Potassium with metal chlorides

Such alkali metal intercalates are extremely reactive, igniting in air and exploding on contact with water. Potassium can be replaced by a rf-block metal by reaction of KC with metal chloride, but the choice of solvent for the reactions is critical, as is the nature of the rf-block metal salt (e.g. CuCl2-2H20,... 

Mixed alkoxides of sodium and potassium can be used to prepare other bimetallic alkoxides hy transmetallation with metal chlorides. In particular, M[Al(OR)4] (Equation (16), M = In,i ... 

It is recovered commercially from monazite sand, which contains about 3%, and from bastnasite, which contains about 0.2%. Wohler obtained the impure element in 1828 by reduction of the anhydrous chloride with potassium. The metal is now produced commercially by reduction of the fluoride with calcium metal. It can also be prepared by other techniques. 

The monofluorophosphates can be prepared by neutralization of monofluorophosphoric acid (1). Sodium monofluorophosphate [7631 -97-2] is prepared commercially (57) by fusion of sodium fluoride and sodium metaphosphate, and the potassium monofluorophosphate [14104-28-0] can be prepared similarly. Insoluble monofluorophosphates can be readily prepared from reaction of nitrate or chloride solutions with sodium monofluorophosphate. Some salts are prepared by metathetical reactions between silver monofluorophosphate [66904-72-1] and metal chlorides. 

The potassium salts are the most soluble and other salts usually are precipitated by addition of the appropriate metal chloride to a solution of the corresponding potassium salt. The metaniobates, MNbO, and orthoniobates, MNbO, generally are prepared by fusion of the anhydrous mixed oxides. The metaniobates crystallize with the perovskite stmeture and are ferroelectric (131) (see Ferroelectrics). The orthoniobates are narrow band-gap semiconductors (qv) (132). 

The main metals in brines throughout the world are sodium, magnesium, calcium, and potassium. Other metals, such as lithium and boron, are found in lesser amounts. The main nonmetals ate chloride, sulfate, and carbonate, with nitrate occurring in a few isolated areas. A significant fraction of sodium nitrate and potassium nitrate comes from these isolated deposits. Other nonmetals produced from brine ate bromine and iodine. 

Reaction with hydrogen at 220°C in the presence of reduced nickel catalyst results in total decomposition to hydrogen chloride and carbon. An explosive reaction occurs with butylUthium in petroleum ether solution (4). Tetrachloroethylene also reacts explosively with metallic potassium at its melting point, however it does not react with sodium (5). 

Chloride salts (sodium chloride, potassium chloride) tend to interfere with the formation of a protective layer over metals. Chloride salts destroy the passivity of some stainless steels and cause them to fail by rapid cracking under tensile stress at temperatures higher than about 176°F (80°C). This type of failure is called chloride stress cracking (CSC) [186,194]. 

Apart from the fluoride, mercuric halides react explosively with potassium like all analogues of the other metals already mentioned. With mercurous salts, the reaction seems less violent since with mercurous chloride, molten potassium causes the mixture to incandesce without ever combusting. It is likely that other metals react too an extreme violent reaction was mentioned between indium and mercuric bromide. 

The quality of the refined metal, and the current efficiency strongly depend on the soluble vanadium in the bath and the quality of the anode feed. As the amount of vanadium in the anode decreases, the current efficiency and the purity of the refined product also decrease. A laboratory preparation of the metal with a purity of better than 99.5%, containing low levels of nitrogen (30-50 ppm) and of oxygen (400-1000 ppm) has been possible. The purity obtainable with potassium chloride-lithium chloride-vanadium dichloride and with sodium chloride-calcium chloride-vanadium dichloride mixtures is better than that obtainable with other molten salt mixtures. The major impurities are iron and chromium. Aluminum also gets dissolved in the melt due to chemical and electrochemical reactions but its concentrations in the electrolyte and in the final product have been found to be quite low. The average current efficiency of the process is about 70%, with a metal recovery of 80 to 85%. 

Diselenium dichloride and seleninyl chloride both explode on addition of potassium [1,3], while the metal ignites in contact with phosphorus trichloride vapour or liquid [2], Mixtures of potassium with sulfur dichloride or sulfur dibromide, phosphorus tribromide or phosphorus trichloride, and with phosgene are shock-sensitive, usually exploding violently on impact. Potassium also explodes violently on heating with disulfur dichloride, and with sulfur dichloride or seleninyl bromide without heating [3]. 

Several recent determinations of the alkali and alkaline earth metals in serum or urine have been reported. Barrett 29) determined potassium, sodium, and calcium in semm by diluting the samples with lanthanum chloride solution. Suttle and Field 3°) used atomic absorption spectroscopy to determine potassium and magnesium in sheep plasma. 

The outer tube has a porous fiber tip, which acts as the salt bridge to the analyte solution and the other half-cell. A saturated solution of potassium chloride is in the outer tube. The saturation is evidenced by the fact that there is some undissolved KC1 present. Within the inner tube is mercury metal and a paste-like material known as calomel. Calomel is made by thoroughly mixing mercury metal (Hg) with mercurous chloride (Hg2Cl2), a white solid. When in use, the following half-cell reaction occurs ... 

Binary Compounds. The thermodynamics of the formation of HfCl2, of HfCl4, fused sodium and potassium chlorides have been described. The reduction of ZrXj (X = Cl, Br, or I) with metallic Zr or A1 in molten AICI3 has been studied at temperatures from 250 to 360 °C, depending on the halide. The electronic spectra of the initial reaction products were consistent with either a solvated Zr complex or an intervalence Zr "-Zr" species. Further reduction resulted in the precipitation of reduction products which were identified by analysis and i.r., electronic, and X-ray powder diffraction spectra. The stability of the trihalides with respect to disproportionation was observed to increase from chloride to iodide thus ZrC and ZrCl2,0.4AlCl3 were precipitated, whereas only Zrlj was formed. ... 

Mercury is most accurately determined by the cold vapor atomic absorption spectroscopic method. The instrument is set at the wavelength 253.7 nm. The metal, its salts and organic derivatives in aqueous solution can be measured by this method. The solution or the solid compounds are digested with nitric acid to convert into water-soluble mercury(ll) nitrate, followed by treatment with potassium permanganate and potassium persulfate under careful heating. The excess oxidants in the solution are reduced with NaCl-hydroxylamine sulfate. The solution is treated with stannous chloride and aerated. The cold Hg vapor volatdizes into the absorption cell where absorbance is measured. 

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