Alkali and alkaline earth metals carbonates

Alkali and alkaline earth metals, Carbon dioxide, carbon tetrachloride, or other chlorinated... 

The alkylation reaction of various alkali and alkaline-earth metal carbonates with alkyl halides R(CH2)nX (X = Cl, Br, I) is a primary synthetic procedure in organic chemistry for obtaining various symmetrical and unsymmetrical dialkyl carbonates under phase-transfer conditions in polar aprotic solvents [45]. Excellent yields may be obtained by running the reaction at 383 K in ionic liquids such as... 

Alkali and alkaline earth metals, Carbon dioxide, carbon tetrachloride, and other chlorinated hydrocarbons. (Also prohibit eg. sodium, magnesium, calcium, potassium, water, foam and dry chemical on fires involving these metals—dry sand should powdered aluminum. be available). 

Although the ion pairs of a-substituted benzyl anions and the corresponding cations are chiral species, which, in addition, often bear a pyramidal and hence stereogenic carbon atom, in most cases rapid racemization of the alkali and alkaline earth metal derivatives occurs in solution... 

Salt-inclusion solids described herein were synthesized at high temperature (>500°C) in the presence of reactive alkali and alkaline-earth metal halide salt media. For single crystal growth, an extra amount of molten salt is used, typically 3 5 times by weight of oxides. The reaction mixtures were placed in a carbon-coated silica ampoule, which was then sealed under vacuum. The reaction temperature was typically set at 100-150 °C above the melting point of employed salt. As shown in the schematic drawing in Fig. 16.2, the corresponding metal oxides were first dissolved conceivably via decomposition because of cor-... 

With less polar solvents and more basic allyl anions the compounds are present as ion pairs. The carbon-metal bond with the alkali and alkaline earth metals are known to have high ionic character. The allyl compounds behave accordingly as salts. The structures of allyl compounds of the alkali and alkaline earth metals are of two fundamental types, a 41 (or metal cation is associated closely with a single terminal allylic carbon, and the rf 1 (or ji) type, 15, in which the cation bridges the two terminal allylic positions. 

Intimate mixtures of chlorates, bromates or iodates of barium, cadmium, calcium, magnesium, potassium, sodium or zinc, with finely divided aluminium, arsenic, copper carbon, phosphorus, sulfur hydrides of alkali- and alkaline earth-metals sulfides of antimony, arsenic, copper or tin metal cyanides, thiocyanates or impure manganese dioxide may react violently or explosively, either spontaneously (especially in presence of moisture) or on initiation by heat, friction, impact, sparks or addition of sulfuric acid [1], Mixtures of sodium or potassium chlorate with sulfur or phosphorus are rated as being exceptionally dangerous on frictional initiation. 

PTFE, FEP and PFA are attacked only by alkaline metals and their organic derivatives elemental fluorine and chlorine trifluoride alkali and alkaline earth metals with their oxides and carbonates above 350°C. The other halogens, aqua regia, nitrosulfuric acid mixtures, oleum (fuming sulfuric acid) and solvents are without significant effects. 

Magnesium carbonate forms several double salts with salts of alkali and alkaline earth metals and ammonium ion. Some examples are ... 

Bimetallic Ni-based catalysts were also studied for SR of higher hydrocarbons in order to avoid the carbon formation and sulfur poisoning problems of conventional Ni catalysts.Murata et prepared a series of bimetallic catalysts by adding alkali and alkaline-earth metals to Ni catalyst supported on zirconia and alumina for SR of i-Cg and methylcyclohexane (MCFI). The performance of various bimetallic catalysts for SR of i-Cg and MCH are summarized in Figures 21a and 21b, respectively. It was reported that the stability of Ni/Zr02 is considerably improved by the addition of alkaline-earth metals (M), particularly strontium, to the catalyst with an M/Ni ratio of 0.5 by... 

Sulphur is soluble in solutions of the sulphides of the alkali metals, including ammonium, with the formation of yellow solutions of polysulphides.6 The alkali carbonates and the hydroxides of the alkali and alkaline earth metals, in aqueous solution, also dissolve sulphur, producing sulphides or polysulphidcs together with thiosulphates and sulphites. In all probability the ideal equation for hydroxides is ... 

The thiocarbonates of the alkali and alkaline earth metals are soluble in water. The alkali thiocarbonates are yellow in colour. In concentrated solution these salts are fairly stable, but in dilute solution they are gradually decomposed, forming the carbonate and hydrogen sulphide. 

The salts are usually prepared by the interaction of arsenious sulphide with the metallic sulphide, hydrosulphide or carbonate, taking care to exclude air to prevent the formation of thioarsenates. Thus, Nilson12 obtained the salts of the alkali and alkaline earth metals by dissolving arsenious sulphide in the aqueous solutions of the respective hydrosulphides and concentrating in vacuo. 

Many compounds involving the alkali and alkaline earth metals are used as desiccants, or chemicals that can remove water from a material. Lithium hydride, potassium carbonate, calcium... 

It should not be supposed that all metal derivatives of cyclopentadiehe are sandwichlike molecules. In many cases, the metal is joined to just one of the carbons in the ring through a single (cr) bond, which, however, often has considerable ionic character. Metal-to-earbon bonds almost certainly exist in the cyclopentadiene derivatives of the alkali and alkaline-earth metals, the rare earths, and certain of the post-transitioii elements. 

Soluble phosphates can be deposited from aqueous solutions, and this method may also yield snitable single crystals for structure determination and physical measmements. This method is commonly used to obtain hydrated and acid phosphates of soluble cations, for example, alkali and alkaline earth metals, NH4+. Acid phosphates snch as KDP (KH2PO4) may be prepared by partial nentralization of phosphoric acid with metal hydroxides or carbonates. 

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