Chromium(III) oxide

• CAS: 1308-38-9
• Catalog Number: ACM1308389-1
• Category: Main Products
• Molecular Weight: 151.99
• Molecular Formula: Cr2O3
• Synonyms: Chromium sesquioxide
• IUPAC Name: Oxo(oxochromiooxy)chromium
• Canonical SMILES: O=[Cr]O[Cr]=O
• InChI: InChI=1S/2Cr.3O
• InChI Key: QDOXWKRWXJOMAK-UHFFFAOYSA-N
• Boiling Point: 4000 °C
• Melting Point: 2435 °C
• Flash Point: 3000 °C
• Density: 5.22 g/cm3
• Solubility: Insoluble in all solvents
• Storage: Room Temperature
• Complexity: 34.2
• Covalently-Bonded Unit Count: 1
• Exact Mass: 151.865753
• Heavy Atom Count: 5
• Monoisotopic Mass: 151.865753
• Physical State: Pale to dark green powder
• Topological Polar Surface Area: 43.4 Ų

Case Study

Chromium(III) Oxide for the Synthesis of Nanoparticles as Redox Catalysts for Hydrogen Peroxide Detection

Uzunboy S, et al. Microchemical Journal, 2022, Volume 178, 107335.

In this case study, we explore the Cr₂O₃ NP-based colorimetric method for H₂O₂ detection, which demonstrates higher selectivity compared to conventional nanosensing techniques employing Au/Ag nanoparticles.
Synthesis of Cr₂O₃ Nanoparticles
The synthesis of Cr₂O₃ NPs involves the use of chromium(III) nitrate nonahydrate [Cr(NO₃)₃·9H₂O] in an ethanol medium, with the pH adjusted to 8.0 using ammonia solution. The resulting suspension undergoes centrifugation, washing, and drying in a vacuum oven to yield the desired nanoparticles. These particles are then dispersed in distilled water for use in subsequent catalytic applications.
Application in Hydrogen Peroxide Detection
The Cr₂O₃ NP-based method for H₂O₂ determination is based on the redox cycling of Cr(III) and Cr(VI). When H₂O₂ is introduced to Cr₂O₃ NPs under alkaline conditions (pH 10), Cr(III) is oxidized to Cr(VI). The generated Cr(VI) reacts with diphenylcarbazide (DPC) under acidic conditions to form a pink-colored complex. The intensity of the pink color, measured spectrophotometrically at 542 nm, is directly proportional to the H₂O₂ concentration. The method exhibits a linear calibration range from 4.0 to 58 µM, with high selectivity and compatibility with standard colorimetric methods.

Chromium(III) Oxide for the Synthesis of Chromium(III) Oxide/Silicon Carbide Coatings for Enhancing Hydrogen Permeation Resistance in Nickel-Iron Alloys

Zhou Q, et al. Fusion Engineering and Design, 2019, 143, 137-146.

Chromium(III) oxide (Cr₂O₃) is widely known for its excellent corrosion resistance and high-temperature stability. This case study focuses on a Cr₂O₃/Silicon Carbide (SiC) composite coating designed to improve the hydrogen permeation resistance of nickel-iron alloys, which are commonly used in environments such as fusion reactors.
Synthesis of Cr₂O₃/SiC Composite Coating: The composite coating was synthesized using pulse electrodeposition from a trivalent chromium bath, selected for its environmental benefits over hexavalent chromium baths. The bath composition included CrCl₃ as the chromium source, with additives like ammonium formate, sodium acetate, and boric acid for stabilization and pH control. Silicon carbide (SiC) nanoparticles, averaging 50 nm in diameter, were suspended in the electrolyte to be co-deposited with Cr³⁺ ions, producing a Cr₂O₃/SiC composite layer.
Oxidation and Crystallization: After the electrodeposition process, the sample was oxidized at 500°C and 100 Pa air pressure. This step allowed for the crystallization of the Cr₂O₃ phase, forming a dense oxide coating. The inclusion of SiC within the Cr₂O₃ matrix enhanced the mechanical properties of the film, making it more resistant to hydrogen diffusion.

The Influence of Lysozyme on the Stability and Electrokinetic Properties of Chromium(III) Oxide Suspensions

Szewczuk-Karpisz K, et al. Applied Surface Science, 2015, 347, 491-498.

This case study explores how lysozyme adsorption affects the electrokinetic properties and stability of Chromium(III) oxide (Cr₂O₃) suspensions under varying pH conditions, with implications for applications in biotechnology and environmental systems.
Lysozyme, a positively charged macromolecule at neutral pH, interacts with the negatively charged Cr₂O₃ surface through electrostatic attraction. When LSZ is added to Cr₂O₃ suspensions, it reduces the surface charge density of the particles, indicating adsorption on the oxide surface. At concentrations above 50 ppm, LSZ fully covers the Cr₂O₃ particles, as shown by the stabilization of the zeta potential. This interaction is dependent on the pH, with the strongest effects observed at pH 7.6 and 9, where LSZ adsorption significantly alters the surface electrokinetic properties of the Cr₂O₃ particles.
The stability of Cr₂O₃ suspensions in the presence of lysozyme is highly pH-dependent. At acidic pH values (3 and 4.6), despite the lack of significant adsorption, the suspension stability increases, likely due to depletion stabilization mechanisms. At pH 7.6, where LSZ adsorption is high, electrostatic stabilization occurs, enhancing the suspension's stability. However, at pH 9, the system experiences a slight destabilization due to charge neutralization, where the LSZ macromolecules reduce the surface charge of the Cr₂O₃ particles, leading to less repulsion between them.
The presence of lysozyme significantly influences the electrokinetic properties and stability of Chromium(III) oxide suspensions.

Chromium(III) Oxide for the Preparation of Hybrid Pigments for Multi-Band Stealth Coatings

Chai X, et al. Composites Science and Technology, 2021, 216, 109038.

The objective of this study was to modify Cr₂O₃ with silver (Ag) to create Cr₂O₃@Ag hybrid pigments that enhance the multi-band stealth performance, including visual, infrared, and radar stealth capabilities.
Modification Strategy:
The Cr₂O₃ powders underwent a sensitization process, followed by an electroless silver plating technique to deposit Ag particles onto the surface. The silver-modified Cr₂O₃ pigments were then integrated into silicone resin to form a coating, which displayed a remarkable reduction in emissivity and increased radar wave transmission. The Cr₂O₃@Ag hybrid coating achieved a low emissivity of 0.760 at 65 wt% Ag content, while maintaining radar wave transmittance over 90% at a coating thickness of 0.3 mm.
Mechanism and Performance:
The stealth performance of the Cr₂O₃@Ag coating is attributed to the electrical conductivity enhancement from the silver deposition, reducing emissivity while maintaining low radar reflectivity. Impedance matching between Cr₂O₃ and free space, aided by the Ag particles' spacing, was crucial for high radar transmittance. Furthermore, the brownish-green color of Cr₂O₃@Ag effectively lowered visible and near-infrared reflectance compared to pure Cr₂O₃, making it suitable for multi-band camouflage.

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Custom Q&A

What is the Molecular formula of Chromium(III) oxide?

Cr2O3

What is the Molecular weight of Chromium(III) oxide?

151.99

What is the EC number of Chromium(III) oxide?

215-160-9

What is the InChIKey of Chromium(III) oxide?

QDOXWKRWXJOMAK-UHFFFAOYSA-N

What is the SMILES of Chromium(III) oxide?

O=[Cr]O[Cr]=O

What is the Appearance of Chromium(III) oxide?

Pale to dark green powder

What is the Melting point of Chromium(III) oxide?

2435℃

What is the Solubility of Chromium(III) oxide?

Its insoluble in all solvents

What is the Description of Chromium(III) oxide?

Chromium(III) oxide is an oxide of chromium that occurs in nature as the rare mineral eskolaite. It is commonly used as pigment, under the name viridian, in paints, inks, and glasses.

What is the Density of Chromium(III) oxide?

5.22 g/mL