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

Copper Arsenites






A natural arsenite known as trippkeite, of composition nCuO.As2O3, is found in the form of bluish-green tetragonal crystals (a:c = 1:0.9160) associated with cuprite in Chile. By arsenious oxide under various conditions products are obtained which contain more or less pure arsenites.


Copper Orthoarsenite, Cu3(NaO3)2

Copper Orthoarsenite, Cu3(NaO3)2.2H2O, was obtained by Sharpies by boiling a solution of copper sulphate with arsenious oxide and sodium carbonate, and drying the precipitate at 100° C. At 150° C. it still retains water. It is soluble in dilute acids and alkalis and in ammonia, but is decomposed by concentrated alkali. The anhydrous salt was described by Stavenhagen as resulting when alcoholic solutions of cupric chloride and potassium orthoarsenite were mixed, the precipitate being dried at 100° C. The product darkened in colour in contact with water and its purity and identity are doubtful.

The pigment first prepared by Scheele in 1778, and known as Scheele's green, is essentially cupric orthoarsenite containing excess of cupric oxide, the composition varying with the mode of preparation. It is best obtained by a method similar to that used by the discoverer. Hot aqueous solutions of arsenious oxide and copper sulphate are mixed and to the mixture is added, in small successive portions, a solution of potassium carbonate, until the precipitate attains its maximum colour intensity. After filtration, the precipitate is washed with hot water and dried at a moderate temperature. Similar products are obtained by treating aqueous arsenious acid or potassium hydrogen di-arsenite with a hot aqueous or ammoniacal solution of a copper salt. The use of this pigment, owing to its poisonous nature, is prohibited. It resembles Emerald green, but is in every way inferior to that pigment. Pigments prepared by slightly modified processes, but of essentially the same composition, are known under many designations, including Swedish green, Vienna green, Mitis green and Veronese green. Bloxam stated that when the green precipitate was dried in the air, its composition corresponded with copper pyroarsenite, Cu2As2O5 or 2CuO.As2O3, with 2.89H2O, and when dried at 100° C. to yield Scheele's green it was CuHNaO3 (copper monohydrogen arsenite). Other investigators maintain that the composition approximates more closely to the normal orthoarsenite; but it is undoubtedly variable and the amount of cupric oxide present increases with the amount of alkali used in its preparation. The compound decomposes on heating, giving off arsenious oxide and water and leaving a residue of copper arsenide and arsenate.

Efforts to prepare an improved Scheele's green resulted in 1814 in the production of Emerald green, cupric aceto-arsenite, the colour of which is a nearly normal green, slightly verging upon bluish-green. It is brighter and more opaque than Scheele's green, and like it is extremely poisonous. It is generally prepared by adding a solution of verdigris in acetic acid to a boiling solution of white arsenic; on continued ebullition the Emerald green is deposited. A mixture of copper sulphate, acetic acid and potassium arsenite may also be employed. The product must be washed free of soluble salts with boiling water. The pigment is known also under the names Schweinfurt green and Paris green. The composition approximates very nearly to 3Cu(AsO2)2.Cu(C2H3O2)2. The pigment dissolves in boiling dilute mineral acids. After boiling for some time with a large excess of arsenious oxide solution, the substance suddenly becomes paler in colour and is converted to anhydrous copper metarsenite, Cu(AsO2)2, a grey crystalline powder. The dihydrate, Cu(AsO2)2.2H2O, was obtained by Stavenhagen as a pale green amorphous precipitate by adding a solution of arsenious oxide in 50 per cent, aqueous alcohol to a slightly acid solution of cupric chloride in alcohol. The precipitate was dried over sulphuric acid. At 100° C. it lost 1 molecule of water; above this temperature arsenious oxide was also liberated.
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