Ammonium cyanate

Ammonium cyanate is an inorganic compound with the formula [NH₄]⁺[OCN]⁻. It is a colorless, solid salt.

Ammonium cyanate

Identifiers
CAS Number	22981-32-4
3D model (JSmol)	Interactive image
ChemSpider	2339431
PubChem CID	9793686
CompTox Dashboard (EPA)	DTXSID40177528
InChI InChI=1S/CHNO.H3N/c2-1-3;/h3H;1H3 Key: QYTOONVFPBUIJG-UHFFFAOYSA-N
SMILES C(#N)[O-].[NH4+]
Properties
Chemical formula	[NH4][OCN]
Molar mass	60.056 g·mol−1
Appearance	Colorless crystals
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Structure and reactions

The structure of this salt was verified by X-ray crystallography. The respective C–O and C–N distances are 1.174(8) and 1.192(7) Å, consistent with the O=C=N⁻ description. Ammonium cation [NH₄]⁺ forms hydrogen bonds with cyanate anion O=C=N⁻, but to N, not to O.^[1]

The compound is notable as the precursor in the Wöhler synthesis of urea, an organic compound, from inorganic reactants.^[2] This led to the discarding of the Vital force theory, suggested earlier by Berzelius.

NH+4 + OCN⁻ → (NH₂)₂CO^[3]

References

1. MacLean, Elizabeth J.; Harris, Kenneth D. M.; Kariuki, Benson M.; Kitchin, Simon J.; Tykwinski, Rik R.; Swainson, Ian P.; Dunitz; Jack D. (2003). "Ammonium cyanate shows N-H···N hydrogen bonding, not N-H···O". Journal of the American Chemical Society. 125 (47): 14449–14451. doi:10.1021/ja021156x. PMID 14624593.
2. Friedrich Wöhler (1828). "Ueber künstliche Bildung des Harnstoffs". Annalen der Physik und Chemie. 88 (2): 253–256. Bibcode:1828AnP....88..253W. doi:10.1002/andp.18280880206.
3. Shorter, J. (1978). "The conversion of ammonium cyanate into urea. A saga on Reaction mechanisms". Chemical Society Reviews. 7: 1–14. doi:10.1039/CS9780700001.