KNO2

Potassium nitrite · Nitrous acid potassium salt

Potassium nitrite is a stable, semiconducting inorganic salt widely used as a chemical reagent and preservative.

KNO
Crystal structure of KNO2 (monoclinic, Cm (No. 8))
Ground-state structure · Materials Project
Overview

About Potassium nitrite

Potassium nitrite is a stable inorganic compound that exists as a semiconducting material. Its position on the thermodynamic convex hull highlights its robust nature, making it a reliable chemical intermediate in various synthetic pathways.

Due to its chemical properties, this compound is frequently utilized in specialized industrial processes. Its electronic character and structural stability across multiple reported configurations underscore its importance as a consistent reagent in chemical manufacturing.

At a glance

Key Properties

Cross-validated computational properties for Potassium nitrite, aggregated across 5 databases.

Band Gap

2.27–2.55 eV
Range across DFT structures · ground state: wide gap

Energy Above Hull

0.000 eV/atom
Best (lowest) across sources

Stability

Stable
3 DFT sources

Structures

24
5 databases, 4 space groups
Validation

Cross-Source DFT Agreement

How well independent DFT databases agree on the thermodynamics of KNO2. 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

All match
Crystallography

Reported Structures

Lowest-energy structures reported for KNO2, ranked by energy above hull.

Space GroupCrystal SystemBand Gap (eV)E above hull (eV/atom)E/atom (eV)Density (g/cm³)
P21/c (No. 14)monoclinic2.550.0000-6.1292.01
——2.420.0000-1.183—
P21/c (No. 14)monoclinic2.320.0000-1.023—
Cm (No. 8)monoclinic2.500.0004-6.1281.96
Imm2 (No. 44)orthorhombic2.500.0006-6.1281.92
Cm (No. 8)monoclinic2.480.0166-6.1121.95
Cm (No. 8)monoclinic2.520.0172-1.006—
Cm (No. 8)monoclinic2.520.0175-1.005—
Imm2 (No. 44)orthorhombic2.450.0186-1.004—
——2.270.0240-1.159—
——0.000.0315-1.152—
——2.520.0423-1.141—
Uses

Applications

Where Potassium nitrite is used.

Food preservationChemical synthesisCorrosion inhibitionLaboratory reagent
Reference

Frequently Asked Questions

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

What is KNO2?

Potassium nitrite is a stable, semiconducting inorganic salt widely used as a chemical reagent and preservative.

More questions
What is KNO2 used for?
Potassium nitrite (KNO2) is used in food preservation, chemical synthesis, corrosion inhibition, and laboratory reagent.
What is the band gap of KNO2?
Potassium nitrite (KNO2) has a DFT-computed band gap of 2.27–2.55 eV across 24 reported structures. Standard DFT underestimates band gaps, so the measured gap is typically larger.
Is KNO2 a metal, semiconductor, or insulator?
DFT predicts a band gap of up to 2.55 eV (a semiconductor). Measured gaps are typically larger.
Is KNO2 thermodynamically stable?
Yes — Potassium nitrite (KNO2) sits on the convex hull (energy above hull 0 eV/atom), i.e. stable.
What is the crystal structure of KNO2?
The reference structure of Potassium nitrite (KNO2) is monoclinic symmetry, space group Cm (No. 8).
What is the density of KNO2?
The computed density of the ground-state structure of Potassium nitrite (KNO2) is 1.96 g/cm³.
How many polymorphs of KNO2 are known?
24 structures of KNO2 are reported across 5 databases, spanning 4 distinct space groups.
What elements does KNO2 contain?
Potassium nitrite (KNO2) contains K, N, and O (3 elements).
Where does the data for KNO2 come from?
KNO2 data is cross-referenced from materials_project, oqmd, jarvis, mpaloe, cod.
Comparison

How It Compares

As a primary inorganic nitrite, this compound serves as a fundamental reference point for understanding the stability and reactivity of alkali metal nitrogen-oxygen salts.

Data sources & attribution
  • materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
  • 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)
  • mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
  • cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)

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