Known since the Middle Ages by the name plumb dulcis, the production of lead(II) nitrate from either metallic lead or lead oxide in nitric acid was small-scale, for direct use in making other lead compounds. In the 19th century lead(II) nitrate began to be produced commercially in Europe and the United States. Historically, the main use was as a raw material in the production of pigments for lead paints, but such paints have been superseded by less toxic paints based on titanium dioxide. Other industrial uses included heat stabilisation in nylon and polyesters, and in coatings of photothermographic paper. Since around the year 2000, lead(II) nitrate has begun to be used in gold cyanidation.
Lead(II) nitrate is toxic, an oxidising agent, and is categorised as probably carcinogenic to humans by the International Agency for Research on Cancer. Consequently, it must be handled and stored with the appropriate safety precautions to prevent inhalation, ingestion and skin contact. Due to its hazardous nature, the limited applications of lead(II) nitrate are under constant scrutiny.
In 1597, the German alchemist Andreas Libavius first described the compound, coining the medieval names of plumb dulcis and calx plumb dulcis, meaning "sweet lead", because of its taste. Although originally not understood during the following centuries, the decrepitation property of lead(II) nitrate led to its use in matches and special explosives such as lead azide.
The production process was and still is chemically straightforward, effectively dissolving lead in aqua fortis (nitric acid), and subsequently harvesting the precipitate. However, the production remained small-scale for many centuries, and the commercial production of lead(II) nitrate as raw material for the manufacture of other lead compounds was not reported until 1835. In 1974, the U.S. consumption of lead compounds, excluding pigments and gasoline additives, was 642 tons.
Apart from lead(II) nitrate, lead(II) acetate is the only other common soluble lead compound. Nearly all other lead compounds are insoluble in water, even when coupled with commonly very soluble anions. For example, lead(II) chloride, lead(II) bromide and lead(II) iodide, collectively known as lead halides, are merely weakly soluble in water (less than 0.01 mol/l) at room temperature, and only slightly more closer to the boiling point. This means that lead(II) nitrate has particular importance as a starting point for the production of insoluble lead compounds via double decomposition.
Hot solutions of lead halides can be brought to precipitation on cooling to create feathery, iridescent crystals suspended in water, the colour of which crystal depends on the particular halide (chloride = white, bromide = buff, iodide = yellow). These crystals appear suddenly, requiring only a nucleation site once the temperature of the solution has fallen sufficiently for the solution to be supersaturated. This effect is used for demonstration of solubility in classrooms.
When concentrated sodium hydroxide solution is added to lead(II) nitrate solution, basic nitrates are formed, even well past the equivalence point. Up through the half equivalence point, Pb(NO3)2·Pb(OH)2 predominates, then after this point Pb(NO3)2·5Pb(OH)2 is formed. No simple Pb(OH)2 is formed up to at least pH 12.
The crystal structure of solid lead(II) nitrate has been determined by neutron diffraction. The compound crystallises in the cubic system with the lead atoms in a face-centered cubic system. Its space group is Pa3Z=4 (Bravais lattice notation), with each side of the cube with length 784 picometres.
The black dots represent the lead atoms, the white dots the nitrate groups 27 picometres above the plane of the lead atoms, and the blue dots the nitrate groups the same distance below this plane. In this configuration, every lead atom is bonded to twelve oxygen atoms (bond length: 281 pm). All N–O bond lengths are identical, at 127 picometres.
Research interest in the crystal structure of lead(II) nitrate was partly based on the possibility of free internal rotation of the nitrate groups within the crystal lattice at elevated temperatures, but this did not materialise.
The complex formed by lead(II) nitrate, lead(II) perchlorate and a bithiazole bidentate N-donor ligand is binuclear, with a nitrate group bridging the lead atoms with coordination number of 5 and 6. One interesting aspect of this type of complexes is the presence of a physical gap in the coordination sphere; i.e., the ligands are not placed symmetrically around the metal ion. This is potentially due to a lead lone pair of electrons, also found in lead complexes with an imidazole ligand.
This type of chemistry is not unique to the nitrate salt; other lead(II) compounds such as lead(II) bromide also form complexes, but the nitrate is frequently used because of its solubility properties and its bidentate nature.
In nitric acid treatment of lead-containing wastes, e.g., in the processing of lead–bismuth wastes from lead refineries, impure solutions of lead(II) nitrate are formed as by-product. These solutions are reported to be used in the gold cyanidation process.
On a laboratory scale, lead(II) nitrate provides one of two convenient and reliable sources of dinitrogen tetroxide. By carefully drying lead(II) nitrate and then heating it in a steel vessel, nitrogen dioxide is produced along with dioxygen following to the decripitation equation shown above. Alternatively, nitrogen dioxide is formed when concentrated nitric acid is added to copper turnings; in this case, substantial nitrogen monoxide can also be produced. In either case, the resulting nitrogen dioxide exists in equilibrium with its dimer:
To improve the leaching process in the gold cyanidation, lead(II) nitrate solution is added. Although a bulk process, only limited amounts (10 to 100 milligrams lead(II) nitrate per kilogram gold) is required. Both the cyanidation itself, as well as the use of lead compounds in the process, are deemed controversial due to the compounds' toxic nature.
To prevent inhalation, ingestion and exposure to skin, lead(II) nitrate must be handled in a fume cupboard, with face, body and hand protection. Special instructions for handling are included in all Material safety data sheets (MSDS). After use, all material and its containers must be disposed of as hazardous waste. Spillage and release to the environment must be avoided.