N

Non-stoichiometric Compound

Quick Reference
Also Known AsBerthollide compound, variable composition compound, defect compound, nonstoichiometric

What is Non-stoichiometric Compound?

A non-stoichiometric compound (or Berthollide compound) is a compound in which the ratio of elements is not a simple whole number. These compounds violate Dalton's Law of Definite Proportions. They occur mainly in transition metal oxides, sulfides, and other compounds where the metal can exist in multiple oxidation states, allowing variable compositions. Non-stoichiometry is responsible for important electronic and magnetic properties.

Properties & Characteristics

Variable element ratio (not a simple integer ratio). Common in: transition metal oxides (FeₓO, x≠1: wüstite), sulfides, hydrides. Defect structures: cation vacancies, anion vacancies, interstitial atoms. Example: iron(II) oxide (wüstite): Fe₀.₉₄₋₀.₉₉O. Properties: variable color, electrical conductivity, magnetism.

Uses & Applications

Semiconductor technology. Catalysis (nonstoichiometric oxides as catalysts). Battery materials (Li intercalation compounds). Corrosion understanding (iron oxides). Ceramic materials. Hydrogen storage (non-stoichiometric metal hydrides). Magnetic materials.

Safety Information

Safety depends on specific compound. Variable composition means properties may not be predicted from simple formulas. Non-stoichiometric transition metal oxides and sulfides have individual toxicity profiles.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Non-stoichiometric Compound
Synonyms Berthollide compound, variable composition compound, defect compound, nonstoichiometric

Frequently Asked Questions

A non-stoichiometric compound (or Berthollide compound) is a compound in which the ratio of elements is not a simple whole number. These compounds violate Dalton's Law of Definite Proportions. They occur mainly in transition metal oxides, sulfides, and other compounds where the metal can exist in multiple oxidation states, allowing variable compositions. Non-stoichiometry is responsible for important electronic and magnetic properties.

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