Cobaltinitrites

Dinitronaphthalene (Delta-dinitronaphtha-lenet 1,6-DNN). Crysts from acet ac, mp 166-67°, bp at 10mm 235°, 360° with decompn (Refs 2 31) CA Registry No 60746-5. It is prepd by the nitration of 2-nitronaphtha- ene with nitric ac/sulfuric ac in hot acet ac (Ref 21) by diazotization of 5-nitro-2-naphthyl-amine followed by treatment of the diazonium salt with Na cobaltinitrite, yield 40% (Ref 36) or by removal of the amino group from 1,6-dinitro-2-naphthylamine by diazotization followed by redn (Ref 17). The temp of expin is 492°(Refl7)... 

The earliest investigation of the exchange reaction between the aquated ions of Co(III) and Co(II) was carried out by Hoshowsky et al., using the isotopic method ( Co). When sulphate salts ( 10 M) were employed, complete exchange was observed between the two oxidation states of cobalt, in a time of less than two min. Two separation methods were employed (a) adsorption on an alumina column, and (b) precipitation of the Co(III) as the cobaltinitrite. 

Evaporation by heating a filtrate from precipitation of potassium cobaltinitrite caused it to turn purple and explode violently [1]. This was attributed to interaction of nitrite, nitrate, acetic acid and residual cobalt with formation of fulminic or methylnitrolic acids or their cobalt salts, all of which are explosive [2], Mixtures containing nitrates, nitrites and organic materials are potentially dangerous, especially in presence of acidic materials and heavy metals. A later publication confirms the suggestion of formation of nitro- or nitrito-cobaltate(III) [3],... 

The spectrum of sodium cobaltinitrite shown in Fig. 13 is also of type I with the maximum at 27 ev. The spectrum differs from the ammonia and ethylene diamine coordinated cobaltic compounds in yielding a pattern... 

To a little of the filtrate from the crystals, add a solution of a potassium salt, observing the instant precipitation of the insoluble potassium cobaltinitrite. An excess added to all of the mother liquors will give a preparation... 

To determine rubidium, the irradiated coal sample and added rubidium carrier are digested and the organic matter destroyed by heating with nitric and sulfuric acids, followed by nitric and perchloric acids. The rubidium is separated from the gross activity of the sample by precipitation with ferric hydroxide. The rubidium is then precipitated as the cobaltinitrite and finally as the chloroplatinate. The activity of the chloroplatinate caused by the 1.8 MeV /T particle of 18.7-day 86Rb is counted with a Geiger counter. 

Cobaltinitrite Diammonium sodium cobaltinitrite, (NH4)2NaCo(N02)6H20... 

Cobaltinitrite. Dipotassium sodium cobaltimtnte. K NaCotNO )6"H20, golden yellow precipitate, formed by reaction of sodium cobaltinitrite solution in acetic acid with soluble potassium salt solution Used in the detection of potassium. 

Cobalt Nitrite Complexes. When KNOz is added in excess to a soln of Co(NOa)2,acidified with AcOH, a yel ppt of potassium hexa-nitrocobaltiate (potassium cobaltinitrite),... 

K3 [Co(N02)6] fojrms. This compd is also known as Fischer s Salt or as a pigment Cobalt Yellow. Formation of above complex can serve as the basis of a volumetric detn of Co ion. When a sol K salt is added to sodium cobaltinitrite, Naj [Co(N02)6], a yel cryst ppt potassium-sodium cobaltinitrite K2Na[Co(N02)6], HzO is formed. This com-... 

Nitrobenzo[6]thiophene may be prepared by reaction of the 3,4-dinitro compound with alcoholic ammonium sulfide422-538 other workers have claimed that this method yields only traces of the desired product.84 It may also be prepared by deamination of 5-amino-4-nitrobenzo[6]thiophene,162,422 or by decomposition of 4-benzo[6]-thiophene diazonium cobaltinitrite with aqueous sodium nitrite in the presence of cuprous oxide and cupric sulfate.84 7-Nitrobenzo[6]-thiophene may be obtained by the latter method (15% yield) from the corresponding amine.84... 

More rarely use is made for the same purpose of other substances such as strontium and calcium chromates, lead oxychloride (Cassel yellow), lead protoxide, arsenic sulphide (orpiment), stannic sulphide (mosaic gold), potassium cobaltinitrite (cobalt yellow), etc. 

K and Cs form insoluble salts with anions such as phosphomolybdate, silicotungstate, and cobaltinitrite. 

Sodium rhodinitrite dissolves in 2 times its weight of water at 17° C., and in one part of boiling water. It is thus considerably more soluble than its potassium analogue. Its solution, however, does not give the reactions for rhodium, which suggests that it is a rhodinitrite, Na3Rh(N02)6, analogous to potassium cobaltinitrite. 

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