The oxide hydroxides

The building unit common to all five oxide hydroxides (a P y 5 high pressure) is the Fe03(0H)3 octahedron, spatially arranged in five different ways. 

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Mir-slaked lime contains various proportions of the oxides, hydroxides, and carbonates of calcium and magnesium which result from excessive exposure of quicklime to air that vitiates its quaUty. It is partially or largely decomposed quicklime that has become hydrated and carbonated. 

The CAS registry Hsts 5,037 aluminum-containing compounds exclusive of alloys and intermetaUics. Some of these are Hsted in Table 1. Except for nepheline and alunite in the USSR and Poland, bauxite is the raw material for all manufactured aluminum compounds. The term bauxite is used for ores that contain economically recoverable quantities of the aluminum hydroxide mineral gibbsite or the oxide—hydroxide forms boehmite and diaspore. 

Early examples of such branched polysulphides, e.g. Thiokol FA, are believed to possess hydroxyl end groups and are coupled by means of zinc compounds such as the oxide, hydroxide, borate and stearate by a mechanism which is not understood. Later elastomers, e.g. Thiokol ST, have been modified by a restricted reductive cleavage (see below) and this generates thiol (mercaptan) end groups. These may be vulcanised by oxidative coupling as illustrated below with lead peroxide ... 

According to the depth profile of lithium passivated in LiAsF6 / dimethoxyethane (DME), the SEI has a bilayer structure containing lithium methoxide, LiOH, Li20, and LiF [21]. The oxide-hydroxide layer is close to the lithium surface and there are solvent-reduction species in the outer part of the film. The thickness of the surface film formed on lithium freshly immersed in LiAsF /DME solutions is of the order of 100 A. 

There is a complex relationship among the oxide, hydroxide, and hydrous oxide of aluminum. Conversion between several phases is possible as a result of the reactions... 

The monoxides and dioxides of germanium, tin, and lead are all known. Especially when obtained as precipitates, the oxides contain water and consist of a mixture of the oxide, hydroxide, and hydrous oxide. For example, GeO, GeO-xl l20, and Ge(OH)2 (which could be written as GeOH20) all exist in equilibria or in mixtures. GeO is obtained from the reaction... 

The BET method requires that the sample be dried and outgassed to remove adsorbed water. This procedure may, if the outgassing temperature is too high, lead to a phase change at the surface of the oxide hydroxide and hence, an alteration in the specific surface area of the sample. Clausen and Eabricius (2000) recommend that ferrihydrite be outgassed at room temperature, at which temperature, a stable BET surface area is obtained after 19 hr of outgassing. 

Many compounds of curium are known. They include the oxides, Cm02 and Cm203, fluorides CmF4 and CmFs, other halides, CmXa hydroxide, Cm(OH)3, and oxalate Cm2(C204)3. The oxide, hydroxide, fluoride, and oxalate salts are insoluble in water and may be obtained by precipitation reactions. 

The heptahydrate is formed by dissolving the oxide, hydroxide or carbonate in hydrochloric acid, followed by crystaUization. The anhydrous chloride is obtained by heating oxide, hydroxide, or carbonate in an atmosphere of dry hydrogen chloride. 

In aqueous media lutetium occurs as tripositive Lu3+ ion. All its compounds are in +3 valence state. Aqueous solutions of all its salts are colorless, while in dry form they are white crystalline solids. The soluble salts such as chloride, bromide, iodide, nitrate, sulfate and acetate form hydrates upon crystallization. The oxide, hydroxide, fluoride, carbonate, phosphate, and oxalate of the metal are insoluble in water. The metal dissolves in acids forming the corresponding salts upon evaporation of the solution and crystallization. 

The second method, illustrated in Section B for the ammonium salt, relies on the direct stoichiometric acid-base reaction between V2Os and the oxide, hydroxide, carbonate, or hydrogen carbonate (bicarbonate) of the desired positive ion. Surprisingly, this method works well for quite a variety of ions, even in cases where both reactants are only slightly soluble in water (e.g., CaO + V2Os). 

This process leads to the precipitation of the oxides, hydroxides or carboxylates if we replace OH" by L" in the last reaction. If this polycondensation can be stopped or if it is slow enough, a colloidal solution is obtained that has rheological properties useful for application purposes. 

Table 2.3 lists ternaries that have been deposited, together with indication of when clear single compounds formation was verified. While solid solution formation is usually the goal of these smdies, it should be kept in mind that separate phases, either as a composite or as separate layers, may be required for some purposes. For example, bilayers of CdS/ZnO and CdS/ZnS have been deposited from single solutions. These depositions depend on the preferential deposition of CdS over ZnS and, in the case of the former, the often-encountered greater ease of formation of the oxide (hydroxide) than the sulphide of Zn. 

The alkali niobates are most conveniently prepared by the action of caustic alkalis on niobic acid or on solutions of niobium oxytri-fluoride. Other compounds of niobic acid and bases are generally prepared by fusing niobic add with the oxide, hydroxide, carbonate, or other salt of the metal. Occasionally double decomposition of a soluble alkali niobate and a soluble salt of the metal has been employed. Larsson s method1 consists in predpitating a solution of potassium niobate with a salt of a metal the dried predpitate is fused for thirty-six hours at a high temperature with boric acid, and the melt is boiled with water to which hydrochloric acid has been added. The residue consists of crystals of the insoluble niobate of the metal, usually the metaniobate. 

Sr(N3)j is not discussed by Sax (Ref 24) but its effects should be considered similar to those of the alkali and alkaline earth azides Sr azide was first prepd in 1898 by Dennis Benedict (Ref 1) and in the same year by Curtius Rissom (Ref 2) by the action of HNj on the oxide, hydroxide or carbonate of Sr. Its prepn has also been described by Mellor (Ref 7), Gmelin (Ref 9), Audrieth (Ref 10) and others (Refs 11, 15, 18, 19 25). The cryst structure of Sr(N3)2 was investigated to a limited extent by A.C.Gill (cited in Ref 1) and in detail by Llewellyn Whitmore (Ref 15) who established its orthorhmb nature as ionic, with a linear sym azide ion, N N 1.12A, and Sr to N distance of 2.63 to 27lX. Kahovec Kohlrausch (Ref 16) detd, from the Raman Effect, both on cryst powd and in soln, frequencies which corresponded to sym. oscillation in a linear triatomic molecule. 

For the group 6 and 7 elements, also the oxide/hydroxide molecules have been synthesized. For elements of group 8, the tetroxide is the species of choice, since this molecule is very volatile. For future studies with the p-elements around atomic number 114 the elements are expected to be volatile in their atomic state and should behave like noble metals or even like a noble gas. 

Oxides and oxide hydroxides of Tc and Re are typically formed in an O2/H2O containing gas phase. They were extensively studied, mostly using the method of thermochromatography [56-67]. The technique has also been applied to develop Tc and Re generator systems for nuclear medical applications [68,69]. In their works, M. Schadel et al. [70] and R. Eichler et al. [53] studied the oxide and the oxide hydroxide chemistry of trace amounts of Re in an 02/H20-containing system with respect to its suitability for a first gas chemical identification of Bh. They investigated the behavior... 

Corrosion products such as the oxides, hydroxides, carbonates, sulfates, basic sulfates hydroxy carbonates, hydroxy chlorides are formed in the various environments (marine, urban, rural, industrial) and the initially loosely bound products may become adherent in the course of time. Corrosion can occur in the pores of the corrosion product layers. The low corrosion rate observed in atmospheric corrosion, R has been expressed as ... 

The tetrahalides of the Group IVA elements hydrolyze to give the oxides, hydroxides, or hydrous oxides (E02, E(OH)4, or E02 2H20). Typical processes of this type are represented by the equations... 

Hydrous Oxides. This term is generally taken to include the oxides, hydroxides, and oxyhydroxides of aluminium, iron and manganese, which form in soil when these elements are released from primary minerals by weathering. They exist mainly as small particles in the claysized fraction of a soil (<2 pm), and also as coatings on other soil minerals or as components of larger aggregates. 

The oxides, hydroxides, and mixed oxyhydroxides of aluminum form an extended family of compounds that have immense technological importance. 

Inter-conversions between the compounds listed in Table 1-1 are possible and often occur readily. The oxide hydroxides dehydrate to their anhydrous structural counterparts and ultimately to hematite on heating. At lower temperatures and in solution, inter-conversions usually require dissolution followed by reprecipitation of the new phase. Oxidation or reduction reactions are also possible. An overview of the more frequent inter-conversions is presented in Fig. 1-2. 

The reaction vessels in which the iron oxides have been prepared are usually stained with the product. The oxide hydroxides and hematite may be removed by overnight treatment (25 °C) with 4 M HCl (or in difficult... 

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