Calcium fluoride halide

Many ionic halides dissolve in water to give hydrated ions. The solubility of a given halide depends on several factors, and generalisations are difficult. Ionic fluorides, however, often differ from other halides in solubility. For example, calcium fluoride is insoluble but the other halides of calcium are highly soluble silver fluoride. AgF, is very soluble but the other silver halides are insoluble. 

Due to the above requirements, typical optically-transparent materials, such as oxides (glass, quartz, alumina, zirconium oxide etc.) and halides (sodium chloride, lithium fluoride, calcium fluoride, potassium bromide, cesium bromide etc.) are usually unsuitable for use with fluoride melts. Therefore, no standard procedure exists at present for the spectral investigation of fluoride melts, and an original apparatus must be created especially for each particular case. 

The boron halides are made either by direct reaction of the elements at a high temperature or from boron oxide. The most important is boron trifluoride, BF, an industrial catalyst produced by the reaction between boron oxide, calcium fluoride, and sulfuric acid ... 

Goldschmidt predicted from his empirical rule that calcium chloride would not have the fluorite structure, and he states that on investigation he has actually found it not to crystallize in the cubic system. Our theoretical deduction of the transition radius ratio allows us to predict that of the halides of magnesium, calcium, strontium and barium only calcium fluoride, strontium fluoride and chloride, and barium fluoride, chloride,... 

Halides Metal ion(s) + halogen ion Common salt (sodium chloride), a component of animal diets Fluorite (calcium fluoride), a lapidary material and flux... 

Sulfuric acid reacts with metal halides to form hydrogen halides. Thus, hydrogen fluoride is commercially made by the action of calcium fluoride with the acid ... 

The electrical conductivities of soln. of a great many compounds in liquid hydrogen halides have been measured by E. H. Archibald and D. McIntosh. The conductivity is raised considerably by phosphoryl chloride. Sodium sodium sulphide, borate, phosphate, nitrate, thiosulphate, and arsenate chromic anhydride potassium nitrate, hydroxide, chromate, sulphide, bisulphate, and ferro- and ferri- cyanide ammonium fluoride and carbonate j rubidium and caesium chloride magnesium sulphate calcium fluoride ... 

Three oxide halides T10X (X = F, Cl, Br) are known.1 Preparations must be carried out at low temperatures1 387 since the heavier oxyhalides in particular readily decompose. There is no structural information on either TlOCl br TlOBr, but X-ray crystallography shows that TlOF has a calcium fluoride structure, with Tl3+ ions in a cube of F" or 02 ions.388... 

Beryllium reacts with fused alkali halides releasing the alkali metal until an equilibrium is established. It does not react with fused halides of the alkaline-earth metals to release the alkaline-earth metal. Water-insoluble fluoroberyllates, however, are formed in a fused-salt system whenever barium or calcium fluoride is present. Beryllium reduces halides of aluminum and heavier elements. Alkaline-earth metals can be used effectively to reduce beryllium from its halides, but the use of alkaline-earths other than magnesium [7439-95 4] is economically unattractive because of the formation of water-insoluble fluoroberyllates. Formation of these fluorides precludes efficient recovery of the unreduced beryllium from the reaction products in subsequent processing operations. 

Calcium fluoride has also been used in metathetical reactions. Usually, heat is required to promote reactions of this type. Booth and Dutton4 passed vapors of a volatile halide [phosphorus(V) oxychloride] over a bed of heated calcium fluoride to produce the chlorofluoride and fluoride derivatives. Sodium fluoride, potassium fluoride, titanium (IV) fluoride, and zinc fluoride have been used in similar metathetical fluorination reactions. 

Much early work [21] involved the use of silver(I) fluoride, conveniently prepared from the oxide or carbonate with 40% hydrogen fluoride, for the exchange of single halogen atoms in alkyl halides [22] and other systems [23]. The use of calcium fluoride as a solid, inert support may increase the reactivity of silver fluoride [24] (Figure 3.1). 

At 500°C, phosphoryl chloride can be obtained by heating the pentoxide with rock salt (4.57), and if calcium fluoride is added, mixed phosphoryl halides are produced together with calcium metaphosphate (4.58). With calcium fluoride alone, phosphoruspentaflnoride is obtained (4.244). Metaphosphates are also produced by heating with sodium carbonate under anhydrous conditions (4.59). 

Boron trifluoride BF3 is the most important halide of boron. It is prepared starting from boron trioxide or borax by heating with a mixture of calcium fluoride and concentrated sulphuric acid. 

Latex emulsions, containing water, are best handled with either barium or calcium fluoride, or silver halide windows, or with an ATR accessory (see later). It is important to ensure that separation does not occur at the window or the IRE interface. Also, care must be exercised with materials that contain ammonia—at high concentration this will etch many of the window materials. 

The materials that have found particular application for gamma-ray measurements are all inorganic crystals sodium iodide (Nal), caesium iodide (Csl), calcium fluoride (CaF2), bismuth germanate (BGO) and, recently, lanthanum halides. Of these, the first is the most important and the last are materials rapidly gaining in importance. 

Only one calcium halide is known to have been used as a pigment, die calcium fluoride mineral fluorite q.v.). However, it has been suggested that bone (widely known as a pigment and used eidier as a white calcination product or a black coke) is to be considered a fluorinated calcium phosphate, fluorapatite (qq.v.). 

The boron halides have the expected formula, BX3. Boron trifluoride can be made by heating boric oxide, calcium fluoride and concentrated sulfuric acid ... 

Thorium metal also can he prepared hy thermal reduction of its hahdes with calcium, magnesium, sodium, or potassium at elevated temperatures (950°C), first in an inert atmosphere and then in vacuum. Fluoride and chloride thorium salts are commonly employed. Berzehus first prepared thorium by heating tetrachloride, ThCh, with potassium. Magnesium and calcium are the most common reductant. These metals are added to thorium halides in excess to ensure complete reduction. Excess magnesium or calcium is removed by heating at elevated temperatures in vacuum. One such thermal reduction of hahdes produces thorium sponge, which can be converted into the massive metal by melting in an electron beam or arc furnace. 

Titanium metal also can be produced by electrolytic methods. In electrolysis, fused mixtures of titanium tetrachloride or lower chlorides with alkaline earth metal chlorides are electrolyzed to produce metal. Also, pure titanium can be prepared from electrolysis of titanium dioxide in a fused bath of calcium-, magnesium- or alkali metal fluorides. Other alkali or alkaline metal salts can be substituted for halides in these fused baths. Other titanium com-pouds that have been employed successfully in electrolytic titanium production include sodium fluotitanate and potassium fluotitanate. 

The alkaline earths, particularly the lighter ones, have more definite water coordination, and a probable coordination number of 4. The heats of sublimation (Table I) of the magnesium salts are about 50 kcal/mole or higher, those for the calcium halides are over 60 kcal/mole, and for the heavier alkaline earths they run over 70 kcal/mole. For the beryllium halides other than the fluoride, however, the values are 30 to 33 kcal/mole. In... 

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