KCN

Potassium cyanide · Cyanide of potassium

Potassium cyanide is a highly reactive inorganic salt that functions as a potent chemical reagent in industrial and laboratory settings.

CKN
Crystal structure of KCN (monoclinic, Cc (No. 9))
Ground-state structure · Materials Project
Overview

About Potassium cyanide

Potassium cyanide is a crystalline inorganic compound characterized by its insulating electronic nature. It is widely recognized for its high reactivity and role in various specialized chemical synthesis pathways. Due to its position above the thermodynamic hull, the compound is considered inherently unstable under standard conditions. Its structural versatility is evidenced by the numerous distinct crystalline arrangements reported across scientific databases.

At a glance

Key Properties

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

Band Gap

0.06–5.31 eV
Range across DFT structures

Energy Above Hull

0.126 eV/atom
Best (lowest) across sources

Stability

Above hull
2 DFT sources

Structures

21
3 databases, 5 space groups
Crystallography

Reported Structures

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

Space GroupCrystal SystemBand Gap (eV)E above hull (eV/atom)E/atom (eV)Density (g/cm³)
Cc (No. 9)monoclinic5.060.1256-8.7521.54
P1 (No. 1)triclinic5.140.1260-8.7511.51
Imm2 (No. 44)orthorhombic5.310.1392-8.7381.61
Cm (No. 8)monoclinic5.020.1691-8.7081.75
P1 (No. 1)triclinic1.230.7537-8.1242.14
Cm (No. 8)monoclinic0.060.9691-7.9082.40
P1 (No. 1)Triclinic1.56
Cc (No. 9)
Imm2 (No. 44)Orthorhombic1.61
P1 (No. 1)Triclinic1.52
Imm2 (No. 44)Orthorhombic1.62
Imm2 (No. 44)Orthorhombic1.61
Uses

Applications

Where Potassium cyanide is used.

Gold mining and extractionElectroplatingOrganic chemical synthesisMetal cleaning
Reference

Frequently Asked Questions

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

What is KCN?

Potassium cyanide is a highly reactive inorganic salt that functions as a potent chemical reagent in industrial and laboratory settings.

More questions
What is KCN used for?
Potassium cyanide (KCN) is used in gold mining and extraction, electroplating, organic chemical synthesis, and metal cleaning.
What is the band gap of KCN?
Potassium cyanide (KCN) has a DFT-computed band gap of 0.06–5.31 eV across 21 reported structures.
Is KCN a metal, semiconductor, or insulator?
With a wide band gap up to 5.31 eV it is an insulator / wide-band-gap material.
Is KCN thermodynamically stable?
Potassium cyanide (KCN) has a lowest energy above hull of 0.126 eV/atom (above hull).
What is the crystal structure of KCN?
The lowest-energy reported polymorph of Potassium cyanide (KCN) is monoclinic symmetry, space group Cc (No. 9).
What is the density of KCN?
The computed density of the ground-state structure of Potassium cyanide (KCN) is 1.54 g/cm³.
How many polymorphs of KCN are known?
21 structures of KCN are reported across 3 databases, spanning 5 distinct space groups.
What elements does KCN contain?
Potassium cyanide (KCN) contains C, K, and N (3 elements).
Where does the data for KCN come from?
KCN data is cross-referenced from materials_project, mpaloe, jarvis.
Comparison

How It Compares

As a standalone compound in this context, potassium cyanide serves as a primary example of a cyanide-based salt that exhibits significant structural polymorphism despite its thermodynamic instability.

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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