PROFILPELAJAR.COM

Lead(II) thiocyanate
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
CAS Number	592-87-0 ;
3D model (JSmol)	Interactive image;
ChemSpider	11127 ;
ECHA InfoCard	100.008.887
EC Number	209-774-6;
PubChem CID	11616;
UNII	7977FZ765Q ;
CompTox Dashboard (EPA)	DTXSID90890513 ;
	InChI InChI=1S/2CHNS.Pb/c22-1-3;/h23H;/q;;+2/p-2 Key: VRNINGUKUJWZTH-UHFFFAOYSA-L ;
	SMILES C(#N)[S-].C(#N)[S-].[Pb+2];
Properties
Chemical formula	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)
Solubility in water	0.553 g/100 mL
Solubility	soluble in nitric acid
Magnetic susceptibility (χ)	−82.0·10−6 cm3/mol
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H312, H332, H360, H373, H410
Precautionary statements	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)	1 1 1
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). compounds:11&page2=Lead%28II%29+thiocyanate verify (what is ?) Infobox references

Lead(II) thiocyanate is a compound, more precisely a salt, 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.^[1] 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 in both compound( top) and salt (bottom) forms.

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

Synthesis

Lead(II) thiocyanate can be formed from the acidification of lead(II) nitrate, Pb(NO₃)₂, with nitric acid, HNO₃, in the presence of thiocyanic acid, HSCN. It may also be made by reacting lead(II) acetate (Pb(CH₃COO)₂) solved in water with either potassium thiocyanate (KSCN) or ammonium thiocyanate (NH₄SCN), thus causing a white precipitation of solid lead(II) thiocyanate 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^[2] 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.

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, 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.^[3]

Uses

Lead thiocyanate is used in explosives, specifically an ingredient in primers for small-arms cartridges, safety matches, and to reverse aniline black dyeing (Gideon). It can also be used as a precursor for preparing perovskite solar cells.^[4]

References

^ Urbanski, Tadeusz (1967). Chemistry and Technology of Explosives. Pergamon Press. pp. Volume 3, 230.
^ Bretherick (1979). Handbook of Reactive Chemical Hazards. Butterworth-Heinemann. p. 121.
^ Platas-Iglesias, Carlos; Esteban-Gómez, David; Enríquez-Pérez, Teresa; Avecilla, Fernando; de Blas, Andrés; Rodríguez-Blas, Teresa (2005-04-04). "Lead(II) thiocyanate complexes with bibracchial lariat ethers: an X-ray and DFT study". Inorganic Chemistry. 44 (7): 2224–2233. doi:10.1021/ic048768y. ISSN 0020-1669. PMID 15792457.
^ Tai, Qidong; You, Peng; Sang, Hongqian; Liu, Zhike; Hu, Chenglong; Chan, Helen L. W.; Yan, Feng (2016-04-01). "Efficient and stable perovskite solar cells prepared in ambient air irrespective of the humidity". Nature Communications. 7: 11105. Bibcode:2016NatCo...711105T. doi:10.1038/ncomms11105. PMC 4821988. PMID 27033249.