|
Hafnium Tetrafluoride
Hafnium tetrafluoride is the inorganic compound with the formula HfF4. It is a white solid. It adopts the same structure as zirconium tetrafluoride Zirconium(IV) fluoride (Zirconium, ZrFluorine, F4) is an inorganic chemical compound. It is a component of ZBLAN fluoride glass. It is insoluble in water. It is the main component of fluorozirconate glasses. Three crystalline phases of ZrF4 have ..., with 8-coordinate Hf(IV) centers. References Further reading *Benjamin, S. L., Levason, W., Pugh, D., Reid, G., Zhang, W., "Preparation and structures of coordination complexes of the very hard Lewis acids ZrF4 and HfF4", Dalton Transactions 2012, 41, 12548. Hafnium compounds Fluorides Metal halides {{Inorganic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoclinic
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic system. They form a parallelogram prism. Hence two pairs of vectors are perpendicular (meet at right angles), while the third pair makes an angle other than 90°. Bravais lattices Two monoclinic Bravais lattices exist: the primitive monoclinic and the base-centered monoclinic. For the base-centered monoclinic lattice, the primitive cell has the shape of an oblique rhombic prism;See , row mC, column Primitive, where the cell parameters are given as a1 = a2, α = β it can be constructed because the two-dimensional centered rectangular base layer can also be described with primitive rhombic axes. Note that the length a of the primitive cell below equals \frac \sqrt of the conventional cell above. Crystal classes The table below org ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pearson Symbol
The Pearson symbol, or Pearson notation, is used in crystallography as a means of describing a crystal structure, and was originated by W. B. Pearson. The symbol is made up of two letters followed by a number. For example: * Diamond structure, ''cF''8 * Rutile structure, ''tP''6 The two (italicised) letters specify the Bravais lattice. The lower-case letter specifies the crystal family, and the upper-case letter the centering type. The number at the end of the Pearson symbol gives the number of the atoms in the conventional unit cell.Nomenclature of Inorganic Chemistry IUPAC Recommendations 2005 IR-3.4.4, pp. 49–51; IR-11.5, pp. 241–242. |
Hafnium(IV) Chloride
Hafnium(IV) chloride is the inorganic compound with the formula HfCl4. This colourless solid is the precursor to most hafnium organometallic compounds. It has a variety of highly specialized applications, mainly in materials science and as a catalyst. Preparation HfCl4 can be produced by several related procedures: *The reaction of carbon tetrachloride and hafnium oxide at above 450 °C; :HfO2 + 2 CCl4 → HfCl4 + 2 COCl2 *Chlorination of a mixture of HfO2 and carbon above 600 °C using chlorine gas or sulfur monochloride: :HfO2 + 2 Cl2 + C → HfCl4 + CO2 *Chlorination of hafnium carbide above 250 °C. Separation of Zr and Hf Hafnium and zirconium occur together in minerals such as zircon, cyrtolite and baddeleyite. Zircon contains 0.05% to 2.0% hafnium dioxide HfO2, cyrtolite with 5.5% to 17% HfO2 and baddeleyite contains 1.0 to 1.8 percent HfO2.Newnham, Ivan Edgar "Purification of Hafnium Tetrachloride". November 22, 1960. Hafnium and zircon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titanium(IV) Fluoride
Titanium(IV) fluoride is the inorganic compound with the formula Ti F4. It is a white hygroscopic solid. In contrast to the other tetrahalides of titanium, it adopts a polymeric structure. In common with the other tetrahalides, TiF4 is a strong Lewis acid. Preparation, structure, reactions The traditional method involves treatment of titanium tetrachloride with excess hydrogen fluoride: :TiCl4 + 4 HF → TiF4 + 4 HCl Purification is by sublimation, which involves reversible cracking of the polymeric structure. X-ray crystallography reveals that the Ti centres are octahedral, but conjoined in an unusual columnar structure. TiF4 forms adducts with many ligands. One example is ''cis''-TiF4(MeCN)2, which is formed by treatment with acetonitrile Acetonitrile, often abbreviated MeCN (methyl cyanide), is the chemical compound with the formula and structure . This colourless liquid is the simplest organic nitrile (hydrogen cyanide is a simpler nitrile, but the cyanide anion is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inorganic Compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemistry''. Inorganic compounds comprise most of the Earth's crust, although the compositions of the deep mantle remain active areas of investigation. Some simple carbon compounds are often considered inorganic. Examples include the allotropes of carbon (graphite, diamond, buckminsterfullerene, etc.), carbon monoxide, carbon dioxide, carbides, and the following salts of inorganic anions: carbonates, cyanides, cyanates, and thiocyanates. Many of these are normal parts of mostly organic systems, including organisms; describing a chemical as inorganic does not necessarily mean that it does not occur within living things. History Friedrich Wöhler's conversion of ammonium cyanate into urea in 1828 is often cited as the starting point of modern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zirconium Tetrafluoride
Zirconium(IV) fluoride ( Zr F4) is an inorganic chemical compound. It is a component of ZBLAN fluoride glass. It is insoluble in water. It is the main component of fluorozirconate glasses. Three crystalline phases of ZrF4 have been reported, α (monoclinic), β (tetragonal, Pearson symbol tP40, space group P42/m, No 84) and γ (unknown structure). β and γ phases are unstable and irreversibly transform into the α phase at 400 °C. Zirconium fluoride is used as a zirconium source in oxygen-sensitive applications, e.g. metal production. Zirconium fluoride can be purified by distillation or sublimation. Conditions/substances to avoid are: moisture, active metals, acids and oxidizing agents. Zirconium fluoride in a mixture with other fluorides is a coolant for molten salt reactors. In the mixture with sodium fluoride it is a candidate coolant for the Advanced High-Temperature Reactor. Together with uranium salt, zirconium fluoride can be a component of fuel-coolant in molt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hafnium Compounds
Hafnium compounds are compounds containing the element hafnium (Hf). Due to the lanthanide contraction, the ionic radius of hafnium(IV) (0.78 ångström) is almost the same as that of zirconium(IV) (0.79 angstroms). Consequently, compounds of hafnium(IV) and zirconium(IV) have very similar chemical and physical properties. Hafnium and zirconium tend to occur together in nature and the similarity of their ionic radii makes their chemical separation rather difficult. Hafnium tends to form inorganic compounds in the oxidation state of +4. Halogens react with it to form hafnium tetrahalides. At higher temperatures, hafnium reacts with oxygen, nitrogen, carbon, boron, sulfur, and silicon. Some compounds of hafnium in lower oxidation states are known. Halides Hafnium(IV) fluoride (HfF4) is a white crystalline powder. It has a monoclinic crystal structure, with space group C2/c (No.15), and lattice constants ''a'' = 1.17 nm, ''b'' = 0.986 nm and ''c'' = 0.764 nm. Hafnium(IV) c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorides
Fluoride (). According to this source, is a possible pronunciation in British English. is an inorganic, monatomic anion of fluorine, with the chemical formula (also written ), whose salts are typically white or colorless. Fluoride salts typically have distinctive bitter tastes, and are odorless. Its salts and minerals are important chemical reagents and industrial chemicals, mainly used in the production of hydrogen fluoride for fluorocarbons. Fluoride is classified as a weak base since it only partially associates in solution, but concentrated fluoride is corrosive and can attack the skin. Fluoride is the simplest fluorine anion. In terms of charge and size, the fluoride ion resembles the hydroxide ion. Fluoride ions occur on Earth in several minerals, particularly fluorite, but are present only in trace quantities in bodies of water in nature. Nomenclature Fluorides include compounds that contain ionic fluoride and those in which fluoride does not dissociate. The nomenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_oxide.jpg "Click for more on -> Hafnium Compounds")
_1.JPG "Click for more on -> Fluorides")