Cobalt Azide

Cobalt Triazide (formerly call Cobalt Tri-nitride or Cobalt Azoimide) Co(N,)j, raw 142.99, N58.78% red-brn crysts (anhyd), mp det 148° (0.02 g in 5 sec) (Ref 5), hygroscopic and easily hydrolyzed (Ref 4). The basic cobalt azide, Co(OH)N, was first prepd in 1898 by Curtius Rissom (Ref 1). An aq soln of cobalt azide was studied by Dennis Isham (Ref 2). The anhyd salt, prepd by ihe action of cobaitous carbonate on hydrazoic acid, was prepd by Wohler (Ref 3) and by Wohler Si Martin MptKrvrl C nf nr hrt... 

Cobalt Azide Complexes — Curtius Rissom (Ref 1) found that potassium cobaltoazoimide,... 

Cobalt Azide Complexes — Curtius Rissom (Ref 1) found that potassium cobaltoazoimide, [KNj-CofNjl ], pptd when strong solns of the two azides were mixed. This compd appeared as bright-blue crysts (pink in soln) which expl at 225°, The ammonium analogue, [(NHJN,(CO(N,)J, was similar in appearance and props (Ref 1). 

Electron transfer oxidation of 4-methoxyphenol using wjeio-tetraphenylporphyrin as the electron acceptor brings about dehydrodimerization of the phenol to yield 5. The presence of the radical cation of the phenol has been detected by CIDNP techniques. The same product is obtained by irradiation of the tetraphenylporphyrin/benzoquinone/p-methoxyphenol system . Pyrimidinopteridine Af-oxide has been used as a sensitizer to effect the hydroxylation of phenols, also involving the radical cation of the phenol. Thus phenol can be converted to catechol and hydroquinone while cresol yields 4-methyl-catechol . Hydroquinone can itself be oxidized by the cobalt azide complex in aqueous... 

A basic product of the approximate composition (OH)Co(N3) is made by heating an aqueous cobalt azide solution to precipitate a violet solid. Dipositive cobalt forms a tetraazidocobaltate(II) complex, [Co (N3)4] ", in aqueous cobalt(II) salt solutions with a 15-fold sodium azide excess at pH 5 and may be... 

Cobalt azide Co(N3)2 shock crystallization and purification should be handled very carefully explodes on reactions with acids susceptible to react with heavy metal salts forming their azides Explodes on heating at 200°C (392°F) susceptible to... 

A drop of the test solution is placed on filter paper and spotted with a (hrop of a saturated water solution of sodium azide. The fleck is exposed to the vapors of a saturated aqueous solution of sulfurous acid. A yellow color appears which changes to blue on treatment with a drop of a 2 % acetic acid solution of a-tolidine Idn, Limit 0.5 y Co). The test is based on the fact that the oxidation of complex Co azide to complex cobalt azide is catalyzed by the autoxidation of sulfurous acid. The color reaction with o-tolidine is due to the action of the tervalent cobalt formed. Copper and iron ions interfere and should be previously removed or masked. The test can be carried out in the presence of as much as 200 times the amount of nickel. 

On adding an excess of sodium azide to neutral or slightly acid solutions of cobalt salts, a violet color appears which is due to complex cobalt -azide anions. In contact with air an oxidation to anionic azide-complexes of tervalent cobalt takes place, shown by a change of color from violet to yellow. This very slow autoxidation is enormously accelerated by sulfurous acid or sulfite ions. Probably the autoxidation of sulfite to sulfate induces the oxidation of the complex bounded cobalt. However, the color change violet yellow is not sufficiently sensitive to serve as a test for this induction effect and therefore, for sulfite. It is better to identify the tervalent cobalt through a color reaction with an acetic acid solution of o-tolidine (formation of a blue quinoidal oxidation product of the base). Compare page 209. 

Some other metallic azides, like cadmium azide, are extremely sensitive to mechanical stimuli. Nickel azide is extremely sensitive to friction it explodes by slight pressure or rubbing between metal and glass. Cobalt azide is even more sensitive than nickel azide. On the other hand, zinc azide detonates rally under strong impact [115]. 

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