Hexagonal tungsten trioxide (hex-WO₃) exhibits unique physical properties that support its use in various applications. Here are its key characteristics:
- Crystal Structure of Hexagonal Tungsten Trioxide
- Crystal System and Space Group: Hexagonal tungsten trioxide belongs to the hexagonal crystal system with point group 6/mmm and space group P63/mmc. This structure contributes to its high density and stability.
- Lattice Parameters: With lattice parameters a = b = 3.160Å, c = 12.248Å, the hexagonal structure features alternating W and O atoms in a tightly packed hexagonal arrangement.
- Color and Appearance
- Color: At room temperature, hex-WO₃ is typically a pale yellow. When heated, the color may deepen, returning to pale yellow upon cooling. In electrochromic applications, hex-WO₃ turns a deep blue when tinted, making it ideal for smart windows and automotive mirrors.
- Form: Hex-WO₃ is often found as a powder or thin film, with the exact form depending on its synthesis method and application requirements.
- Optical Properties
- Light Absorption and Transmission: Hex-WO₃ exhibits high refractive indices and transmittance in the visible and UV range, supporting its use in optical and optoelectronic devices. Its light absorption and transmission characteristics are closely linked to its crystal structure and surface properties.
- Photochromic Behavior: Hex-WO₃ has photochromic properties, allowing it to change color upon exposure to light. Discovered in 1969, this property has led to applications in smart windows and electrochromic devices, where the material turns a soft, deep blue when tinted, offering light-blocking benefits.
- Thermal Properties
- Melting and Boiling Points: Hex-WO₃ has a high melting point (~1473°C) and boiling point (>1750°C), enabling it to maintain stable physical and chemical properties in high-temperature environments.
- Thermal Stability: It exhibits excellent thermal stability, resisting decomposition or phase changes at high temperatures, making it suitable for applications like high-temperature catalysis and thermoelectric conversion.
- Additional Physical Properties
- Density: Hex-WO₃ has a relatively high density due to its densely packed hexagonal crystal structure.
- Conductivity: As an n-type semiconductor, hex-WO₃ has notable conductivity, though this may vary based on crystal structure, dopants, and processing techniques.
- Specific Surface Area: At the nanoscale, hex-WO₃ has a high specific surface area and small particle size, enhancing its catalytic performance, which is also influenced by its crystal structure and preparation methods.
Hexagonal tungsten trioxide’s combination of unique crystal structure, optical, thermal, and conductive properties supports its broad use in optoelectronics, energy storage, catalysis, sensors, and thermoelectric materials. Its potential is likely to expand further as scientific and technological advances continue.
More details of tungsten oxide product, please visit website: tungsten-oxide.com
Please contact CHINATUNGSTEN for inquiry and order of tungsten oxide:
Email: sales@chinatungsten.com
Tel.: 86 592 5129595
