Chemical elements
    Physical Properties
    Chemical Properties
      Molybdenum Hexafluoride
      Molybdenum Dichloride
      Molybdenum Trichloride
      Molybdenum Tetrachloride
      Molybdenum Pentachloride
      Molybdenum Oxychlorides
      Chlormolybdic Acids
      Molybdenum Dibromide
      Molybdenum Tribromide
      Molybdenum Tetrabromide
      Molybdenum Oxybromide
      Molybdenum Di-iodide
      Molybdenum Oxyiodide
      Iodomolybdic Acid
      Molybdenum Sesquioxide
      Molybdenum Dioxide
      Molybdenum Oxide Blue
      Molybdenum Trioxide
      Aluminium Molybdates
      Ammonium Molybdate
      Ammonium Dimolybdate
      Ammonium Paramolybdate
      Ammonium Trimolybdate
      Ammonium Tetramolybdate
      Ammonium Octamolybdate
      Barium Molybdates
      Barium Paramolybdate
      Barium Trimolybdate
      Barium Tetramolybdate
      Barium Octamolybdate
      Barium Nonamolybdate
      Beryllium Molybdate
      Bismuth Molybdates
      Cadmium Molybdates
      Caesium Molybdates
      Calcium Molybdate
      Calcium Trimolybdate
      Calcium Tetramolybdate
      Calcium Octamolybdate
      Chromium Molybdates
      Cobalt Molybdates
      Cobalt Dimolybdate
      Cobalt Trimolybdate
      Copper Molybdates
      Ferrous Molybdate
      Ferric Molybdate
      Indium Molybdate
      Lead Molybdates
      Lithium Molybdate
      Lithium Dimolybdate
      Lithium Paramolybdate
      Lithium Trimolybdate
      Lithium Tetramolybdate
      Magnesium Molybdates
      Magnesium Paramolybdate
      Magnesium Trimolybdate
      Manganese Molybdate
      Mercurous Molybdates
      Nickel Molybdates
      Potassium Molybdate
      Potassium Dimolybdate
      Potassium Paramolybdate
      Potassium Trimolybdate
      Potassium Tetramolybdate
      Potassium Octamolybdate
      Potassium Decamolybdate
      Rhodium Molybdates
      Rubidium Molybdate
      Rubidium Dimolybdate
      Rubidium Paramolybdate
      Rubidium Trimolybdate
      Rubidium Tetramolybdates
      Silver Molybdates
      Normal Silver Molybdate
      Sodium Molybdate
      Sodium Dimolybdate
      Sodium Paramolybdate
      Sodium Trimolybdate
      Sodium Tetramolybdate
      Sodium Iodomolybdate
      Strontium Molybdate
      Thallous Molybdate
      Thallous Paramolybdate
      Thallous Tetramolybdate
      Thorium Molybdate
      Uranium Molybdates
      Uranyl Octamolybdate
      Zinc Molybdates
      Zinc Trimolybdate
      Zinc Tetramolybdate
      Zinc Octamolybdate
      Zirconium Molybdate
      Permolybdic Acid
      Molybdenum Sesquisulphide
      Molybdenum Disulphide
      Dimolybdenum Pentasulphide
      Molybdenum Trisulphide
      Molybdenum Tetrasulphide
      Ammonium Thiomolybdates
      Ammonium Molybdosulphites
      Potassium Thiomolybdate
      Potassium Thiodimolybdate
      Potassium Dithiodioxymolybdate
      Potassium Molybdosulphite
      Sodium Thiomolybdates
      Sodium Molybdosulphites
      Molybdenum Sulphates
      Molybdenum Selenide
      Complex Molybdoselenites
      Chromates of Molybdenum
      Molybdenum Phosphide
      Molybdic Metaphosphate
      Heteropoly-compounds with Phosphorus
      12-Molybdophosphoric Acid
      9-Molybdophosphoric Acid
      172-Molybdophosphoric Acid
      Molybdenum Carbides
      Molybdenum Carbonyl
      Reddish-violet Salts
      Yellow Salts
      Thiocyanates of Molybdenum
      Molybdenum Monosilicide
      Molybdenum Sesquisilicide
      Molybdenum Disilicide
      Molybdosilicic Acid and Molybdosilicates
      12-Molybdosilicic Acid
    PDB 1aa6-1qh8
    PDB 1r27-2jir
    PDB 2min-3unc
    PDB 3uni-4f6t

Thiocyanates of Molybdenum

Thiocyanates containing molybdenum as a cation are not known, but compounds similar to the complex cyanides, in which the metal figures as the central atom of a complex anion, have been prepared.

  1. Compounds containing trivalent molybdenum of the, type R3[Mo(SCN)6].xH2O. Many salts which appear to be of this type have been prepared by Sand and Maas, who formulate them with (OH) or (H2O) of constitution thus: [Mo(SCN)6.OH]R3.xH2O and [Mo(SCN)6.H2O]R3.xH2O. The potassium salt, K3Mo(SCN)6.4H2O, may be prepared by the action of potassium thiocyanate on the double chloride, K3MoCl6. It yields orange-coloured crystals, readily soluble in water, and which readily lose water of crystallisation, becoming dark red in colour or, if heated to complete dehydration, almost black. The method of preparation used by Sand and Maas involved the electrolysis of potassium molybdate and thiocyanate in hydrochloric acid solution. The sodium and ammonium salts may be obtained by either of the two methods described, while insoluble salts of copper, nickel, silver, and zinc are obtained by addition of solutions of these metals to a solution of the complex alkali salt. Many metal-ammine derivatives and compounds with organic bases have been described.

    The alkali hexathiocyanates are not isomorphous amongst themselves, but each molybdenum salt is isomorphous with the corresponding chromium salt thus:


    The thallium salt, Tl3Mo(SCN)6, is formed as an amorphous, light yellow precipitate when thallium nitrate is added to a solution of the potassium salt.

    The molybdenum in these salts may be oxidised by ammoniacal silver nitrate and the equivalent of the molybdenum calculated from the amount of silver liberated; the results obtained indicate a trivalent molybdenum atom.
  2. Compounds containing tetravalent molybdenum. When precipitated molybdenum disulphide is dissolved in a warm solution of potassium cyanide, a deep green liquid is formed which on concentration yields slender black needles of composition MoS2(CN)2.2KCN. The compound is also obtained by boiling a solution of potassium thio-molybdate with an excess of potassium cyanide until the red colour completely changes to green. When heated with acids it yields hydrocyanic acid and molybdenum disulphide. The green solution is precipitated with alcohol, a greenish oil separating which gradually solidifies. An examination of the reaction between potassium cyanide and molybdenum disulphide suggests that three different compounds may be formed according to the length of time allowed for the reaction, namely, Mo2S3.6KCN.5H2O, which forms green silky crystals when the action goes for a short time; Mo2SO(CN)2.4KCN.4H2O, obtained as beautiful reddish-brown needles by evaporating the reacting mixture in a vacuum; and Mo3S4(CN)3.5KCN.7H2O, which results in large black crystals (green by transmitted light) on allowing the preceding salt to remain in contact with the mother-liquor over sulphuric acid. The mode of formation and the properties of these compounds indicate the presence of tetravalent molybdenum, but in order to establish their true nature further investigation is desirable.
  3. Compounds containing pentavalent molybdenum. When a solution of ammonium molybdate and ammonium thiocyanate is reduced electrolytically and the resulting liquid extracted with ether, all the red- colouring substances pass into the latter; on adding pyridine, a compound, of composition Mo(OH)2(SCN)3(C5H5N)2, is obtained in the form of dark brownish-red feathery aggregates of crystals, which may be recrystallised from hot alcohol, and which melt and decompose at 182° C. Similar compounds with other organic bases have been described.

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