Chemical elements
    Physical Properties
    Chemical Properties
      Lead Tetramethyl
      Lead Tetraethyl
      Lead Tetraphenyl
      Lead Ethoxide
      Lead Fluoride
      Lead Tetrafluoride
      Hydrofluoplumbic Acid
      Lead Chloride
      Lead Chloride Double Salts
      Basic Lead Chlorides
      Lead Tetrachloride
      Ammonium Plumbichloride
      Lead Chlorite
      Lead Chlorate
      Lead Perchlorate
      Lead Dibromide
      Double Salts of Lead Bromide
      Basic Lead Bromides
      Lead Bromate
      Lead Iodide
      Lead Iodide Complex Salts
      Basic Lead Iodides
      Lead Tetra-iodide
      Lead Iodate
      Lead Periodates
      Lead Suboxide
      Lead Monoxide
      Lead Hydroxides
      Lead Dioxide
      Plumbic Acids
      Hexahydroxyplumbic Acid
      Colloidal Plumbic Acid
      Potassium Plumbate
      Lead Plumbate
      Calcium Orthoplumbate
      Lead Orthoplumbate
      Red Lead
      Metaplumbic Acid
      Calcium Metaplumbate
      Lead Metaplumbate
      Basic Lead Plumbate
      Lead Sulphide
      Lead Sulphohalides
      Lead Polysulphide
      Lead Sulphite
      Lead Sulphates
      Lead Sulphate
      Basic Lead Sulphates
      Lead Hydrogen Sulphate
      Plumbic Sulphate
      Lead Persulphate
      Lead Thiosulphate
      Lead Dithionate
      Lead Selenide
      Lead Selenite
      Lead Selenate
      Lead Telluride
      Lead Tellurite
      Lead Azide
      Lead Azoimide
      Lead Hydrazoate
      Lead Imide
      Lead Hyponitrite
      Lead Nitrites
      Lead Nitrate
      Lead saltpetre
      Basic Lead Nitrates
      Lead Hypophosphite
      Lead Phosphite
      Lead Orthophosphate
      Lead Monohydrogen Phosphate
      Lead Dihydrogen Phosphate
      Lead Pyrophosphate
      Lead Metaphosphate
      Lead Arsenite
      Lead Orthoarsenate
      Lead Hydrogen Arsenate
      Lead Pyroarsenate
      Lead Antimonate
      Lead Carbonate
      White Lead
      Lead Formate
      Lead Acetate
      Sugar of Lead
      Complex Lead Acetates
      Plumbic Acetate
      Lead Tetra-acetate
      Lead Oxalate
      Lead Tartrate
      Lead Silicates
      Lead Borates
      Normal Lead Chromate
      Lead Dichromate
      Basic Lead Chromate
      Lead Molybdate
      Lead Tungstate
      Lead Metatungstate
      Lead Diuranate
      Lead Peruranate
    PDB 1afv-3qjk

Lead Nitrate, Pb(NO3)2

Lead Nitrate, Pb(NO3)2, or lead saltpetre, has long been known, and is mentioned in the Alchymia of Libavius by the name calx plumb. dulcis. It is obtained by dissolving lead, lead oxide, or lead carbonate in warm, dilute nitric acid, and crystallising the solution; commercially, lead scale or litharge is used for this purpose. The salt separates from aqueous solution in regular octahedra, in combinations of these forms with the cube, or in dodekahedra. Monoclinic crystals of lead nitrate have also been observed. According to Hauer, the form and transparency of the crystals depends upon the rate of cooling and degree of acidity of the solution. It was pointed out by Retgers that crystals separated from an aqueous solution are porcelain-like, but that from a solution acidified by nitric acid they are clear; the explanation being that in the former case they are slightly basic owing to hydrolysis, whilst in the latter case they are pure.

Lead nitrate has a density of 4.531 at 24° C.; its refractive index for sodium light at 20° C. is 1.7820; its molecular heat of formation from its elements is 105,500 calories. Lead nitrate decrepitates when heated, detonates on red-hot charcoal, and deflagrates when rubbed with sulphur. The action of heat upon lead nitrate has been investigated by Baekeland, who finds that when the salt is heated to 35.7° C. in an evacuated and sealed glass tube, brown fumes are evolved, but are completely reabsorbed when the tube is cooled, according to the reaction

Pb(NO3)2PbO + O + 2NO2.

The connection between temperature and dissociation pressure was found to be as follows:

Temperature ° C.223230250274296357448
Pressure mm. of mercury6.26.911.832.678.4514.01180.0

If, however, the salt is kept at 357° C. its power of evolving gas so as to regenerate the pressure after evacuation is much diminished, until the pressure attainable falls from 514 mm. to 260 mm. The residue is now slightly yellow and is a basic lead nitrate of the composition 3Pb0.2N2O5 or 2Pb(NO3)2.PbO. After the salt has been left at the same temperature in communication with the vacuum pump for ten days its dissociation pressure falls to zero, whilst its composition becomes 3PbO.N2O5 or Pb(NO3)2.2PbO. This second basic salt loses all its nitrous fumes at a red heat, leaving a residue of oxide. So it is shown that lead nitrate is decomposed by heat in stages, thus:

3Pb(NO3)2 → 2Pb(NO3)2.PbOPb(NO3)2.2PbO → 3PbO.

The introduction of oxygen or nitrogen peroxide into the dissociation tube before the salt is heated, retards dissociation in accordance with the law of mass action. According to Colson, perfectly dried lead nitrate shows no sign of decomposition in a vacuum till 283° C. is reached. On account of its decomposition, the melting-point of lead nitrate is unknown. This salt dissolves readily in water; the following solubility table includes the results of Mulder, Kremers, Michel and Kraft, and Euler:

Temperature ° C.Grams Pb(NO6)2 per 1000 grams of:
MulderKremersMichel and Kraft.

The density of a saturated solution at 17° C. is 1.405 (Euler), and at 25.3° C. compared with water at the same temperature 1.458.

The solubility of lead nitrate in water is much diminished by the addition of nitric acid, so that its aqueous solution is precipitated by concentrated nitric acid. The following figures show the influence of nitric acid on this solubility at 25° C.:

Mols. HNO3 per litre02.024.648.7714.35
Mols. Pb(N03)2 per litre1.630.5360.1870.0420.0017

The densities of lead nitrate solutions of various strengths are as follow:

Per cent. Pb(N03)25101520253035
Relative densities at 15° C (water at 4°C. = 1) 1.0451.0951.1471.2041.2681.336-
Relative densities8 at 17.5° C. (water at 17.5° C. = 1) 1.0401.0921.1441.2001.2631.3331.409

The solution of lead nitrate in water is accompanied by lowering of temperature; the heat of solution of 1 molecule Pb(N03)2 in 400 molecules of water is -7,600 calories, and of 1 molecule in 930-1860 molecules of water -8,200 calories.

From numerous estimations of depressions of freezing-point and conductivities of solutions of lead nitrate of various concentrations it is concluded that this salt is not appreciably hydrolysed at 25° C., but undergoes ionisation in two stages, thus:

  1. Pb(NO3)2Pb(NO3) + NO3'.
  2. Pb(NO3)' → Pb•• + NO3'.

The extent of ionisation at 25.3° C. has been estimated by Lewis, with the following results:

Mol. Pb(NO3)2 per litre10.
Concentration Pb•• ions0.05030.04080.03540.01680.0054
Percentage ionisation510143454

Warm solutions of lead nitrate are appreciably hydrolysed. Thus Walker and Aston estimated, by measurement of the inversion of cane sugar, that a N/2 solution of this salt is hydrolysed to 0.15 per cent, at 60° C.; Long, however, found only 0.1 per cent, hydrolysis of a similar solution at 85° C.

The solubilities of lead nitrate in aqueous and absolute ethyl alcohol and in methyl alcohol are as follow:

SolventGrams Pb(NO3)2 per 1000 grams solvent at
4° C.8° C.22° C.40° C.50° C.
Aqueous ethyl alcohol (density 0.9282)4.965.828.7712.814.9
Absolute ethyl alcohol--0.04 (20.5° C.)--
Absolute methyl alcohol--1.37--

Lead nitrate has an astringent taste. It is used in calico printing, as a mordant in dyeing, and for the manufacture of chrome yellow.

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