YbF2

YbF2 is an insulating ytterbium fluoride compound that exhibits a wide electronic band gap and notable structural complexity.

FYb
Crystal structure of YbF2 (tetragonal, P42/mnm (No. 136))
Ground-state structure · Materials Project
Overview

About YbF2

YbF2 is an insulating fluoride compound that features a wide electronic band gap. It is characterized by its significant structural diversity, with numerous reported configurations across various materials databases, reflecting complex coordination environments for the ytterbium cation.

While it is an interesting subject for fundamental research into rare-earth halides, it is identified as being above the thermodynamic hull. This suggests that the compound may be metastable or unstable under standard conditions, requiring specific synthesis pathways to stabilize its structure.

At a glance

Key Properties

Cross-validated computational properties for YbF2, aggregated across 3 databases.

Band Gap

2.57–8.54 eV
Range across DFT structures · ground state: insulator

Energy Above Hull

0.000 eV/atom
Best (lowest) across sources

Stability

Stable
3 DFT sources

Structures

36
3 databases, 9 space groups
Validation

Cross-Source DFT Agreement

How well independent DFT databases agree on the thermodynamics of YbF2. Tight agreement means computed properties can be trusted without re-running calculations.

Agreement Score

0.00 / 1.00
Trust tier: low

Hull Spread

0.521 eV
EAH spread across sources

Sources Compared

3
jarvis, materials_project, oqmd

Space Group Consensus

All match
Crystallography

Reported Structures

Lowest-energy structures reported for YbF2, ranked by energy above hull.

Space GroupCrystal SystemBand Gap (eV)E above hull (eV/atom)E/atom (eV)Density (g/cm³)
——7.790.0000-4.539—
P42/mnm (No. 136)tetragonal6.990.0000-4.386—
——7.830.0006-4.539—
——8.540.0467-4.493—
——7.310.0952-4.444—
——7.490.1050-4.434—
——7.190.1119-4.427—
——7.590.1143-4.425—
——7.430.1693-4.370—
——7.180.3246-4.215—
——5.170.3864-4.153—
P42/mnm (No. 136)tetragonal6.730.5210-17.7617.62
Uses

Applications

Where YbF2 is used.

Fundamental materials researchSolid-state chemistry studiesRare-earth halide investigations
Reference

Frequently Asked Questions

Common questions about YbF2, answered from cross-validated data.

What is YbF2?

YbF2 is an insulating ytterbium fluoride compound that exhibits a wide electronic band gap and notable structural complexity.

More questions
What is YbF2 used for?
YbF2 is used in fundamental materials research, solid-state chemistry studies, and rare-earth halide investigations.
What is the band gap of YbF2?
YbF2 has a DFT-computed band gap of 2.57–8.54 eV across 36 reported structures. Standard DFT underestimates band gaps, so the measured gap is typically larger.
Is YbF2 a metal, semiconductor, or insulator?
DFT predicts a wide band gap of up to 8.54 eV (an insulator or wide-band-gap material).
Is YbF2 thermodynamically stable?
Yes — YbF2 sits on the convex hull (energy above hull 0 eV/atom), i.e. stable.
What is the crystal structure of YbF2?
The reference structure of YbF2 is tetragonal symmetry, space group P42/mnm (No. 136).
How many polymorphs of YbF2 are known?
36 structures of YbF2 are reported across 3 databases, spanning 9 distinct space groups.
What elements does YbF2 contain?
YbF2 contains F and Yb (2 elements).
Where does the data for YbF2 come from?
YbF2 data is cross-referenced from oqmd, jarvis, materials_project, mpaloe.
Comparison

How It Compares

As a rare-earth fluoride, YbF2 occupies a unique niche in inorganic chemistry where its stability and structural properties are heavily influenced by the electronic configuration of the ytterbium ion. Unlike more robust and thermodynamically stable fluoride counterparts, this compound serves as a critical case study for understanding the limits of structural persistence in insulating halide systems.

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.

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