_thiocyanate.svg) | |
| Names | |
|---|---|
| IUPAC name Lead(II) thiocyanate | |
| Systematic IUPAC name Lead(II) thiocyanate | |
| Other names Lead dithiocyanate, lead isothiocyanate, lead sulfocyanate, lead thiocyanate, lead thiocyanate (Pb(SCN) 2), lead(II) thiocyanate, lead(II) thiocyanate (Pb(NCS) 2), thiocyanic acid, lead(2+) salt | |
| Identifiers | |
| |
3D model (JSmol) | |
| ChemSpider |
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| ECHA InfoCard | 100.008.887 |
| EC Number |
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| UNII | |
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| Properties | |
| Pb(SCN)2 | |
| Molar mass | 323.3648 g/mol |
| Appearance | white or light yellow powder |
| Odor | odorless |
| Density | 3.82 g/cm3 |
| Melting point | 190 °C (374 °F; 463 K) |
| 0.553 g/100 mL | |
| Solubility | soluble innitric acid |
| −82.0·10−6 cm3/mol | |
| Hazards | |
| GHS labelling: | |
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| Danger | |
| H302,H312,H332,H360,H373,H410 | |
| P201,P202,P260,P261,P264,P270,P271,P273,P280,P281,P301+P312,P302+P352,P304+P312,P304+P340,P308+P313,P312,P314,P322,P330,P363,P391,P405,P501 | |
| NFPA 704 (fire diamond) | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Lead(II) thiocyanate is acompound, more precisely asalt, with theformula 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.[1] Lead thiocyanate can causelead poisoning if ingested and can adversely react with many substances. It has use in small explosives, matches, and dyeing.
Lead(II) thiocyanate is reasonably soluble atroom temperature, thus it may be difficult to identify in a solution with lowconcentration of lead(II) thiocyanate. Although it has not been confirmed by other sources than the author of this[which?] article, experiments show that even if there is no precipitation of lead(II) thiocyanate in the solution,crystals of the salt may form.
Lead(II) thiocyanate can be formed from the acidification oflead(II) nitrate, Pb(NO3)2, with nitric acid, HNO3, in the presence ofthiocyanic acid, HSCN. It may also be made by reactinglead(II) acetate (Pb(CH3COO)2) solved in water with eitherpotassium thiocyanate (KSCN) orammonium thiocyanate (NH4SCN), thus causing a whiteprecipitation of solid lead(II)thiocyanate according to the ion reaction:
According toX-ray crystallography, the anhydrous salt is acoordination polymer. The Pb2+ ions are each bonded to eightthiocyanate anions, with four Pb-S and four Pb-N bonds. The motif is reminiscent of thefluorite structure.[2]Strontium thiocyanate,calcium thiocyanate, andbarium thiocyanate adopt the same structure.
When exposed to UV or visible light, lead thiocyanate will turn yellow due to the presence of sulfur.[citation needed] It is violently oxidized by nitric acid[3] and will release highly toxichydrogen cyanide gas on contact with acid. At high temperatures[quantify] it releasessulfur dioxide gas. Like other metal cyanides, it explodes on heating when mixed withsodium nitrate.[citation needed]
Skin and eye irritant, can inducelead 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.
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 itslight sensitivity, manylead 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.[4]
Lead thiocyanate is used in explosives, specifically an ingredient in primers for small-arms cartridges, safety matches, and to reverse aniline blackdyeing (Gideon). It can also be used as a precursor for preparingperovskite solar cells.[5]
