Tellurite
Tellurite refers to several different concepts, broadly related to the element tellurium (Te). This entry will cover the primary meanings:
1. Mineralogy:
In mineralogy, a tellurite is a mineral containing the tellurite anion (TeO32-). These minerals are generally rare and often secondary minerals formed by the oxidation of tellurides. They can occur in various colors and crystal habits, depending on the specific mineral and its chemical composition. Some notable tellurite minerals include:
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Tellurite (Mineral): The mineral tellurite is a dimorph of paratellurite and is the oxide form of tellurium (TeO2). It's typically found as white or yellowish orthorhombic crystals.
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Denningite: A tellurite mineral with the formula (Mn,Zn)Te2O5Cl2.
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Emmonsite: A hydrated copper tellurite mineral, CuFe2(TeO3)3·2H2O.
The presence of tellurite minerals is often an indicator of specific geological conditions conducive to tellurium enrichment.
2. Chemistry:
In chemistry, a tellurite is a salt or ester of tellurous acid (H2TeO3). Tellurites contain the tellurite anion, TeO32-. These compounds have applications in various areas, including:
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Microbiology: Potassium tellurite (K2TeO3) is frequently used in selective growth media for certain bacteria, particularly Corynebacterium diphtheriae. The tellurite is reduced by the bacteria, resulting in the formation of black colonies due to the deposition of tellurium metal.
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Catalysis: Tellurite compounds can be used as catalysts in certain chemical reactions.
3. Materials Science:
Tellurite glasses are a class of optical materials characterized by their high refractive index and nonlinear optical properties. These glasses are based on tellurium dioxide (TeO2) and are doped with other oxides to modify their properties. They have potential applications in:
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Optical fibers: Due to their ability to transmit light in the near-infrared region.
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Optical amplifiers: For signal boosting in optical communication systems.
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Nonlinear optics: For applications such as frequency conversion.
In summary, "tellurite" has distinct meanings depending on the context, encompassing specific minerals, chemical compounds, and specialized glass materials, all linked by the presence of the element tellurium.