Chlorides alkaline earth

The reaction of chlorine gas with a mixture of ore and carbon at 500—1000°C yields volatile chlorides of niobium and other metals. These can be separated by fractional condensation (21—23). This method, used on columbites, is less suited to the chlorination of pyrochlore because of the formation of nonvolatile alkaU and alkaline-earth chlorides which remain in the reaction 2one as a residue. The chlorination of ferroniobium, however, is used commercially. The product mixture of niobium pentachloride, iron chlorides, and chlorides of other impurities is passed through a heated column of sodium chloride pellets at 400°C to remove iron and aluminum by formation of a low melting eutectic compound which drains from the bottom of the column. The niobium pentachloride passes through the column and is selectively condensed the more volatile chlorides pass through the condenser in the off-gas. The niobium pentachloride then can be processed further. 

A composition for dissolving filter-cake deposits left by drilling mud in wellbores is composed of an aqueous solution of citric acid and potassium chloride, alkali metal formate, acid tetraphosphate, alkaline earth chloride, and alkali metal thiophosphate [1012]. 

Figure 2 shows the osmotic coefficient as a function of the molality for the alkaline earth chlorides (Goldberg and Nuttall,... 

Figure 2. Osmotic coefficient of aqueous alkaline earth chlorides as a function of...

Table 4.2. Single ion activity coefficients (molal scale) for alkaline earth chlorides at 25 °C derived from hydration theory [11].

Kautz CF, Robinson AL. The hydrolysis of sucrose by hydrochloric acid in the presence of alkali and alkaline earth chlorides. JACS 1928 50(4) 1022-1030. 

The presence of alkali and alkaline earth chlorides may also hinder precipitation of the sulphide thus, from a 0001 molar solution of lead chloride in water at 20° C., precipitation is completely inhibited by hydrogen chloride alone if in a concentration of 1-riV, and by decreasing concentrations of the acid in the presence of increasing quantities of calcium, ammonium or potassium chloride. Cadmium sulphide, precipitated from hydrochloric acid solution, contains adsorbed chlorine,1 the amount depending on the conditions of the precipitation the precipitation is incomplete at 80° C. 

Alkaline Earths Chlorides. lit) ee.. of the 1 20 aqueous solid ion should he nlTcofcd neither by ammonium oxalate Solid inn nor hy silver nitride solution. 

By the action of alkaline earth chlorides on the sodium and potassium salts, the following have been obtained ... 

CALCIUM CHLORIDE. Calcium chloride. [CAS I004.7-52-4J. CaClj, is a white, crystalline salt that is very soluble in water. Solutions containing 30-45 wl % CaCh are used commercially. Of the alkaline-earth chlorides it is the most soluble in water, h is extremely hygroscopic and liberates large amounts of heat during water absorption and on dissolution. It forms a series of hydrates containing one. two, four, and six moles of water per mole of caJcium chloride (Table I). Another hydrate. CaCl 0.331 I O. has been identified, mol wi 116.98 94.8 wl % CaCl, heat of solution in water to infinite dilution. -71.37 kJ/mol (- 17.06 keal/mol). 

When 8.900 g of a mixture of an alkali metal chloride (XC1) and an alkaline earth chloride (YCI2) was dissolved in 150.0 g of water, the freezing point of the resultant solution was —4.42°C. Addition of an excess of aqueous AgNC>3 to the solution yielded a white precipitate with a mass of 27.575 g. How much of each metal chloride was present in the original mixture, and what are the identities of the two metals X and Y ... 

E. P. Alvarez 2 found that the pemitrates react with soln. of lead acetate (white precipitate), silver nitrate (white precipitate), mercurous nitrate (white precipitate with rapid decomposition), mercuric chloride (red precipitate), copper sulphate (blue precipitate), zinc and cadmium sulphates (white precipitate), bismuth nitrate (white precipitate), gold chloride (slight effervescence and escape of oxygen), manganous chloride (pink precipitate), nickelous chloride or sulphate (greenish-white precipitate), cobaltous nitrate and chloride (pink precipitate), ferrous sulphate (green or bluish-green precipitate), ferric chloride (red ferric hydroxide), and alkaline earth chlorides (white precipitates). The precipitates are all per-salts of the bases in question. 

The measured ionization potentials of the MCI species in the alkaline earth chlorides are approximately 0.2 eY lower than those of the corresponding metals (38, 39). Thus one estimates the IP [EuCl(g) ] as 5.4 eV. Combination of this value with the appearance potential, 10.3 eV of EuC1+/EuC12 (20) gives the bond dissociation energy Dq (ClEu-Cl) according to Eq. (7)... 

Hydrochloric acid has also been used for the acidification.90 In this case the aconitic acid is then crystallized from the solution of aconitic acid and alkaline earth chlorides. 

Halides Halogens, hydrogen halides, SOCl2, CCLt Fused silica, glass, metals, alumina, alkaline chlorides, alkaline earth chlorides... 

Figure 6 Specific conductance K vs. ionic radii [52] for molten alkali chlorides MCI (M = Li, Na, K, Rb, Cs) at 1080 K and for molten alkaline earth chlorides MC12 (M = Be, Mg, Ca, Sr, Ba) at 1200 K.

The three alkaline earth metals decompose water at different rates, forming hydroxides and hydrogen gas. Their hydroxides are strong bases, although with different solubilities barium hydroxide is the most soluble, while calcium hydroxide is the least soluble among them. Alkaline earth chlorides and nitrates are very soluble the carbonates, sulphates, phosphates, and oxalates are insoluble. The sulphides can be prepared only in the dry they all hydrolyse in water, forming hydrogen sulphides and hydroxides, e.g. 

Previously, this was done with pyrolusite, but modem processes use arsenic acid (with 2-aminoanthraquinone) and sodium m-nitrobenzenesulfonate (with 1-amino-anthraquinone). The sulfite can ako be removed by precipitation with alkaline earth chlorides, e.g., barium chloride. The procedure given above has the advantage that it yields a product which is practically ash-free. The ammonium chloride is added to neutralize the alkali formed in the reaction (the arsenite forrned acts as free sodium hydroxide). The mother liquors, which contain arsenious acid, are poisonous, of course, and must be handled carefully. They are usually treated with milk ef lime to render them harmless. The toxicity of such waste products is frequently ovo emphasized if they are discharged into large streams, for example, ftey rarely poison the fish. In plant operations, the excess anunonia is collected and used over without further treataent For a general discussion of the sulfonation of anthraquinone, see page 56 ff. 

Ans. Choose 34 or more soluble, ionic chlorides—the other alkali metal chlorides (4), the alkaline earth chlorides... 

Alkaline Earths Chlorides. liO cc. of the 1 20 iwineoiiH sohilhiii should 1k iilTcctcd iiinthcr hy ainnionium o.xalato... 

In 1961 Hayes and Twidell (8) found that if calcium fluoride crystals containing trivalent thulium were irradiated with x-rays, some of the thulium was converted to the divalent state. This discovery was the first of many in the study of dilute solutions of divalent rare earth ions. Most workers prefer to study the alkaline earth fluorides since these materials are stable with respect to air and have more attractive mechanical properties than the alkaline earth chlorides, bromides, and iodides. Enough work has been carried out in these softer materials to show that reactions similar to those in the fluorides do occur. 

D. L. Hildenbrand, "Dissociation Energies and Chemical Bonding in the Alkaline-Earth Chlorides from Mass Spectrometric Studies," J. Chem. Phys., 52, 5751 (1970). 

The crude magnesium obtained from electrolysis or thermal reduction has to be purified (refined) before further processing. This is carried out by mixing salt melts (alkali and alkaline earth chlorides or fluorides) with the liquid metal. The purest magnesium is manufactured by distillation. 

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