K

Potassium · Kalium

Potassium is a highly reactive, soft alkali metal that is thermodynamically stable and widely studied for its metallic properties.

K
Crystal structure of K (cubic, Im-3m (No. 229))
Ground-state structure · Materials Project
Overview

About Potassium

Potassium is a fundamental metallic element known for its high reactivity and presence on the convex hull, indicating exceptional thermodynamic stability. As a soft, silvery-white metal, it serves as a cornerstone in inorganic chemistry and materials science research.

Its metallic nature allows for excellent electrical conductivity, making it a subject of extensive study across numerous structural databases. Due to its unique electronic configuration, it remains a vital component in understanding fundamental atomic interactions and metallic bonding behavior.

At a glance

Key Properties

Cross-validated computational properties for Potassium, aggregated across 6 databases.

Band Gap

0.12 eV
Range across DFT structures · ground state: insulator

Energy Above Hull

0.000 eV/atom
Best (lowest) across sources

Stability

Stable
4 DFT sources

Structures

146
6 databases, 21 space groups
Validation

Cross-Source DFT Agreement

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

Agreement Score

1.00 / 1.00
Trust tier: high

Hull Spread

0.000 eV
EAH spread across sources

Sources Compared

3
jarvis, materials_project, oqmd

Space Group Consensus

Mixed (most: Im-3m (No. 229))
Crystallography

Reported Structures

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

Space GroupCrystal SystemBand Gap (eV)E above hull (eV/atom)E/atom (eV)Density (g/cm³)
——0.000.00000.000—
Im-3m (No. 229)cubic0.000.00000.000—
Cmce (No. 64)orthorhombic0.000.0000-6.0180.85
Cmce (No. 64)orthorhombic0.000.00000.001—
Im-3m (No. 229)cubic0.000.00000.000—
P21/m (No. 11)monoclinic0.000.00000.001—
I41/amd (No. 141)tetragonal0.000.00000.061—
P4132 (No. 213)cubic0.000.0000-0.009—
P63/mmc (No. 194)hexagonal0.000.00000.000—
Fm-3m (No. 225)cubic0.000.00000.000—
Fm-3m (No. 225)cubic0.000.00000.000—
Pnma (No. 62)orthorhombic0.000.00000.034—
Uses

Applications

Where Potassium is used.

Chemical synthesisFertilizer productionHeat transfer fluidsLaboratory reagents
Reference

Frequently Asked Questions

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

What is K?

Potassium is a highly reactive, soft alkali metal that is thermodynamically stable and widely studied for its metallic properties.

More questions
What is K used for?
Potassium (K) is used in chemical synthesis, fertilizer production, heat transfer fluids, and laboratory reagents.
What is the band gap of K?
Potassium (K) has a DFT-computed band gap of 0.12 eV across 146 reported structures. Standard DFT underestimates band gaps, so the measured gap is typically larger.
Is K a metal, semiconductor, or insulator?
DFT predicts a band gap of up to 0.12 eV (a semiconductor). Measured gaps are typically larger.
Is K thermodynamically stable?
Yes — Potassium (K) sits on the convex hull (energy above hull 0 eV/atom), i.e. stable.
What is the crystal structure of K?
The reference structure of Potassium (K) is cubic symmetry, space group Im-3m (No. 229).
How many polymorphs of K are known?
146 structures of K are reported across 6 databases, spanning 21 distinct space groups.
What elements does K contain?
Potassium (K) contains K (1 element).
Where does the data for K come from?
K data is cross-referenced from oqmd, jarvis, materials_project.
Comparison

How It Compares

As a primary alkali metal, potassium defines the standard for reactivity and metallic character within its group. It serves as a benchmark for understanding the structural and electronic trends observed in lighter and heavier group members.

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)

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