HgI2

Mercury(II) iodide · Mercuric iodide

Mercury(II) iodide is a stable semiconducting material primarily used for its sensitive radiation detection capabilities.

HgI
Crystal structure of HgI2 (tetragonal, P42/nmc (No. 137))
Ground-state structure · Materials Project
Overview

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.

At a glance

Key Properties

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

Band Gap

1.33–2.33 eV
Range across DFT structures

Energy Above Hull

0.000 eV/atom
Best (lowest) across sources

Stability

On hull (stable)
2 DFT sources

Structures

33
3 databases, 9 space groups
Crystallography

Reported Structures

Lowest-energy structures reported for HgI2, ranked by energy above hull.

Space GroupCrystal SystemBand Gap (eV)E above hull (eV/atom)E/atom (eV)Density (g/cm³)
P42/nmc (No. 137)tetragonal1.330.0000-1.6845.89
I41/acd (No. 142)tetragonal1.550.0000-1.6845.78
I41/amd (No. 141)tetragonal1.350.0006-1.6835.86
P42/nmc (No. 137)tetragonal1.380.0007-1.6835.88
Cmc21 (No. 36)orthorhombic2.330.0009-1.6835.83
P-1 (No. 2)Triclinic6.75
P1 (No. 1)Triclinic9.15
P42/nmc (No. 137)Tetragonal5.53
P42/nmc (No. 137)Tetragonal5.32
P42/nmc (No. 137)
P42/nmc (No. 137)
C2/c (No. 15)Monoclinic5.94
Uses

Applications

Where Mercury(II) iodide is used.

Radiation detectionX-ray imagingGamma-ray spectroscopyPhotoconductive devices
Reference

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.

More questions
What is HgI2 used for?
Mercury(II) iodide (HgI2) is used in radiation detection, x-ray imaging, gamma-ray spectroscopy, and photoconductive devices.
What is the band gap of HgI2?
Mercury(II) iodide (HgI2) has a DFT-computed band gap of 1.33–2.33 eV across 33 reported structures.
Is HgI2 a metal, semiconductor, or insulator?
With a band gap up to 2.33 eV it is a semiconductor.
Is HgI2 thermodynamically stable?
Yes — Mercury(II) iodide (HgI2) sits on the convex hull (energy above hull 0 eV/atom), i.e. on hull (stable).
What is the crystal structure of HgI2?
The lowest-energy reported polymorph of Mercury(II) iodide (HgI2) is tetragonal symmetry, space group P42/nmc (No. 137).
What is the density of HgI2?
The computed density of the ground-state structure of Mercury(II) iodide (HgI2) is 5.89 g/cm³.
How many polymorphs of HgI2 are known?
33 structures of HgI2 are reported across 3 databases, spanning 9 distinct space groups.
What elements does HgI2 contain?
Mercury(II) iodide (HgI2) contains Hg and I (2 elements).
Where does the data for HgI2 come from?
HgI2 data is cross-referenced from materials_project, mpaloe, jarvis.
Comparison

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
  • 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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