Chemical elements
  Arsenic
      Occurrence
      Ubiquity
      History
    Isotopes
    Energy
    Production
    Application
    Physical Properties
    Chemical Properties
      Aluminium Arsenide
      Antimony Arsenides
      Barium Arsenide
      Bismuth Arsenides
      Cadmium Arsenides
      Calcium Arsenide
      Cerium Arsenide
      Chromium Arsenides
      Cobalt Arsenides
      Copper Arsenides
      Gold Arsenides
      Iridium Arsenide
      Iron Arsenides
      Lead Arsenides
      Lithium Arsenide
      Magnesium Arsenide
      Manganese Arsenides
      Mercury Arsenides
      Molybdenum Arsenide
      Nickel Arsenides
      Niobium Arsenide
      Palladium Di-arsenide
      Platinum Arsenides
      Potassium Arsenides
      Rhodium Arsenide
      Ruthenium Arsenide
      Silver Arsenides
      Sodium Arsenide
      Strontium Arsenide
      Thallium Arsenide
      Tin Arsenides
      Tungsten Arsenide
      Uranium Arsenide
      Zinc Arsenides
      Arsenic Subhydride
      Arsenic Monohydride
      Arsenic Trihydride
      Arsenic Trifluoride
      Arsenic Pentafluoride
      Arsenic Nitrosyl Hexafluoride
      Arsenic Trichloride
      Arsenic Oxychloride
      Arsenic Pentachloride
      Arsenic Tribromide
      Arsenic Oxybromide
      Arsenic Moniodide
      Arsenic Diiodide
      Arsenic Triiodide
      Arsenic Pentiodide
      Arsenic Suboxide
      Arsenious Oxide
      Aluminium Arsenite
      Ammonium Arsenites
      Antimony Arsenite
      Barium Arsenites
      Beryllium Arsenite
      Bismuth Arsenite
      Cadmium Arsenites
      Calcium Arsenites
      Chromic Arsenite
      Cobalt Arsenites
      Copper Arsenites
      Gold Arsenites
      Iron Arsenites
      Lead Arsenites
      Lithium Arsenite
      Magnesium Arsenites
      Manganese Arsenites
      Mercury Arsenites
      Nickel Arsenites
      Palladium Pyroarsenite
      Platinum Arsenites
      Potassium Arsenites
      Arsenites of Rare Earth Metals
      Rubidium Metarsenite
      Silver Arsenites
      Sodium Arsenites
      Strontium Arsenites
      Thallous Orthoarsenite
      Tin Arsenites
      Titanyl Tetrarsenite
      Tungsto-arsenites
      Uranyl Metarsenite
      Zinc Arsenites
      Zirconium Arsenite
      Arsenic Tetroxide
      Arsenic Pentoxide
      Aluminium Arsenates
      Ammonium Arsenates
      Barium Arsenates
      Beryllium Arsenates
      Bismuth Arsenates
      Cadmium Arsenates
      Caesium Arsenate
      Calcium Arsenates
      Chromium Arsenates
      Cobalt Arsenates
      Copper Arsenates
      Hydroxylamine Orthoarsenate
      Iron Arsenates
      Lead Arsenates
      Lithium Arsenates
      Magnesium Arsenates
      Manganese Arsenates
      Mercury Arsenates
      Molybdenum Arsenates
      Nickel Arsenates
      Palladium Arsenate
      Platinic Arsenate
      Potassium Arsenates
      Rare Earth Metals Arsenates
      Rhodium Arsenate
      Rubidium Arsenates
      Silver Arsenates
      Sodium Arsenates
      Strontium Arsenates
      Thallium Arsenates
      Thorium Arsenates
      Tin Arsenates
      Titanyl Arsenate
      Tungsto-arsenic Acids
      Uranium Arsenates
      Vanado-arsenates
      Zinc Arsenates
      Zirconium Arsenates
      Perarsenates
      Arsenic and Sulphur
      Arsenic Subsulphide
      Tetrarsenic Trisulphide
      Arsenic Disulphide
      Arsenic Trisulphide
      Arsenic Pentasulphide
      Thioarsenates
      Ammonium Thioarsenates
      Antimony Thioarsenate
      Barium Thioarsenates
      Beryllium Thioarsenate
      Bismuth Thioarsenate
      Cadmium Thioarsenates
      Calcium Thioarsenates
      Cerium Thioarsenates
      Chromium Thioarsenate
      Cobalt Thioarsenate
      Copper Thioarsenates
      Gold Thioarsenates
      Iron Thioarsenates
      Lead Thioarsenates
      Lithium Thioarsenates
      Magnesium Thioarsenates
      Manganese Thioarsenates
      Mercury Thioarsenates
      Molybdenum Thioarsenates
      Nickel Thioarsenates
      Platinic Thioarsenate
      Potassium Thioarsenates
      Silver Thioarsenates
      Sodium Thioarsenates
      Strontium Thioarsenates
      Thallium Orthothioarsenate
      Tin Thioarsenates
      Uranyl Thioarsenate
      Yttrium Thioarsenate
      Zinc Thioarsenates
      Zirconium Thioarsenate
      Trioxythioarsenic Acid
      Dioxydithioarsenic Acid
      Oxytrithioarsenic Acid
      Arsenic Monosulphatotrioxide
      Arsenic Disulphatotrioxide
      Arsenic Trisulphatotrioxide
      Arsenic Tetrasulphatotrioxide
      Arsenic Hexasulphatotrioxide
      Arsenic Octasulphatotrioxide
      Complex salts of Sulphato-compounds of Arsenic
      Arsenic Nitride
      Arsenic Imide
      Arsenic Amide
      Arsenic Phosphides
      Arsenic oxyphosphides
      Arsenic Phosphate
      Arsenic Thiophosphate
      Arsenic Tricarbide
      Arsenic Pentasilicide
      Boron Arsenate
    Detection of Arsenic
    Estimation of Arsenic
    Physiological Properties
    PDB 1b92-1ihu
    PDB 1ii0-1tnd
    PDB 1tql-2hmh
    PDB 2hx2-2xnq
    PDB 2xod-3htw
    PDB 3hzf-3od5
    PDB 3ouu-9nse

Silver Arsenates






Silver nitrate reacts with solutions of arsenic acid or arsenates, giving a chocolate-coloured precipitate of silver orthoarsenate, Ag3AsO4, containing a small proportion of silver nitrate, possibly in solid solution. The adsorption of silver nitrate is prevented by the presence of ammonium nitrate. The precipitation is incomplete in acid solution. The orthoarsenate cannot be completely dried except by fusion.

When precipitated from a boiling solution of silver nitrate by concentrated aqueous arsenic acid, the precipitate is deep purple in colour. As usually prepared it forms cubic crystals, which may be tetra-, hexa- or dodeca-hedral. The unit cell contains 2 molecules and has a side 6.12 A. The crystals have density 6.657 at 25° C. The solubility in water at 20° C. is 0.0085 g. per litre.

When heated, the salt first melts and at a higher temperature it decomposes to form silver; reduction to the metal occurs more readily when heated with carbon. Partial reduction also occurs when the orthoarsenate is treated with formaldehyde or with ferrous sulphate solution; in the former case silver is formed, but in the latter silver suboxide.

Silver orthoarsenate dissolves in hydrochloric acid, forming arsenic trichloride, and in nitric acid with partial conversion to nitrato-arsenate, which may be separated by fractional crystallisation, silver orthoarsenate crystallising out first and then the nitrato-arsenate; the latter, in contact with water, reverts to silver nitrate and silver orthoarsenate. The latter is also soluble in acetic acid, and in aqueous ammonia or ammonium carbonate. By crystallising the solution in ammonia over a mixture of quicklime and sal-ammoniac, colourless needles of silver tetrammino-orthoarsenate, Ag3AsO4.4NH3, are obtained; these lose ammonia in the air and turn reddish-brown.

When silver nitrate solution is dropped on a gelatin gel containing an alkali arsenate, periodic precipitation of silver orthoarsenate occurs only in darkness; if the gels are exposed to the light a continuous precipitate is formed. Colloidal silver orthoarsenate has been prepared by mixing solutions of silver nitrate and sodium protalbinate and dissolving the precipitate formed in dilute aqueous sodium hydroxide containing sodium monohydrogen orthoarsenate. After dialysis in the dark, the solution was evaporated in vacuo over sulphuric acid; the powder obtained gave a hydrosol which was dark green by reflected light and red by transmitted light.


Silver Monohydrogen Orthoarsenate, Ag2HAsO4

Silver Monohydrogen Orthoarsenate, Ag2HAsO4, has not been obtained in the pure condition.

Silver Dihydrogen Orthoarsenate, AgH2AsO4

Silver Dihydrogen Orthoarsenate, AgH2AsO4, is readily obtained as white monoclinic crystals from a solution of arsenic acid (of composition H3AsO4.H2O) saturated with silver orthoarsenate. If the solution is saturated with the silver orthoarsenate at a temperature a little below 100° C., it deposits orange-red hexagonal prisms similar to those of silver monohydrogen phosphate; these are probably the monohydrogen arsenate, but they decompose rapidly in the presence of water. Also when the dihydrogen arsenate is heated to 100° C. it first turns red, probably forming the monohydrogen salt, but rapidly loses water to form silver metarsenate, AgNaO3, as a white powder.

When a syrupy solution of silver orthoarsenate in arsenic acid is heated above 100° C. it yields a white granular powder of composition Ag2O.2As2O5, which is decomposed by water into silver orthoarsenate and arsenic acid.
© Copyright 2008-2012 by atomistry.com