Cyanate is an

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

with the

structural formula The structural formula of a chemical compound is a graphic representation of the molecular structure (determined by structural chemistry methods), showing how the atoms are possibly arranged in the real three-dimensional space. The chemical bond ...

, usually written . It also refers to any salt containing it, such as ammonium cyanate. It is an

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Is ...

of the much less stable fulminate anion .William R. Martin and David W. Ball (2019): "Small organic fulminates as high energy materials. Fulminates of acetylene, ethylene, and allene". ''Journal of Energetic Materials'', volume 31, issue 7, pages 70-79. A cyanate ester is an organic compound containing the cyanate group. The cyanate ion is an ambidentate ligand, forming complexes with a metal ion in which either the nitrogen or oxygen atom may be the electron-pair donor. It can also act as a

bridging ligand In coordination chemistry, a bridging ligand is a ligand that connects two or more atoms, usually metal ions. The ligand may be atomic or polyatomic. Virtually all complex organic compounds can serve as bridging ligands, so the term is usually ...

Cyanate ion

The three atoms in a cyanate ion lie on a straight line, giving the ion a linear structure. The electronic structure is described most simply as : :Ö̤−C≡N: with a single C−O bond and a triple C≡N bond. The

infrared spectrum Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

of a cyanate salt has a band at ca. 2096 cm⁻¹; such a high frequency is characteristic of a

triple bond A triple bond in chemistry is a chemical bond between two atoms involving six bonding electrons instead of the usual two in a covalent single bond. Triple bonds are stronger than the equivalent single bonds or double bonds, with a bond order o ...

. The cyanate ion is a

Lewis base A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any sp ...

. Both the oxygen and nitrogen atoms carry a

lone pair In chemistry, a lone pair refers to a pair of valence electrons that are not shared with another atom in a covalent bondIUPAC '' Gold Book'' definition''lone (electron) pair''/ref> and is sometimes called an unshared pair or non-bonding pair. L ...

of electrons and either one or the other, or both can be donated to

Lewis acid A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any sp ...

acceptors. It can be described as an ambidentate ligand.

Cyanate salts

Sodium cyanate is isostructural with sodium fulminate, confirming the linear structure of the cyanate ion. It is made industrially by heating a mixture of

sodium carbonate Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...

and

urea Urea, also known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important ...

. :Na2CO3 + 2 OC(NH2)2 -> 2 NaNCO + CO2 + 2 NH3 + H2O A similar reaction is used to make potassium cyanate. Cyanates are produced when

cyanide Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...

s are oxidized. Use of this fact is made in cyanide decontamination processes where oxidants such as

permanganate A permanganate () is a chemical compound containing the manganate(VII) ion, , the conjugate base of permanganic acid. Because the manganese atom is in the +7 oxidation state, the permanganate(VII) ion is a strong oxidizing agent. The ion is a ...

and

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3 ...

are used to convert toxic cyanide to safer cyanate.

Complexes with the cyanate ion

Cyanate is an ambidentate ligand which can donate the pair of electrons on the nitrogen atom or the oxygen atom, or both. Structurally the isomers can be distinguished by the geometry of the complex. In ''N''-bonded cyanate complexes the M−NCO unit sometimes has a linear structure, but with ''O''-bonded cyanate the M−O−C unit is bent. Thus, the silver cyanato complex, g(NCO)₂sup>−, has a linear structure as shown by

X-ray crystallography X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...

. (clic
here
However, the crystal structure of silver cyanate shows zigzag chains of nitrogen atoms and silver atoms. There also exists a structure NCO / \ Ni Ni \ / OCN in which the Ni-N-C group is bent.

Infrared spectroscopy Infrared spectroscopy (IR spectroscopy or vibrational spectroscopy) is the measurement of the interaction of infrared radiation with matter by absorption, emission, or reflection. It is used to study and identify chemical substances or functi ...

has been used extensively to distinguish between isomers. Many complexes of divalent metals are ''N''-bonded. ''O''-bonding has been suggested for complexes of the type (OCN)₆sup>''n''−, M = Mo(III), Re(IV) and Re(V). The yellow complex Rh(PPh₃)₃(NCO) and orange complex Rh(PPh₃)₃(OCN) are linkage isomers and show differences in their infrared spectra which can be used for diagnosis (PPh₃ stands for

triphenylphosphine Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to P Ph3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. PPh3 exists ...

).Nakamoto, Part B, pp 121–123. The cyanate ion can bridge between two metal atoms by using both its donor atoms. For example, this structure is found in the compound en)₂.html"_;"title="ethylene_diamine.html"_;"title="i₂(NCO)₂(ethylene_diamine">en)₂">ethylene_diamine.html"_;"title="i₂(NCO)₂(ethylene_diamine">en)₂nowiki>[tetraphenylborate.html" ;"title="ethylene_diamine">en)₂.html" ;"title="ethylene_diamine.html" ;"title="i₂(NCO)₂(ethylene diamine">en)₂">ethylene_diamine.html" ;"title="i₂(NCO)₂(ethylene diamine">en)₂nowiki>[tetraphenylborate">BPh₄]₂. In this compound both the Ni−N−C unit and Ni−O−C unit are bent, even though in the first case donation is through the nitrogen atom.Greenwood, Table 8.9

Cyanate in organic compounds

The functional group is known as a nitrile oxide.

Organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

s that contain the

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the r ...

−N=C=O are known as isocyanates. It is conventional in

organic chemistry Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J ...

to write isocyanates with two double bonds, which accords with a simplistic

valence bond theory In chemistry, valence bond (VB) theory is one of the two basic theories, along with molecular orbital (MO) theory, that were developed to use the methods of quantum mechanics to explain chemical bonding. It focuses on how the atomic orbitals of ...

of the bonding. In nucleophilic substitution reactions cyanate usually forms an isocyanate. Isocyanates are widely used in the manufacture of polyurethane products and

pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and ...

s; methyl isocyanate, used to make pesticides, was a major factor in the

Bhopal disaster The Bhopal disaster, also referred to as the Bhopal gas tragedy, was a chemical accident on the night of 2–3 December 1984 at the Union Carbide India Limited (UCIL) pesticide plant in Bhopal, Madhya Pradesh, India. Considered the world's ...

. Compounds that contain the group −O−C≡N, are known as a cyanates, or cyanate esters.

Aryl In organic chemistry, an aryl is any functional group or substituent derived from an aromatic ring, usually an aromatic hydrocarbon, such as phenyl and naphthyl. "Aryl" is used for the sake of abbreviation or generalization, and "Ar" is used ...

cyanates such are phenyl cyanate, C₆H₅OCN, can be formed by a reaction of

phenol Phenol (also called carbolic acid) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile. The molecule consists of a phenyl group () bonded to a hydroxy group (). Mildly acidic, it r ...

with cyanogen chloride, ClCN, in the presence of a base.

References

External links

Material Safety Data Sheet for potassium cyanate

Bibliography

* * * * {{Functional group Oxyanions Functional groups