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Aluminium arsenate

Aluminium arsenate
Names
Other names
Aluminium arsenate
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/Al.AsH3O4/c;2-1(3,4)5/h;(H3,2,3,4,5)/q+3;/p-3
    Key: RCJAOTMBSRLOJZ-UHFFFAOYSA-K
  • (Octahydrate): InChI=1S/Al.AsH3O4.8H2O/c;2-1(3,4)5;;;;;;;;/h;(H3,2,3,4,5);8*1H2/q+3;;;;;;;;;/p-3
    Key: CHNKHEXWDMIYLG-UHFFFAOYSA-K
  • [O-][As](=O)([O-])[O-].[Al+3]
  • (Octahydrate): O.O.O.O.O.O.O.O.O=[As]([O-])([O-])[O-].[Al+3]
Properties
AlAsO4
Molar mass 165.899 g·mol−1
Appearance colourless crystals
Density 3.25 g/cm3
Melting point 1,000 °C (1,830 °F; 1,270 K)
insoluble
10−18.06 for 2 AlAsO4.7 H2O.[1]
1.596
Structure
hexagonal
Thermochemistry
145.6 J/mol K
-1431.1 kJ/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Aluminium arsenate is an inorganic compound with the formula AlAsO4.[2] It is most commonly found as an octahydrate. It is a colourless solid that is produced by the reaction between sodium arsenate and a soluble aluminium salt. Aluminium arsenate occurs naturally as the mineral mansfieldite.[3] Anhydrous form is known as an extremely rare, fumarolic mineral alarsite[4] A synthetic hydrate of aluminium arsenate is produced by hydrothermal method. with the formulation Al2O3·3As2O5·10H2O.[5]

Modification of aluminium orthoarsenate was carried out by heating different samples to different temperatures. Both amorphous and crystalline forms were obtained.[6] The solubility product was determined to be 10−18.06 for aluminium arsenate hydrate of formula AlAsO4·3.5H2O.[1] Like gallium arsenate and boron arsenate, it adopts the α-quartz-type structure. The high pressure form has a rutile-type structure in which aluminium and arsenic are six-coordinate.

References

  1. ^ a b Fernando L. Pantuzzo, Luciano R.G. Santos, Virginia S.T. Ciminelli "Solubility-product constant of an amorphous aluminum-arsenate phase (AlAsO4·3.5H2O) at 25 °C" Hydrometallurgy Volumes 2014, 144–145, Pages 63–68. doi:10.1016/j.hydromet.2014.01.001
  2. ^ Aluminum arsenate at Chemister
  3. ^ Chemistry of Arsenic, Antimony, and Bismuth, Edited by N. C. Norman. page 131,
  4. ^ "Alarsite".
  5. ^ Katz, Gerald; Kedesdy, Horst (1954). "A new synthetic hydrate of aluminum arsenate" (PDF). American Mineralogist. 39 (11–12)): 1005–1017.
  6. ^ B. Sharan "A new modification of aluminum ortho-arsenate" Acta Crystallogr. 1959, vol. 12, 948-949. doi:10.1107/S0365110X59002729
Quelle: http://en.wikipedia.org/wiki/Aluminium_arsenate