Structure of acidic haloaluminate melts: Neutron diffraction and quantum chemical calculations

Journal Article · Sat Aug 15 00:00:00 EDT 1992 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.463063· OSTI ID:7294096

Blander, M; Bierwagen, E; Calkins, K G; Curtiss, L A; Price, D L; Saboungi, M ^[1]

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1. Argonne National Laboratory, Argonne, Illinois 60439 (United States)

The structure of molten mixtures of (KX){sub {ital y}}(AlX{sub 3}){sub 1{minus}{ital y}} was investigated by neutron diffraction for X=Cl and Br and {ital y}=0.25 and 0.33. These melts, known as acidic haloaluminates, contain different ionic species such as AlX{sup {minus}}{sub 4},Al{sub 2}X{sup {minus}}{sub 7}, Al{sub 3}X{sup {minus}}{sub 10}. The diffraction patterns were similar, although not identical, for the same halide pairs and showed features indicative of short-range and intermediate-range order. Quantum chemical calculations were carried out on AlX{sup {minus}}{sub 4}, Al{sub 2}X{sup {minus}}{sub 7}, and Al{sub 3}X{sup {minus}}{sub 10} to provide information needed to interpret the structural results within the framework of the random packing of structural units model. It is shown that the bent Al--X--Al bridge for Al{sub 2}X{sup {minus}}{sub 7}, obtained from the quantum chemical calculations, is necessary to represent well the structure, and that the values of the bond angles at the central halide atoms are around 110{degree}. Aluminum atoms are found to be tetrahedrally coordinated by the halide atoms, and information on the orientational correlations of neighboring Al{sub 2}X{sup {minus}}{sub 7} is derived.

• DOE Contract Number: W-31-109-ENG-38
• OSTI ID: 7294096
• Journal Information: Journal of Chemical Physics; (United States), Vol. 97:4; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM BROMIDES
NEUTRON DIFFRACTION
ALUMINIUM CHLORIDES
POTASSIUM COMPOUNDS
CHARGE STATES
CHEMICAL BONDS
CHEMICAL COMPOSITION
COORDINATION NUMBER
ELECTROLYTES
MIXTURES
MOLTEN SALTS
ORDER PARAMETERS
STRUCTURAL MODELS
ALKALI METAL COMPOUNDS
ALUMINIUM COMPOUNDS
BROMIDES
BROMINE COMPOUNDS
CHLORIDES
CHLORINE COMPOUNDS
COHERENT SCATTERING
DIFFRACTION
DISPERSIONS
HALIDES
HALOGEN COMPOUNDS
SALTS
SCATTERING
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies