Tantalate
Tantalates are chemical compounds containing an anion composed of tantalum and oxygen. They are typically salts containing the TaOxn- anion, where x is a variable number of oxygen atoms and n is the charge. The most common tantalates feature tantalum in its +5 oxidation state.
Tantalates are found in a variety of forms, including simple tantalates containing discrete TaO6 octahedra, and more complex tantalates with polymeric or extended network structures. These structures can significantly influence their properties.
Occurrence and Production:
Tantalates are naturally found in minerals such as tantalite-(Fe), tantalite-(Mn), and wodginite. These minerals are primary sources of tantalum. Tantalates are also produced synthetically through various chemical reactions, often involving tantalum pentoxide (Ta2O5) reacting with metal oxides at high temperatures.
Properties:
Tantalates often exhibit high melting points, chemical inertness, and dielectric properties. These properties make them useful in several applications. The specific properties of a tantalate will depend on its chemical composition and crystal structure.
Applications:
Tantalates find applications in:
- Electronics: Some tantalates, such as lithium tantalate (LiTaO3), are used in surface acoustic wave (SAW) devices, piezoelectric sensors, and nonlinear optics due to their piezoelectric and electro-optic properties. Tantalum pentoxide is a key component in tantalum capacitors.
- Catalysis: Certain tantalates are used as catalysts or catalyst supports in various chemical reactions.
- High-Temperature Applications: Due to their high melting points and chemical inertness, tantalates can be employed in high-temperature environments.
- Nuclear reactors: Some tantalates exhibit strong neutron absorption capability, finding use in nuclear control rods.
Examples:
- Lithium tantalate (LiTaO3)
- Barium tantalate (BaTa2O6)
- Tantalum pentoxide (Ta2O5) - although not strictly a tantalate salt, it is the precursor for many tantalates.
Safety:
While generally considered to be relatively inert, some tantalum compounds can pose health risks depending on the specific compound and route of exposure. Safety data sheets should be consulted for detailed information on the handling and potential hazards of specific tantalates.