Zinc chromate (ZnCrO4) is a corrosion-resistant compound used in coatings and primers. It safeguards metals, like aircraft components, from rust and degradation, prolonging their lifespan and structural integrity.
| IUPAC Name | Zinc Chromate |
| Molecular Formula | ZnCrO4 |
| CAS Number | 13530-65-9 |
| Synonyms | Zinc Yellow, Zinc Yellow 36, Zinc Chromate(VI), Trizinc Dicitratotrichromate, Zinc tetroxychromate |
| InChI | InChI=1S/4Cr.3O.Zn/q;;;3*-1; |
Zinc Chromate Properties
Zinc Chromate Formula
The chemical formula of zinc tetroxychromate is ZnCrO4. It consists of one zinc (Zn) atom, one chromium (Cr) atom, and four oxygen (O) atoms.
Zinc Chromate Molar Mass
The molar mass of zinc tetroxychromate (ZnCrO4) is approximately 181.38 g/mol. It is calculated by adding the atomic masses of zinc, chromium, and oxygen present in the compound.
Zinc Chromate Boiling Point
Zinc tetroxychromate does not have a distinct boiling point because it decomposes before reaching its boiling point. Upon heating, it undergoes thermal decomposition, releasing toxic fumes.
Zinc Chromate Melting Point
Zinc tetroxychromate has a melting point of about 345°C (653°F). At this temperature, the solid compound transforms into a liquid state.
Zinc Chromate Density g/mL
The density of zinc tetroxychromate is around 3.18 g/mL. This value indicates the mass of the compound per unit volume and is often used to characterize its physical properties.
Zinc Chromate Molecular Weight
The molecular weight of zinc tetroxychromate is 181.38 g/mol. It represents the sum of the atomic weights of all the elements present in the compound’s chemical formula.
Zinc Chromate Structure
Zinc tetroxychromate typically adopts a tetragonal crystal structure. It consists of Zn2+ cations and CrO4^2- anions held together by electrostatic forces.
Zinc Chromate Solubility
Zinc tetroxychromate has limited solubility in water. It forms a colloidal suspension when mixed with water due to its low solubility. The compound’s solubility can vary with temperature and pH levels.
| Appearance | Yellow solid |
| Specific Gravity | 3.18 g/cm³ |
| Color | Yellow |
| Odor | Odorless |
| Molar Mass | 181.38 g/mol |
| Density | 3.18 g/mL |
| Melting Point | 345°C (653°F) |
| Boiling Point | Decomposes |
| Flash Point | Not applicable |
| Water Solubility | Limited |
| Solubility | Limited in water, soluble in acids |
| Vapour Pressure | Not significant |
| Vapour Density | Not applicable |
| pKa | Not applicable |
| pH | Basic |
Zinc Chromate Safety and Hazards
Zinc tetroxychromate poses significant safety hazards due to its toxic nature. Inhalation or ingestion can lead to respiratory and gastrointestinal issues. It’s a skin and eye irritant. Prolonged exposure can cause serious health problems. Adequate ventilation, protective clothing, and gear are essential when handling it. Disposal should follow regulations to prevent environmental harm. Safer alternatives are recommended due to its adverse health and environmental effects.
| Hazard Symbols | Irritant, Health Hazard |
| Safety Description | Toxic; Harmful if inhaled, swallowed, or in contact with skin/eyes. Avoid release to the environment. Use personal protective equipment. |
| UN IDs | UN1479 |
| HS Code | 3206.11.00 |
| Hazard Class | 6.1 (Toxic substances) |
| Packing Group | II (Moderate danger) |
| Toxicity | Can cause serious health effects upon exposure. Carcinogenic and harmful to aquatic life. Handle with caution and minimize exposure. |
Zinc Chromate Synthesis Methods
Zinc tetroxychromate can be synthesized through various methods. One common approach involves reacting zinc oxide (ZnO) and chromium trioxide (CrO3) in an aqueous solution. Zinc oxide dissolves to form zinc hydroxide, while chromium trioxide reacts to create chromic acid. These solutions are then mixed, leading to the formation of zinc tetroxychromate precipitates. The precipitates are then separated, washed, and dried to obtain the final product.
Another method involves the reaction between ZnSO4 and sodium chromate (Na2CrO4). These compounds are dissolved in water to form their respective ions. Mixing these solutions results in the precipitation of zinc tetroxychromate. The precipitate is collected, washed, and dried.
It’s crucial to conduct these synthesis processes in a controlled manner due to the toxic nature of the compounds involved. Additionally, appropriate safety measures and protective equipment are necessary to minimize exposure to the hazardous materials. These methods allow for the production of zinc tetroxychromate, which is used in various industrial applications despite its associated health and environmental concerns.
Zinc Chromate Uses
Zinc tetroxychromate is utilized in various applications due to its unique properties, despite its associated health and environmental concerns. Its uses include:
- Corrosion Inhibition: Zinc tetroxychromate serves as a corrosion inhibitor in coatings, primers, and paints for metals like steel and aluminum. It forms a protective layer that prevents oxidation and extends the lifespan of the metal.
- Aerospace Industry: The aerospace sector utilizes zinc tetroxychromate to shield aircraft components from corrosion. Its durability and resistance to extreme conditions make it suitable for aerospace coatings.
- Marine Coatings: In marine environments, where metals confront saltwater and humidity, zinc tetroxychromate coatings act as a shield, preventing rust and deterioration.
- Pigments and Dyes: Zinc tetroxychromate’s vibrant yellow hue finds utility in pigments and dyes for plastics, textiles, and artistic materials.
- Wood Preservatives: Zinc tetroxychromate safeguards against fungal decay and insect infestations in wood treatments, prolonging the life of wooden structures.
- Electroplating: Utilized in electroplating processes, zinc tetroxychromate imparts a protective and decorative layer to various metal objects.
- Automotive Industry: Zinc tetroxychromate finds a place in automotive coatings, offering protection against the elements and enhancing the visual appeal of vehicles.
- Corrosion Testing: Laboratories use it as a reference material to evaluate the corrosion resistance of materials and coatings.
- Industrial Primers: Industrial settings apply zinc tetroxychromate-containing primers on metal surfaces, providing a base layer for subsequent paint applications.
Questions:
Q: Where to buy zinc chromate primer?
A: Zinc tetroxychromate primer can be purchased from hardware stores, online retailers, and specialty coatings suppliers.
Q: Is zinc chromate soluble?
A: Zinc tetroxychromate has limited solubility in water, forming a colloidal suspension.
Q: What color is zinc chromate?
A: Zinc tetroxychromate is typically yellow in color.
Q: How long zinc chromate to dry?
A: The drying time of zinc tetroxychromate primer can vary but generally takes a few hours to dry to the touch.
Q: Will hysol stick to zinc chromate?
A: Yes, Hysol adhesives can adhere well to zinc tetroxychromate surfaces.
Q: Is it ok to touch zinc chromate?
A: It’s best to avoid direct contact with zinc tetroxychromate as it can be harmful due to its toxicity.
Q: Will West System epoxy adhere to zinc chromate primer?
A: Yes, West System epoxy is known to adhere effectively to properly prepared zinc tetroxychromate primers.
Q: What is the name of the compound with the formula ZnCrO4?
A: The compound with the formula ZnCrO4 is called zinc tetroxychromate.
Q: Is ZnCrO4 ionic or covalent?
A: ZnCrO4 is an ionic compound.
Q: Is ZnCrO4 soluble in water?
A: ZnCrO4 has limited solubility in water.
Q: Is ZnCrO4 ionic or molecular?
A: ZnCrO4 is an ionic compound.