II Salt Hydrates

Electrolytic chromium and 40 to 50 ml. of the appropriate acid (see Table I) are mixed in the test tube A (Fig. 3). The adapter B is immediately lowered into place and nitrogen 

The product and the filter stick (Fig. 4a), together with a number of 24/40 S.T. test tubes and deoxygenated solvents, are transferred into the nitrogen-filled glove box. The filter stick 

The crystal structure of CrCl2-4H20 shows the chromium(II) ion to be surrounded by a grossly distorted octahedron of four water and two chloride ligands. The single-crystaP and reflectance spectra of this complex have been measured, and the complex band system centered on 14,000 cm. has been interpreted on the basis of these distortions. Aqueous solution spectra between 8,000 and 20,000 cm. are identical for all 

Solutions of CrCl2 2CH3CN and the wet solid are extremely sensitive to oxygen. When dried, however, the complex remains unchanged in air for several minutes before oxidation becomes apparent. It is virtually insoluble in acetonitrile but quite soluble in ethanol. The room-temperature magnetic moment (4.8 B.M.) and electronic spectrum are consistent with a high-spin distorted octahedral Cr + ion.  

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It can also be precipitated in a hydrated form by the oxidation of a manganese(II) salt, by, for example, a peroxodisulphate ... 

Addition of an alkali metal hydroxide solution to an aqueous solution of a nickel(II) salt precipitates a finely-divided green powder. nickel(II) hydroxide NilOHfj on heating this gives the black oxide. NiO. which is also obtained by heating nickel(II) carbonate or the hydrated nitrate. Black nickel(II) sulphide, NiS, is obtained by passing hydrogen sulphide into a solution of a nickel(II) salt. 

Hydrated copper(ll) hydroxide, Cu(OH)2, is precipitated as a pale blue solid when alkali is added to an aqueous solution of a copper(II) salt ... 

Furthermore, it is the system. Hydrate I/Hydrate II (or Anhydrous Salt), that possesses a definite pressure at a particular temperature this is independent of the relative amounts, but is dependent upon the nature of the two components in equilibrium. It is incorrect, therefore, to speak of the vapour pressure of a salt hydrate. ... 

Wet preparation of red iron oxides can involve either a hydrothermal process (see Hydrothermal processing) or a direct precipitation and growth of iron oxide particles on specially prepared nucleating seeds of Fe202- In the hydrothermal process, iron(II) salt is chemically oxidized to iron(III) salt, which is further treated by alkahes to precipitate a hydrated iron(III) oxide gel. The gel can be dehydrated to anhydrous hematite under pressure at a temperature around 150°C. 

Ghromium(II) Compounds. The Cr(II) salts of nonoxidizing mineral acids are prepared by the dissolution of pure electrolytic chromium metal ia a deoxygenated solution of the acid. It is also possible to prepare the simple hydrated salts by reduction of oxygen-free, aqueous Cr(III) solutions using Zn or Zn amalgam, or electrolyticaHy (2,7,12). These methods yield a solution of the blue Cr(H2 0)g cation. The isolated salts are hydrates that are isomorphous with and compounds. Examples are chromous sulfate heptahydrate [7789-05-17, CrSO 7H20, chromous chloride hexahydrate... 

Eisenoxydul-hydrat, n. ferrous hydroxide, iron(ll) hydroxide, -oxyd, n. ferrosoferric oxide, iron(II,III) oxide, magnetic iron oxide (FeaOi). -salz, n. ferrous salt, iron(II) salt, -sulfat, n. ferrous sulfate, iron(II) sulfate, -verbindung, /. ferrous compound, iron(ll) compound. 

Kupferoxyd, n. cupric oxide, copper(II) oxide, -ammoniak, n. ammoniacal copper oxide, cu-prammonium. -ammoniakkunstseide, -am-moniakzellulose, /. cuprammonium rayon, -hydrat, n. cupric hydroxide, copper(II) hydroxide. -salz, n. cupric salt, copper(II) salt. 

Jfickeloxydul, n. nickelous oxide, nickel(II) oxide, NiO. -hydrat, n, nickelous hydroxide, nickel (II) hydroxide, -salz, n. nickelous salt, nickel(II) salt, -verbindung,/. nickelous compound, nickel(II) compound. Nickelpapier, n. nickel foil, nickelplattiert, a. nickel-plated. 

The standard redox potential is 1.14 volts the formal potential is 1.06 volts in 1M hydrochloric acid solution. The colour change, however, occurs at about 1.12 volts, because the colour of the reduced form (deep red) is so much more intense than that of the oxidised form (pale blue). The indicator is of great value in the titration of iron(II) salts and other substances with cerium(IV) sulphate solutions. It is prepared by dissolving 1,10-phenanthroline hydrate (relative molecular mass= 198.1) in the calculated quantity of 0.02M acid-free iron(II) sulphate, and is therefore l,10-phenanthroline-iron(II) complex sulphate (known as ferroin). One drop is usually sufficient in a titration this is equivalent to less than 0.01 mL of 0.05 M oxidising agent, and hence the indicator blank is negligible at this or higher concentrations. 

CN l-(N-methylglycine)-5-L-valine-8-L-alanineangiotensin II acetate (salt) hydrate saralasin... 

The reactions of acetylenes with thallium(III) salts are of considerable interest in that the results can be used in a qualitative comparison of reactivity between thallium(III) and mercury(II). Mercury(II) salt-catalyzed hydration of the C=C bond is a much studied and synthetically very useful process, although the detailed mechanism of the reaction is not known. The only published data available on the reactions of acetylenes with thallium-(III) salts are due to Uemura et al. 161), who employed thallium(III)... 

Hydration of unactivated alkynes is an important method for functionalizing this plentiful hydrocarbon source. Therefore, a variety of metal ions have been proposed as catalysts for this reaction, and almost all of the reported additions of water to terminal alkynes follow the Markonikov rule. The hydration of l-aUcynes with Hg(II) salts in sulfuric acid [85], RuCh/aq.HCl [86, 87], K[Ru (edta-H)Cl] 2H20 [88], RhCl,.3H20/aq. HCl [89], RhCl3/NR4 [90], Zeise-type Pt(II) complexes [91-93], and NaAuCl4 [94] produced exclusively methyl ketones (Eq. 6.46). 

Ethanesulfonic acid, 2-[(ethoxymethyl)[2-(l-hydroxyethyl)-6-methylphenyl] amino]-2-OXO-, sodium salt, hydrate (1 1), should be >95% pure (HEMA-producing sulfonic acid metabolite, referred to from this point as Metabolite II)... 

Crystallization yields the commercial product, pink heptahydrate. Further oxidation of this salt in dilute H2SO4 with ozone or fluorine produces hydrated cobalt(III) sulfate, 002(804)3 I8H2O. This blue octadecahydrate, 002(804)3 I8H2O also is obtained by electrolytic oxidation of cobalt(II) chloride or any cobalt(II) salt solution in 8M sulfuric acid. 

Nickel(II) salts, such as NiCl2, NiBr2 and Ni(acac)2, are commercially available in anhydrous form as inexpensive compounds (< 200-300/mol), and some others, such as Ni(0Ac)2-4H20 and Ni(N03)2-6H20, are also inexpensive but available only as hydrates. Recently, Ni(II) on C was prepared from Ni(N03)2-6H20 and charcoal and used as needed... 

Hydration and Hydroalkoxylation of Alkynes Gold compounds were first applied to catalyze these types of reactions by Utimoto et al. in 1991, when they studied the use of Au(III) catalysts for the effective activation of alkynes. Previously, these reactions were only catalyzed by palladium or platinum(II) salts or mercury(II) salts under strongly acidic conditions. Utimoto et al. reported the use of Na[AuCI41 in aqueous methanol for the hydration of alkynes to ketones [13]. 

Various methods to prepare tris(ar-diimine) complexes of many metals in low oxidation states have been devised, mainly by Herzog and co-workers.32 Those used for chromium complexes are illustrated in Schemes 5 and 6. Chromium(II) salts, anhydrous or hydrated, are the commonest starting materials. To these are added stoichiometric amounts of the diimine,... 

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