrecursor for germanium-based thin filmsSolid-state synthesis
Reference

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.

More questions
What is GeI2 used for?
Germanium(II) iodide (GeI2) is used in chemical vapor transport, precursor for germanium-based thin films, and solid-state synthesis.
What is the band gap of GeI2?
Germanium(II) iodide (GeI2) has a DFT-computed band gap of 1.96–2.02 eV across 55 reported structures.
Is GeI2 a metal, semiconductor, or insulator?
With a band gap up to 2.02 eV it is a semiconductor.
Is GeI2 thermodynamically stable?
Yes — Germanium(II) iodide (GeI2) sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of GeI2?
The lowest-energy reported polymorph of Germanium(II) iodide (GeI2) is trigonal symmetry, space group P-3m1 (No. 164).
What is the density of GeI2?
The computed density of the ground-state structure of Germanium(II) iodide (GeI2) is 4.74 g/cm³.
How many polymorphs of GeI2 are known?
55 structures of GeI2 are reported across 3 databases, spanning 14 distinct space groups.
What elements does GeI2 contain?
Germanium(II) iodide (GeI2) contains Ge and I (2 elements).
Where does the data for GeI2 come from?
GeI2 data is cross-referenced from materials_project, mpaloe.
Comparison

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
  • materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
  • mpaloe — Data from mpaloe.

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