Alkaline earth metals ionic hydroxides

Barium reacts with metal oxides and hydroxides in soil and is subsequently adsorbed onto soil particulates (Hem 1959 Rai et al. 1984). Adsorption onto metal oxides in soils and sediments probably acts as a control over the concentration of barium in natural waters (Bodek et al. 1988). Under typical environmental conditions, barium displaces other adsorbed alkaline earth metals from MnO2, SiO2, and TiO2 (Rai et al. 1984). However, barium is displaced from Al203 by other alkaline earth metals (Rai et al. 1984). The ionic radius of the barium ion in its typical valence state (Ba+) makes isomorphous substitution possible only with strontium and generally not with the other members of the alkaline earth elements (Kirkpatrick 1978). Among the other elements that occur with barium in nature, substitution is common only with potassium but not with the smaller ions of sodium, iron, manganese, aluminum, and silicon (Kirkpatrick 1978). 

As would be expected, the ionic oxides are formed by the alkali and alkaline earth metals, the most nearly covalent oxides by the nonmetais. The transition metals and many of the other heavy metals form oxides whose bonds are conveniently regarded as being intermediate between the extremes. Many of the oxides react with water to form hydroxides, often the acids and bases of the chemical laboratory. The ionic oxides yield... 

The most common soluble strong bases are the ionic hydroxides of the alkali metals, such as NaOH, KOH, and the ionic hydroxides heavier alkaline earth metals, such as Sr(OH)2. These compounds completely dissociate into ions in aqueous solution. Thus, a solution labeled 0.30 M NaOH consists of 0.30 MNa ([Pg.665]

Common strong bases are the ionic hydroxides of the alkali metals and the heavy alkaline earth metals. 

Inorganic hydroxides with the highest degree of ionicity are the binary hydroxides of the alkali and alkaline earth metals, Me OH and Me"(OH)2 with Me = Na, K. .., and Me" = Mg, Ca. .., respectively. They all contain well-defined, essentially non H-bonded OH anions. 

Values of the ionic standard partial molar volumes of the hydrogen, alkali metal, alkaline earth metal, and anunonium cations and hydroxide, hahde, nitrate, perchlorate, and sulfate anions from 0 to 200°C at 25°C intervals have been reported by Marcus in Refs. 79-81. Conventional values V " for these ions (except CIO ) and also for HCOj" and HS are reported by Tanger and Helgeson [84] from 0 to 350°C at 25°C intervals. 

Reactive electrodes refer mostly to metals from the alkaline (e.g., lithium, sodium) and the alkaline earth (e.g., calcium, magnesium) groups. These metals may react spontaneously with most of the nonaqueous polar solvents, salt anions containing elements in a high oxidation state (e.g., C104 , AsF6 , PF6 , SO CF ) and atmospheric components (02, C02, H20, N2). Note that ah the polar solvents have groups that may contain C—O, C—S, C—N, C—Cl, C—F, S—O, S—Cl, etc. These bonds can be attacked by active metals to form ionic species, and thus the electrode-solution reactions may produce reduction products that are more stable thermodynamically than the mother solution components. Consequently, active metals in nonaqueous systems are always covered by surface films [46], When introduced to the solutions, active metals are usually already covered by native films (formed by reactions with atmospheric species), and then these initial layers are substituted by surface species formed by the reduction of solution components [47], In most of these cases, the open circuit potentials of these metals reflect the potential of the M/MX/MZ+ half-cell, where MX refers to the metal salts/oxide/hydroxide/carbonates which comprise the surface films. The potential of this half-cell may be close to that of the M/Mz+ couple [48],... 

Discrete OH" ions exist only in the hydroxides of the more electropositive elements such as the alkali metals and alkaline earths. For such an ionic material, dissolution in water results in formation of aquated metal ions and aquated hydroxide ions ... 

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