Gold oxide (Au2O3) is a compound formed by gold and oxygen. It exhibits properties that differ from metallic gold, making it of interest in various scientific and industrial applications.
| IUPAC Name | Gold(III) oxide |
| Molecular Formula | Au2O3 |
| CAS Number | 1303-58-8 |
| Synonyms | Auric oxide, Gold sesquioxide, Gold trioxide, Digold trioxide |
| InChI | InChI=1S/2Au.3O |
Gold (III) Oxide Properties
Gold Oxide Formula
The formula of gold trioxide is Au2O3. It is composed of two atoms of gold and three atoms of oxygen. This chemical formula indicates the ratio of elements in the compound.
Gold Oxide Molar Mass
The molar mass of gold trioxide (Au2O3) can be calculated by adding the atomic masses of its constituent elements. The molar mass of gold (Au) is 196.97 g/mol, and oxygen (O) is 16.00 g/mol. Thus, the molar mass of Au2O3 is approximately 441.97 g/mol.
Gold Oxide Boiling Point
Gold trioxide does not have a distinct boiling point since it undergoes decomposition before reaching a boiling state. When heated, it breaks down into its constituent elements.
Gold Oxide Melting Point
Gold trioxide has a melting point of around 1600°C (2912°F). At this temperature, the solid gold trioxide transitions into a liquid state, facilitating various applications in high-temperature processes.
Gold Oxide Density g/mL
The density of gold trioxide is approximately 11.34 g/mL. This value indicates its mass per unit volume and signifies its high density relative to many other materials.
Gold Oxide Molecular Weight
The molecular weight of gold trioxide (Au2O3) is approximately 441.97 g/mol. This value represents the sum of the atomic weights of all the atoms in one molecule of the compound.
Gold Oxide Structure
Gold trioxide (Au2O3) possesses a complex crystal structure. It exhibits a rhombohedral lattice arrangement, with gold and oxygen atoms forming specific patterns within the crystal lattice.
Gold Oxide Solubility
Gold trioxide (Au2O3) is generally insoluble in water and most organic solvents. It displays low solubility, meaning only minute amounts will dissolve, leading to its often-low reactivity in aqueous solutions.
| Appearance | Solid |
| Specific Gravity | N/A |
| Color | Black or brownish-black |
| Odor | Odorless |
| Molar Mass | 441.97 g/mol |
| Density | 11.34 g/mL |
| Melting Point | 1600°C (2912°F) |
| Boiling Point | Decomposes |
| Flash Point | N/A |
| Water Solubility | Insoluble |
| Solubility | low reactivity in aqueous solutions |
| Vapour Pressure | N/A |
| Vapour Density | N/A |
| pKa | N/A |
| pH | N/A |
Gold Oxide Safety and Hazards
Gold trioxide poses several safety and hazard considerations. It can be an irritant if it comes into contact with the skin, eyes, or respiratory system. Proper protective equipment, such as gloves and goggles, should be used during handling. Additionally, gold trioxide is not suitable for ingestion or inhalation, as it may cause adverse health effects. When working with this compound, ensure good ventilation to minimize the risk of exposure to its dust or fumes. Furthermore, in case of accidental ingestion or exposure, seek immediate medical attention. Proper storage and handling practices are essential to ensure the safe use of gold trioxide in laboratories and industrial settings.
| Hazard Symbols | Irritant |
| Safety Description | Irritant, Avoid Inhalation, Skin corrosion, Serious eye damage |
| UN IDs | N/A |
| HS Code | N/A |
| Hazard Class | N/A |
| Packing Group | N/A |
| Toxicity | Low |
Please note that some properties, such as UN IDs, HS Code, Hazard Class, and Packing Group, may not be applicable or not well-defined for Gold Oxide.
Gold Oxide Synthesis Methods
Various methods enable the synthesis of gold trioxide.
One common approach involves the reaction of gold metal with ozone gas at elevated temperatures. During this process, the gold metal reacts with ozone to form gold trioxide. Another method includes the thermal decomposition of gold salts, such as gold nitrate or gold hydroxide. When heated, these compounds break down, yielding gold trioxide as one of the products.
One can prepare gold trioxide through precipitation. This involves mixing a gold salt solution with a suitable precipitating agent, such as an alkali metal hydroxide, NaOH. Subsequently, further processing of the resulting precipitate yields pure gold trioxide.
Moreover, electrolysis of a gold-containing electrolyte can lead to the formation of gold trioxide on the anode surface. This method is particularly useful for producing thin films of gold trioxide.
Researchers may choose a specific synthesis method depending on factors such as the desired purity, particle size, and application of the gold trioxide. Careful control of reaction conditions is essential to achieve the desired product with optimal properties for specific uses.
Gold Oxide Uses
Gold trioxide finds various applications due to its unique properties. Here are its uses:
- Catalysis: Gold trioxide acts as a catalyst in certain chemical reactions, including the oxidation of carbon monoxide and other hydrocarbons. It is valuable in industrial processes for its catalytic efficiency.
- Glass Coloration: Gold trioxide imparts a characteristic red color to glass, making it useful for decorative purposes and creating stained glass art.
- Research: Scientists use gold trioxide in various research studies, including catalysis research, material science, and nanotechnology investigations.
- Photocatalysis: Gold trioxide exhibits photocatalytic properties, enabling the degradation of organic pollutants in water and air when exposed to light.
- Fuel Cells: Gold trioxide serves as a catalyst in fuel cells, enhancing the electrochemical reactions and improving their efficiency.
- Chemical Synthesis: Gold trioxide facilitates the synthesis of other gold compounds, like gold nanoparticles, which find applications in diverse fields.
- Medicine: Researchers have explored potential medical applications of gold trioxide, including cancer treatment and its antimicrobial properties.
- Sensor Technology: Manufacturers utilize gold trioxide-based sensors in gas sensing devices, environmental monitoring, and the detection of hazardous substances.
- Electronics: Manufacturers employ thin films of gold trioxide in electronics, such as in fabricating semiconductors and resistors, owing to its high melting point and stability.
- Nanotechnology: In nanotechnology, researchers employ gold trioxide nanoparticles as promising materials for drug delivery systems and medical diagnostics, thanks to their biocompatibility.
These applications demonstrate the versatility and significance of gold trioxide across various industries, contributing to advancements in technology, science, and healthcare.
Questions:
Q: What is the oxidation number of Au in Au2O3?
A: The oxidation number of Au in Au2O3 is +3.
Q: What volume of O2 at STP is produced from the reaction of 212 grams of Au2O3?
A: Approximately 160.7 liters of O2 at STP will be produced from the reaction of 212 grams of Au2O3.
Q: What is the use for Au2O3?
A: Au2O3 has applications as a catalyst, in electronics, nanotechnology, glass coloration, and research studies.
Q: How many grams of gold will there be in a metric ton (1000 kg) of Au2O3?
A: There will be approximately 432.09 grams of gold in a metric ton (1000 kg) of Au2O3.
Q: How many grams of gold will be in a ton of Au2O3?
A: There will be approximately 432,090 grams of gold in a ton of Au2O3.
Q: Is gold (III) oxide ionic or molecular?
A: Gold (III) oxide (Au2O3) is an ionic compound.
Q: What is the use of gold (III) oxide?
A: Gold (III) oxide is used in catalysis, electronics, nanotechnology, glass coloration, and fuel cell applications.
Q: What is the chemical formula for gold (III) oxide?
A: The chemical formula for Gold (III) oxide is Au2O3.