Lead(II) thiocyanate is a

compound Compound may refer to: Architecture and built environments * Compound (enclosure), a cluster of buildings having a shared purpose, usually inside a fence or wall ** Compound (fortification), a version of the above fortified with defensive struc ...

, more precisely a

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

, with the formula Pb(SCN)₂. It is a white crystalline solid, but will turn yellow upon exposure to light. It is slightly soluble in water and can be converted to a basic salt (Pb(CNS)₂·Pb(OH)₂ when boiled. Salt crystals may form upon cooling. Lead thiocyanate can cause lead poisoning if ingested and can adversely react with many substances. It has use in small explosives, matches, and dyeing. Lead(II)Thiocyanate

Lead(II) thiocyanate is reasonably soluble at room temperature, thus it may be difficult to identify in a solution with low

concentration In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', ''molar concentration'', '' number concentration'', ...

of lead(II) thiocyanate. Although it has not been confirmed by other sources than the author of this article, experiments show that even if there is no precipitation of lead(II) thiocyanate in the solution,

crystals A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...

of the salt may form.

Synthesis

Lead(II) thiocyanate can be formed from the acidification of

lead(II) nitrate Lead(II) nitrate is an inorganic compound with the chemical formula Pb( NO3)2. It commonly occurs as a colourless crystal or white powder and, unlike most other lead(II) salts, is soluble in water. Known since the Middle Ages by the name plumbu ...

, Pb(NO₃)₂, with nitric acid, HNO₃, in the presence of

thiocyanic acid Thiocyanic acid is a chemical compound with the formula HSCN and structure , which exists as a tautomer with isothiocyanic acid (HNCS). The iso- form tends to dominate with the material being about 95% isothiocyanic acid in the vapor phase. : I ...

, HSCN. It may also be made by reacting

lead(II) acetate Lead(II) acetate (Pb(CH3COO)2), also known as lead acetate, lead diacetate, plumbous acetate, sugar of lead, lead sugar, salt of Saturn, or Goulard's powder, is a white crystalline chemical compound with a slightly sweet taste. Like many other l ...

(Pb(CH₃COO)₂) solved in water with either

potassium thiocyanate Potassium thiocyanate is the chemical compound with the molecular formula KSCN. It is an important salt of the thiocyanate anion, one of the pseudohalides. The compound has a low melting point relative to most other inorganic salts. Use in chem ...

(KSCN) or

ammonium thiocyanate Ammonium thiocyanate is an inorganic compound with the formula NH4SCN. It is the salt of the ammonium cation and the thiocyanate anion. Uses Ammonium thiocyanate is used in the manufacture of herbicides, thiourea, and transparent artificial resin ...

(NH₄SCN), thus causing a white

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

of solid lead(II)

thiocyanate Thiocyanate (also known as rhodanide) is the anion . It is the conjugate base of thiocyanic acid. Common derivatives include the colourless salts potassium thiocyanate and sodium thiocyanate. Mercury(II) thiocyanate was formerly used in pyr ...

according to the ion reaction: :Pb²⁺(aq) + 2SCN⁻(aq) → Pb(SCN)₂(s)

Reactivity

When exposed to UV or visible light lead thiocyanate will turn yellow due to the presence of sulfur. It is violently oxidized by nitric acid and will releases hydrogen cyanide gas after contact with acid, which is toxic. High amounts of heat such as that produces in a house fire will releases sulfur dioxide gas, also toxic. Like other metal cyanides, Lead thiocyanate explodes on heating when mixed with

sodium nitrite Sodium nitrite is an inorganic compound with the chemical formula NaNO2. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. From an industrial perspective, it is the most important nitrite ...

Health hazards

Skin and eye irritant, can induce lead poisoning by ingestion or inhalation. Symptoms include gastrointestinal disorders, irritation of digestive tract, leg cramps, muscle weakness, paresthesia. High doses can result in coma or death. Symptoms present in 1 to 2 days.

Lead poisoning

Most lead(II) salts have a sweet taste making them a hazard for continued consumption small children. While lead thiocyanate was likely not used in paints due to its

light sensitivity Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicity ...

, many lead based paints have been used pre-1970s. The paint has a tendency to peel and fall off making it likely to expose small children and pets. Since lead poisoning occurs with the binding of lead(II) to biological systems, research has been done to find ligands that more preferentially bind to lead(II) than other biological targets in an effort to combat the effects of lead poisoning.

Uses

Lead thiocyanate is used in explosives, specifically an ingredient in primers for small-arms cartridges, safety matches, and to reverse aniline black

dyeing Dyeing is the application of dyes or pigments on textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness. Dyeing is normally done in a special solution containing dyes and particular c ...

(Gideon). It can also be used as a precursor for preparing

perovskite solar cell A perovskite solar cell (PSC) is a type of solar cell that includes a perovskite-structured compound, most commonly a hybrid organic–inorganic lead or tin halide-based material as the light-harvesting active layer. Perovskite materials, such a ...

References

External links

Source for other names and health hazards
{{Lead compounds Thiocyanates Lead(II) compounds