On the Crystal Structure of Some Basic Aluminium Salts.

Johansson, Georg; Gullman, Lars-Otto; Kjekshus, Arne; Söderquist, Rune

doi:10.3891/acta.chem.scand.14-0771

Cited by 366 publications

(235 citation statements)

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“…In the present experiments, a 5/6 basic aluminum chloride (ACH) salt marketed by Reheis Chemical Company under the tradename of Chlorhydrol | was used (see Table 2). The structure of this salt has not been completely determined, however, Johansson (1960) proposed that [AIt304(OH)24(H20)12] +7 is present, a cation that consists of a four-coordinated aluminum ion surrounded by 12 A104-0ctahedra joined together by common edges.…”

Section: Interlayering Cationmentioning

confidence: 99%

Physicochemical Properties of Montmorillonite Interlayered with Cationic Oxyaluminum Pillars

Occelli¹,

Tindwa

1983

Clays and clay miner.

228

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Abstract--By ion exchanging expandable clay minerals with large, cationic oxyaluminum polymers, "pillars" were introduced that permanently prop open the clay layers. On the basis of thermal, infrared spectroscopic, adsorption, and X-ray powder diffraction (XRD) analysis, the interlayering of commercial sodium bentonite with aluminum chlorohydroxide, lAI1304(OH)24(HzO)12] +7, polymers appears to have produced an expanded clay with a surface area of 200-300 m2/g. The pillared product contained both Br6nsted and Lewis acid sites. XRD and differential scanning calorimetry measurements indicated that the micropore structure of this interlayered clay is stable to 540~ Between 540 ~ and 760~ the pillared day collapsed with a corresponding decrease in surface area (to 55 m2/g) and catalytic cracking activity for a Kuwait gas oil having a 260~176 boiling range.

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Section: Interlayering Cationmentioning

confidence: 99%

Physicochemical Properties of Montmorillonite Interlayered with Cationic Oxyaluminum Pillars

Occelli¹,

Tindwa

1983

Clays and clay miner.

228

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“…Because high-purity crystals form when sulfate or selenate anions are added to cluster-containing solutions, the sulfate and selenate Al 13 Keggins have been widely studied, beginning with Johansson's work decades ago (11). In addition, these salts can be back-extracted into an aqueous solution in the presence of aqueous BaCl 2 to release the ions MO 4 Al 12 ðOHÞ 24 ðH 2 OÞ 12 7þ∕8þ ðaqÞ, [M ¼ AlðIIIÞ, Ga(III), and Ge(IV)] (12), thus affording a wider range of experimental studies to be conducted on both the solid and solution phases.…”

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confidence: 99%

Energetics of Al ₁₃ Keggin cluster compounds

Armstrong

Casey

Navrotsky

2011

Proc. Natl. Acad. Sci. U.S.A.

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The ϵ-Al 13 Keggin aluminum hydroxide clusters are essential models in establishing molecular pathways for geochemical reactions. Enthalpies of formation are reported for two salts of aluminum centered ϵ-Keggin clusters, Al 13 The formation of both ε-Al 13 Keggin cluster compounds is exothermic from oxide-based components but energetically unfavorable with respect to a gibbsite-based assemblage. To understand the relative affinity of the ϵ-Keggin clusters for selenate and sulfate, the enthalpy associated with two S-Se exchange reactions was calculated. In the solid state, selenium is favored in the Al 13 compound relative to the binary chalcogenate, while in 5 N HCl, sulfur is energetically favored in the cluster compound compared to the aqueous solution. This contribution represents the first thermodynamic study of ε-Al 13 cluster compounds and establishes a method for other such molecules, including the substituted versions that have been created for kinetic studies. Underscoring the importance of ε-Al 13 clusters in natural and anthropogenic systems, these data provide conclusive thermodynamic evidence that the Al 13 Keggin cluster is a crucial intermediate species in the formation pathway from aqueous aluminum monomers to aluminum hydroxide precipitates.aluminum hydrolysis | polyoxocations F ew subjects are more central to geochemistry and materials science than aluminum hydrolysis chemistry. From a geochemist's perspective, aluminum hydrolysis products are key to mineral paragenesis and watershed chemistry. In addition, nanometer-size aluminum hydroxide molecules, including Al 13 ϵ-Keggin clusters, are critical to both experiment and simulation to detail possible reaction pathways at the solid-water interface (1). Aluminum clusters form complexes with a variety of reactive components including clay particles, natural organic matter, viruses, bacteria, and spores and thus are of interest to the environmental community for applications in water treatment and contaminant remediation technologies (2). Such clusters have also been used in a wide variety of industrial and consumer applications (3) and, because of their unique size and reactivity, they are effective as clay pillars (4) and catalysts (5).At near-neutral and higher pH, the dominant multimeric aluminum complex in aqueous systems is the large polycation, ½Al 12 ðAlO 4 ÞðOHÞ 24 ðH 2 OÞ 12 7þ , which forms quickly via Al 3þ hydrolysis and is a precursor to solid flocs (6). It consists of a central tetrahedrally coordinated AlO 4 moiety, enveloped by a sheath of 12 edge-shared AlO 6 units in four sets of three linked trimers. The most familiar form of this molecule, referred to as ε-Al 13 , has a structure identical to the ϵ-isomer of the BakerFiggis-Keggin structures (7-9). This isomer has edge-shared trimeric capping groups organized around a central tetrahedral AlO 4 site that is inert. Under favorable conditions, other isomers and larger clusters can be synthesized by hydrothermal reaction or by slow aging at room temperature (10).Because high-purit...

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“…The most commonly used pillaring agent is the Keggin-like A113 oligomer [A~~~~,(~H)~,+,(H~O)~~.~]~-~)+ , made from twelve octahedra surronding a central aluminum tetrahedron (1,2).…”

Section: Introductionmentioning

confidence: 99%