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

Lead Arsenites






An investigation of the ternary system PbO-As2O3-H2O at 25° C. gives evidence of the formation of the metarsenite, Pb(AsO2)2, only. Several other well-defined arsenites, are known, however.


Lead Orthoarsenite, Pb3(NaO3)2

Lead Orthoarsenite, Pb3(NaO3)2, is obtained as a white precipitate on adding a solution of basic lead acetate to a boiling aqueous solution of arsenious oxide, or of potassium tetrarsenite, or by the action of an alkali plumbite on an alkali arsenite. When dried in a dark air oven the arsenite remains white, but when exposed to light some specimens turn brown, a change which has been attributed to reduction of the lead to suboxide, but some arsenate and free arsenic are formed. All specimens of the orthoarsenite are not photo-sensitive. A dry mixture of litharge and arsenious oxide is remarkably sensitive, arsenic being liberated in the reaction which occurs; and when the arsenite is prepared from lead hydroxide by heating with arsenious oxide and dilute aqueous sodium hydroxide, the product is also light-sensitive. The commercial product and those obtained by the methods described above are not sensitive. It has been suggested that in the latter case the salt has the composition 3Pb(OH)2.As2O3. No other metallic arsenite has been observed to be photo-sensitive. Lead arsenite may be used as a light-sensitive agent in photographic, photometric and actinometric compositions, the exposed negative being developed by dry heating or wet reduction; other light-sensitive substances may be admixed.

When a mixture of litharge and arsenious oxide is heated, formation of lead orthoarsenite begins at 250° C., but oxidation occurs, and with rising temperature increasing amounts of the orthoarsenate are formed, the latter being the sole product above 450° C.

The Swedish mineral Jinnemanite contains lead orthoarsenite in combination with lead chloride, the composition being 3Pb3(NaO3)2.PbCl2. It occurs in dark grey or black prismatic crystals belonging to the hexagonal system and of axial ratio a:c = 1:0.6880.

Lead arsenite is readily obtained by an electrolytic process. The catholyte may be a 15 per cent, solution of sodium hydroxide or of a sodium salt, or a 30 per cent, solution of potassium hydroxide, the cathode being of nickel. The anolyte is a solution of an alkali arsenite neutralised towards phenolphthalein by means of acetic acid, and the anode is of lead. The cathode space is separated by a diaphragm of vegetable parchment. Ormont obtained a current yield of 97 per cent., and the average energy yield amounted to 1 kg. per kilowatt-hour.

The monohydrate, Pb3(NaO3)2.H2O, was described by Stavenhagen, who obtained it by drying in air the precipitate resulting from the addition of potassium orthoarsenite to a dilute aqueous solution of lead nitrate.

Lead Pyroarsenite, Pb2As2O5

Lead Pyroarsenite, Pb2As2O5, is a white powder formed by decomposing normal lead acetate with ammoniacal arsenious oxide solution, or with potassium tetrarsenite or pyroarsenite. According to Simon, it is also formed by the combination of arsenious oxide vapour with lead oxide; Stavenhagen, however, found the product to be merely a mixture of oxides. When heated, lead pyroarsenite fuses to form a yellow glass. It liberates ammonia from ammonium salts even in the cold.

Lead Metarsenite, Pb(AsO2)2

Lead Metarsenite, Pb(AsO2)2, is formed from a hot saturated solution of arsenious oxide in ammonia by addition of a neutral lead salt. It forms microscopic prisms of density 5.85 at 23° C., very slightly soluble in water. When heated in an inert atmosphere it decomposes readily into lead oxide and arsenious oxide.

A tetrarsenite, Pb3As4O9.3H2O, was described by Bloxam but could not be obtained by Stavenhagen.

A colloidal solution of lead arsenite has been obtained by the following method. A solution of lead acetate is treated with a 10 per cent, solution of sodium lysalbinate, and after washing the precipitate with hot water, it is dissolved in a dilute aqueous solution of sodium hydroxide containing sodium dihydrogen arsenite. The liquid, after keeping for some hours, is filtered and dialysed until the outside liquor is free from arsenic. The solution in the dialyser is concentrated, mixed with alcohol and ether, and dried over sulphuric acid in a vacuum. A pale yellow horny mass remains, which dissolves readily in water to form a sol.
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