Fulminate ion

Fulminate ion >(C=N-0)- 109 Linear another form of AgCNO has r(C-N) 112pm... 

Similar differences are found for organic azides (e.g. MeN3). In ionic azides (p. 417) the N3 ion is both linear and symmetrical (both N-N distances being 116 pm) as befits a 16-electron species isoelectronic with CO2 (cf. also the cyanamide ion NCN, the cyanate ion NCO, the fulminate ion CNO and the nitronium ion N02 ). 

The fulminate ion, CNO-, probably has a structure intermediate between C N O and C N 6 for since these two bond types have the same bond angles and term symbols ( 2), they can form intermediate structures lying anywhere between the two extremes. Which extreme is the more closely approached could be determined from a study of the bond angles in un-ionized fulminate molecules, such as AgCNO or ONCHgCNO, for the first structure would lead to an angle of 125° between the CNO axis and the metal-carbon bond, the second to an angle of 180°. 

Both structures II and III have an arrangement of atoms that places a positive formal charge on atoms that are higher in electronegativity than carbon. Consequently, the most stable arrangement of atoms is as shown in structure I. Some compounds containing the ion having structure III (the fulminate ion) are known, but they are much less stable than the cyanates (structure I). In fact, mercury fulminate has been used as a detonator. 

As shown in the introduction, the DNM anion can be regarded as a resonance stabilized, nonlinear planar pseudohalide, which forms an insoluble, highly explosive brownish silver salt upon addition of silver nitrate to an aqueous solution of 7. The DNM anion is related to the linear fulminate ion (CNO ) and can formally be regarded as the addition product of NO to fulminic acid (HCNO). Starting from CH4, NO containing nonlinear pseudohalides can be derived by successive substitution of H by NO, e.g. H3C(NO)/H2C(NO), H2C(N0)2/HC(N0)2 and HC(NO)3/C(NO)3, whereas the linear pseudohalide CNO is formally formed by replacing three H atoms by one NO unit and deprotonation. 

When iso is placed in parentheses, e.g. (isojcyanate, the point of attachment of the pseudohalide to the metal(s) is not known. bThe isoelectronic fulminate ion—ONC will be considered in Chapter 12.1. 

Beck and coworkers211 have reviewed transition metal complexes of the fulminate ion, CNO, which bonds to the metal via the carbon atom. Fulminate complexes are, in general, similar to those with CN ligands. An extensive series of stable, non-explosive fulminates has been examined, including [Ir(CNO)6](AsPh4)3. [Ir(CNO)6]3- was prepared from hydrated iridium(III) chloride and Hg(CNO)2, and characterized by IR spectroscopy.21"1... 

Fuhninic acid, C=N H C=N-OH, is a divalent carbon derivative hke carbon monoxide it is formally an oxime of carbon monoxide. Free fuhninic acid is unstable, but the explosive mercury salt, which is used as a detonator, is obtained by treatment of elemental mercury with a mixture of ethanol and lutric acid. The fulminate ion, C=N-0, like carbon monoxide and cyanide ion, functions as a strong-field... 

Oxidation of the cyanide ion produces the stable cyanate ion, OCN-. The fulminate ion, CNO-, on the other hand, is very unstable. Fulminate salts explode when struck Hg(CNO)2 is used in blasting caps. Write the Lewis structures and assign formal charges for the cyanate and fulminate ions. Why is the fulminate ion so unstable (C is" the central atom in OCN- and N is the central atom in CNO-.)... 

Nitrous acid, sodium nitrite, potassium nitrite hyponitrous acid and the hypo-nitrites hydrogen cyanide, potassium cyanide, cyanogen the cyanate ion, fulminate ion, azide ion, and thiocyanate ion. 

CNO The isomeric fulminate ion, CNO (Figure 3-5), can be drawn with three similar structures, but the resulting formal charges are unlikely. Because the order of electronegativities is C < N < O, none of these are plausible structures and the ion is predicted to be unstable. The only common fulminate salts are of mercury and silver both are explosive. Fulminic acid is linear HCNO in the vapor phase, consistent with structure C, and coordination complexes of CNO with many transition metal ions are known with MCNO structures. ... 

All the metal fulminates are expected to be unstable because of the extreme charge asymmetry of the fulminate ion. The fulminates decompose with extensive polymerization (86) which is understandable in... 

The fulminate ion, [CNO] , is an isomer of the cyanate ion. Fulminate salts can be reduced to cyanides but cannot be prepared by oxidation of them. The free acid readily polymerizes but is stable for short periods in Et20 at low temperature. Metal fulminates are highly explosive mercury(II) fulminate may be prepared by reaction 13.82 and is a dangerous detonator. 

In contrast to the cyanate ion (NCO ), which is stable and found in many compounds, the fulminate ion (CNO ), with its different atom sequence, is unstable and forms compounds with heavy metal ions, such as Ag and Hg " ", that are explosive. Like the cyanate ion, the fulminate ion has three resonance structures. Which is the most important contributor to the resonance hybrid Suggest a reason for the instability of fulminate. 

The repulsion energy was found to be greater in the fulminate ion by 3e /1.16, or 3624 kJ/mole. Since the atomic kernels are shielded by the valence electrons, the repulsive energy is probably 10% of the above value. The difference in the enthalpy of formation of AgCNO and AgNCO is 270 kJ/mole [3], which is roughly 10% of the calculated number. 

The fulminate ion, CNO", where N is the central atom, is highly unstable. In feet, metal fulminates are explosive and have been used in percussion caps. Sketch all the possible resonance structures for the fulminate ion, determine the FCs on each atom in every canonical structure, and discuss why you think the fulminate ion is so unstable. 

The visible and ultraviolet spectra of various fulminate complexes have been determined in order to estimate the ligand field suength of the fulminate ion CNO". The absorption bands of the diamagnetic (1) octahedral fulminate complexes [FefCNO) ], [Fe(CN) CNO], [Co(CNO) ] have been assigned from the wavenumbers of the two ligand field bands ( -> Tig and... 

In contrast to the cyanate ion (NCO ), which is stable and found in many compounds, the fulminate ion (CNO ), with its different atom sequence, is unstable and forms compounds with... 

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