![]() The structures of both forms consist of chains built from octahedral and pentagonal bipyramidal polyhedra sharing opposite vertices. The transition point between these two forms has been reported as 1360 ☌. The low temperature form is known as β-Ta 2O 5, and the high temperature form is known as α-Ta 2O 5. These reactions can be further modified to yield pure tantalum via stoichiometry, thermal control and electrolysis.īoth low and high temperature forms exist. ![]() Ta 2O 5 + 5CCl 4 → 2TaCl 5 + 5COCl 2 Ta 2O 5 can be reduced several different ways, including the use of metallic reductants such as calcium and aluminum. Ta 2O 5 can be chlorinated to become TaCl 5 by heating a mixture of tantalum pentoxide and tetrachlorocarbon in a sealed glass tube in a high pressure steel reaction vessel. This pure form of tantalum is then exposed to oxygen at temperatures above 1000 degrees Celsius, to form Ta 2O 5. Once K 2TaF 7 has been isolated, Ta can be extracted by the electrolysis of molten K 2TaF 7. The salts can be separated by a liquid-liquid extraction process, using various ketones as the liquids. The mixed acids are dissolved by passing anhydrous hydrofluoric acid into the slurry and adding the stoichiometric quantity of potassium fluoride to yield a salt. One method involves isolating tantalum pentoxide by crushing a concentrate of the mineral columbite-tantalite and fusing the powdered mineral with sodium hydroxide to give a slurry of mixed insoluble niobic and tantalic acids. There are several methods available for the syntesis of tantalum oxide. Microlite contains approximately 70% of tantalum oxide, and pyrochlore contains approximately 10%. The microlite-pyrochlore mineral series is also a source of tantalum oxide. The metal oxide discovered by Ekeberg was obtained from minerals taken from pegmatite (an igneous rock associated with tantalite or columbite) at Ytterby, Sweden, and Kimoto, Finland. Materials to avoid when dealing with tantalum pentoxide are strong oxidizing agents, chlorine trifluoride, bromine monofluoride, lithium and acids. It can be synthesized by hydrolysis of its alkoxide:Ģ Ta(OCH 2CH 3) 5 + 5 H 2O → Ta 2O 5 + 10 HOCH 2CH 3 Due to its high index of refraction, Ta 2O 5 has been utilized in the fabrication of the glass of many photographic lenses. There is still some interest to use it in MIM capacitors for RF CMOS integrated circuits. Subsequently in the 2000s, this strong interest has dropped very significantly. ![]() ![]() For example, Elpida Memory (a Japanese company making DRAM) has put in a strong effort to improve ultrathin tantalum oxide films for DRAM applications. In the 1990s, there was a very strong interest to do research on tantalum oxide as a high-k dielectric for DRAM capacitor applications. Ta 2O 5 is used to make capacitors in automotive electronics, cell phones, and pagers, electronic circuitry thin-film components and high-speed tools. Ta 2O 5 is a high refractive index, low absorption material useful for coatings in the near- UV to IR spectra regions it decomposes only at temperatures >1470 ☌. Both orthorhombic and hexagonal phases are known. Tantalum pentoxide is Ta 2O 5, also known as tantalum(V) oxide.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |