HgF2
mercury(II) fluoride · mercuric fluoride
Mercury(II) fluoride is a stable, semiconducting inorganic compound primarily utilized as a selective fluorinating agent in chemical synthesis.

About mercury(II) fluoride
Mercury(II) fluoride is a binary inorganic compound that exists as a thermodynamically stable phase on the convex hull. Its semiconducting electronic character distinguishes it within the broader landscape of mercury-based halides, reflecting a unique balance of ionic and covalent bonding interactions.
This material is highly valued in chemical synthesis for its ability to act as a selective fluorinating agent. Due to its well-documented structural behavior and stability, it serves as a reliable reagent in laboratory settings where precise control over halogen exchange processes is required.
Key Properties
Cross-validated computational properties for mercury(II) fluoride, 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.
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.
Reported Structures
Lowest-energy structures reported for HgF2, 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. |
|---|---|---|---|---|---|
| Fm-3m (No. 225) | cubic | 0.97 | 0.0000 | -20.112 | 9.24 |
| Pnma (No. 62) | orthorhombic | 0.76 | 0.0137 | -20.099 | 10.11 |
| P42/mnm (No. 136) | tetragonal | 0.40 | 0.0592 | -20.053 | 7.89 |
| P1 (No. 1) | Triclinic | — | — | — | 9.84 |
| C2/c (No. 15) | Monoclinic | — | — | — | 4.74 |
| C2/c (No. 15) | Monoclinic | — | — | — | 5.72 |
| C2/c (No. 15) | Monoclinic | — | — | — | 7.00 |
| P1 (No. 1) | Triclinic | — | — | — | 7.64 |
| P-1 (No. 2) | Triclinic | — | — | — | 8.48 |
| P-1 (No. 2) | Triclinic | — | — | — | 8.39 |
| C2 (No. 5) | Monoclinic | — | — | — | 8.79 |
| P1 (No. 1) | Triclinic | — | — | — | 4.49 |
Applications
Where mercury(II) fluoride is used.
Frequently Asked Questions
Common questions about mercury(II) fluoride, answered from cross-validated data.
What is HgF2?
Mercury(II) fluoride is a stable, semiconducting inorganic compound primarily utilized as a selective fluorinating agent in chemical synthesis.
What is HgF2 used for?
What is the band gap of HgF2?
Is HgF2 a metal, semiconductor, or insulator?
Is HgF2 thermodynamically stable?
What is the crystal structure of HgF2?
What is the density of HgF2?
How many polymorphs of HgF2 are known?
What elements does HgF2 contain?
Where does the data for HgF2 come from?
How It Compares
As a member of the mercury halide family, mercury(II) fluoride occupies a distinct niche due to its high thermodynamic stability and specific reactivity profile. Unlike its lighter or heavier halogen counterparts, this fluoride exhibits a unique structural versatility, supported by a vast body of experimental and computational data that confirms its reliability for specialized chemical applications.
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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