Sodium cyanate
{{chembox
| verifiedrevid =
| Name = Sodium cyanate
| ImageFile = NaOCN explicitC.svg
| ImageSize =
| ImageName =
| ImageFile1 =
| ImageName1 =
| IUPACName =
| OtherNames =
|Section1={{Chembox Identifiers
| CASNo = 917-61-3
| CASNo_Ref = {{cascite|correct|CAS}}
| Beilstein = 3655041
| ChEBI = 38906
| ChEMBL = 1644696
| ChemSpiderID = 12922
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 8UFS3JRV8P
| PubChem = 517096
| EINECS = 213-030-6
| RTECS =
| UNNumber =
| InChI = 1S/CHNO.Na/c2-1-3;/h3H;/q;+1/p-1
| InChIKey = ZVCDLGYNFYZZOK-UHFFFAOYSA-M
| SMILES = C(#N)[O-].[Na+]
| MeSHName = C009281
}}
|Section2={{Chembox Properties
| Formula = NaOCN
| MolarMass = 65.01 g/mol
| Appearance = white crystalline solid
| Odor = odorless
| Density = 1.893 g/cm3
| MeltingPtC = 550
| Solubility = 11.6 g/100 mL (25 °C)
| SolubleOther = ethanol: 0.22 g/100 mL (0 °C)
dimethylformamide: 0.05 g/100 mL (25 °C)
slightly soluble in ammonia, benzene
insoluble in diethyl ether
}}
|Section3={{Chembox Structure
| CrystalStruct = body centered rhombohedral
}}
|Section4={{Chembox Thermochemistry
| DeltaHf = −400 kJ/mol
| DeltaGf =
| Entropy = 119.2 J/mol K
| HeatCapacity = 86.6 J/mol K
}}
|Section7={{Chembox Hazards
| ExternalSDS =
| GHSPictograms = {{GHS07}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|302|412}}
| PPhrases = {{P-phrases|264|270|273|301+312|330|501}}
| NFPA-H =
| NFPA-F =
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| NFPA-S =
| FlashPt =
| LD50 = 1500 mg/kg (rat, oral)
}}
}}
Sodium cyanate is the inorganic compound with the formula NaOCN. A white solid, it is the sodium salt of the cyanate anion.
Structure
The anion is described by two resonance structures:
{{chem2|N\tC\sO- and -N\dC\dO}}
The salt adopts a body centered rhombohedral crystal lattice structure (trigonal crystal system) at room temperature.Waddington, T.C. "Journal of the Chemical Society (Resumed)." 499. Lattice Parameters and Infrared Spectra of Some Inorganic Cyanates - (RSC Publishing). N.p., n.d. Web. 09 Nov. 2014.
Preparation
Sodium cyanate is prepared industrially by the reaction of urea with sodium carbonate at elevated temperature.
:2OC(NH2)2 + Na2CO3 → 2Na(NCO) + CO2 + 2NH3 + H2O
Sodium allophanate is observed as an intermediate:{{cite book |doi=10.1002/14356007.a08_157.pub2 |chapter=Cyanates, Inorganic Salts |title=Ullmann's Encyclopedia of Industrial Chemistry |year=2006 |last1=Schalke |first1=Peter M. |isbn=3527306730 }}
:{{chem2|H2NC(O)NHCO2Na -> NaOCN + NH3 + CO2}}
It can also be prepared in the laboratory by oxidation of a cyanide in aqueous solution by a mild oxidizing agent such as lead oxide.{{Greenwood&Earnshaw2nd|page=324}}
Uses and reactions
The main use of sodium cyanate is for steel hardening.
Sodium cyanate is used to produce cyanic acid, often in situ:
:{{chem2|NaOCN + HCl -> HOCN + NaCl}}
This approach is exploited for condensation with amines to give unsymmetrical ureas:
:{{chem2|HOCN + RNH2 -> RNHC(O)NH2}}
Such urea derivatives have a range of biological activity.{{cite journal|last1=Vinogradova|first1=Ekaterina V.|last2=Fors|first2=Brett P.|last3=Buchwald|first3=Stephen L.|title=Palladium-Catalyzed Cross-Coupling of Aryl Chlorides and Triflates with Sodium Cyanate: A Practical Synthesis of Unsymmetrical Ureas|journal=Journal of the American Chemical Society|date=11 July 2012|volume=134|issue=27|pages=11132–11135|doi=10.1021/ja305212v|pmc=3472423|pmid=22716197}}
See also
References
{{Reflist}}
{{Sodium compounds}}
{{Cyanates}}
{{inorganic-compound-stub}}