Caesium phosphide formula12/5/2023 ![]() For special purpose or colored tubes the halophosphor was mixed with small quantities of other phosphors, particularly in De-Luxe tubes with higher color rendering index for use in food market or art studio lighting. Sometimes some of the calcium was substituted with strontium giving narrower emission peaks. The antimony and manganese must be incorporated in the correct trace amounts if the product is to be fluorescent. The reaction used to create halophosphor is shown below. The amounts of the manganese and antimony activators vary between 0.05 and 0.5 mole percent. These alterations allowed phosphors for Warm White, White and Daylight tubes, (with corrected color temperatures of 2900, 41 K respectively), to be made. Replacement of some of the fluoride ions with chloride ions in the lattice caused a general shift of the emission bands to the longer wavelength red end of the spectrum. Addition of manganese-II produced a second broad peak to appear at the red end of the emission spectrum at the expense of the antimony peak, excitation energy being transferred from the antimony to the manganese by a non radiative process and making the emitted light appear less blue and more pink. The antimony-V acted as the primary activator and produced a broad blue emission. When irradiated with 253.7 nm mercury resonance radiation they fluoresced with broad emission which appeared within the range of acceptable whites. Synthetic fluorapatite doped with manganese-II and antimony-V formed the basis for the second generation of fluorescent tube phosphors referred to as halophosphors. The hydrogen fluoride byproduct is now one of the industrial sources of hydrofluoric acid, which in turn is used as a starting reagent for synthesis of a range of important industrial and pharmaceutical fluorine compounds. 3 Ca 2+įluorapatite as a naturally occurring impurity in apatite generates hydrogen fluoride as a byproduct during the production of phosphoric acid, as apatite is digested by sulfuric acid. This reaction is integral in the global phosphorus cycle. This material then reacts further with fluoride sources (often sodium monofluorophosphate or calcium fluoride (CaF 2)) to give the mineral. First, calcium phosphate is generated by combining calcium and phosphate salts at neutral pH. São Geraldo do Baixio, Doce valley, Minas Gerais, Brazil.įluorapatite can be synthesized in a three step process. ![]() Photomicrographs of thin section from Siilinjärvi apatite ore. Synthesis Fluorapatite grains in carbonate groundmass. Fluoroapatite has a mild bacteriostatic property as well, which helps decrease the proliferation of Streptococcus mutans, the predominant bacterium related to dental caries. The presence of fluorapatite helps prevent tooth decay or dental caries. It is also present in human teeth that have been exposed to fluoride ions, for example, through water fluoridation or by using fluoride-containing toothpaste. įluorapatite is found in the teeth of sharks and other fishes in varying concentrations. It occurs as a residual mineral in lateritic soils. It commonly occurs as a detrital or diagenic mineral in sedimentary rocks and is an essential component of phosphorite ore deposits. It occurs widely as an accessory mineral in igneous rocks and in calcium rich metamorphic rocks. Industrially, the mineral is an important source of both phosphoric and hydrofluoric acids.įluorapatite as a mineral is the most common phosphate mineral. Chlorapatite (Ca 5(PO 4) 3Cl) is another related structure. It is often combined as a solid solution with hydroxylapatite (Ca 5(PO 4) 3OH or Ca 10(PO 4) 6(OH) 2) in biological matrices. įluorapatite crystallizes in a hexagonal crystal system. Along with hydroxylapatite, it can be a component of tooth enamel, but for industrial use both minerals are mined in the form of phosphate rock, whose usual mineral composition is primarily fluorapatite but often with significant amounts of the other. Although samples can have various color (green, brown, blue, yellow, violet, or colorless), the pure mineral is colorless, as expected for a material lacking transition metals. Fluorapatite is a hard crystalline solid. Sea-green, violet, purple, blue, pink, yellow, brown, white, colorless, may be zonedįluorapatite, often with the alternate spelling of fluoroapatite, is a phosphate mineral with the formula Ca 5(PO 4) 3F (calcium fluorophosphate). JSTOR ( November 2013) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.
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