In aqueous solution it gives a red colour with ferric chloride.
The aqueous solution is turned bluish black by ferrous sulphate containing a ferric salt.
It is obtained by the oxidation of orthophenylene diamine with ferric chloride; when a mixture of para-aminodimethylaniline and meta-toluylenediamine is oxidized in the cold, toluylene blue, an indamine, being formed as an intermediate product and passing into the red when boiled; and also by the oxidation of dimethylparaphenylene diamine with metatoluylene diamine.
PHARMACOSIDERITE, a mineral species consisting of hydrated basic ferric arsenate, 2FeAs04 Fe(OH)3.5H20.
With ferric chloride it gives a violet coloration, and with bromine water a white precipitate of tribromphenol.
Ferric thiocyanate has been suggested, and sulphur is said to have been detected in the mineral.
It is frequently used as a reducing agent: in acid solutions it reduces ferric to ferrous salts, arsenates to arsenites, permanganates to manganous salts, &c., whilst in alkaline solution it converts many organic nitro compounds into the corresponding amino derivatives.
They form many double salts and give a dark violet coloration with ferric chloride solution, this colour, however, gradually disappearing on standing, sulphur being precipitated.
Soc., 1902, 81, p. I) showed that this can be almost entirely avoided by replacing the manganese oxide by hydrated ferric oxide, the reaction proceeding according to the equation: 2Fe(OH) 3 3S0 2 = FeS 2 0 6 FeS0 3 3H 2 0.
He points out that the available oxygen in the oxides may react either as SO 2 + H 2 O ?-- O = H 2 SO 4 or as 2S0 2 -IH20 + 0 = H 2 S 2 0 6; and that in the case of ferric oxide 96% of the theoretical yield of dithionate is obtained, whilst manganese oxide only gives about 75%.
In the van Ruymbeke process the spent lyes are allowed to settle, and then treated with "persulphate of iron," the exact composition of which is a trade secret, but it is possibly a mixture of ferric and ferrous sulphates.
Ferric hydrate, iron soaps and all insoluble impurities are precipitated.
It may be regarded as a ferroso-ferric oxide, FeO.Fe 2 O 3, or as iron ferrate, Fe"Fe 2 '0 4.
For example, at first he represented ferrous and ferric oxides by the formulae Fe02, Fe03, and by the analogy of zinc and other basic oxides he regarded these substances as constituted similarly to Fe02, and the acidic oxides alumina and chromium oxide as similar to FeO 3.
For example, when a solution of a ferric salt is added to a solution of potassium thiocyanate, a deep red coloration is produced, owing to the formation of ferric thiocyanate.
Theoretically the reaction takes place in the case of ferric nitrate in the manner represented by the equation Fe(NOs) 3 + 3KCNS = Fe(CNS) 3 + 3KNOs; Ferric nitrate.
But it is found that even when more than sixty times the amount of potassium thiocyanate required by this equation is added, a portion of the ferric nitrate still remains unconverted, doubtless owing to the occurrence of the reverse change Fe (CNS) 3 +3KNOs =Fe(N03) 3+3KCNS.
If the substance does not melt but changes colour, we may have present: zinc oxide - from white to yellow, becoming white on cooling; stannic oxide - white to yellowish brown, dirty white on cooling; lead oxide - from white or yellowish-red to brownish-red, yellow on cooling; bismuth oxide - from white or pale yellow to orange-yellow or reddish-brown, pale yellow on cooling; manganese oxide - from white or yellowish white to dark brown, remaining dark brown on cooling (if it changes on cooling to a bright reddishbrown, it indicates cadmium oxide); copper oxide - from bright blue or green to black; ferrous oxide - from greyish-white to black; ferric oxide - from brownish-red to black, brownish-red on cooling; potassium chromate - yellow to dark orange, fusing at a red heat.
If silica be present, it gives the iron bead when heated with a little ferric oxide; if tin is present there is no change.
If phosphoric acid is absent, aluminium, chromium and ferric hydrates are precipitated.
If, however, phosphoric acid is present in the original substance,we may here obtain a precipitate of the phosphates of the remaining metals, together with aluminium, chromium and ferric hydrates.
In this case, the precipitate is dissolved in as little as possible hydrochloric acid and boiled with ammonium acetate, acetic acid and ferric chloride.
The precipitate formed by sulphuretted hydrogen may contain the black mercuric, lead, and copper sulphides, dark-brown bismuth sulphide, yellow cadmium and arsenious sulphides, orange-red antimony sulphide, brown stannous sulphide, dull-yellow stannic sulphide, and whitish sulphur, the last resulting from the oxidation of sulphuretted hydrogen by ferric salts, chromates, &c. Warming with ammonium sulphide dissolves out the arsenic, antimony and tin salts, which are reprecipitated by the addition of hydrochloric acid to the ammonium sulphide solution.
The next group precipitate may contain the white gelatinous aluminium hydroxide, the greenish chromium hydroxide, reddish ferric hydroxide, and possibly zinc and manganese hydroxides.
In the second group, we may notice the application of litmus, methyl orange or phenolphthalein in alkalimetry, when the acid or alkaline character of the solution commands the colour which it exhibits; starch paste, which forms a blue compound with free iodine in iodometry; potassium chromate, which forms red silver chromate after all the hydrochloric acid is precipitated in solutions of chlorides; and in the estimation of ferric compounds by potassium bichromate, the indicator, potassium ferricyanide, is placed in drops on a porcelain plate, and the end of the reaction is shown by the absence of a blue coloration when a drop of the test solution is brought into contact with it.
The substance is heated with metallic sodium or potassium (in excess if sulphur be present) to redness, the residue treated with water, filtered, and ferrous sulphate, ferric chloride and hydrochloric acid added.
The same decomposition may be effected by igniting with iron, ferric oxide and sodium carbonate (E.
Ferric chloride colours its aqueous solution violet.
In a purer condition it may be obtained by the action of sulphuric acid on a mixture of potassium nitrate and ferrous sulphate, or of hydrochloric acid on a mixture of potassium nitrate and ferric chloride.
They are silicates, usually orthosilicates, of aluminium together with alkalis (potassium, sodium, lithium, rarely rubidium and caesium), basic hydrogen, and, in some species magnesium, ferrous and ferric iron, rarely chromium, manganese and barium.
9474 (1892)] passes the gas (after freeing it from ammonia) through a solution of potassium carbonate containing ferric oxide or ferrous carbonate (actually ferrous sulphate and potassium carbonate) in suspension; the sulphuretted hydrogen in the gas probably converts the iron salts into ferrous sulphide which then, in the presence of the hydrocyanic acid in the gas, and the alkaline carbonate, forms the ferrocyanide, thus: FeS+6HCN+ 2K 2 CO 3 = K 4 Fe(NC) 6 + H 2 S + 2CO 2 + 2H 2 0.
A large quantity of the salt is now prepared from the "spent oxide" of the gas works, the cyanogen compounds formed in the manufacture of the gas combining with the ferric oxide in the purifiers to form insoluble iron ferrocyanides.
Prussian blue, Fe 7 (NC) 18 or Fe4[Fe(NC)6]3, ferric ferrocyanide, was discovered in 1710 by a German manufacturer named Diesbach, who obtained it by the action of fused alkali and iron salts on nitrogenous organic matter (e.g.
The grey precipitate first formed is allowed to stand for some hours, well washed, and then oxidised by a warm solution of ferric chloride: 6K 2 Fe[Fe(NC) 6] + 30 = Fe7(NC)18 + 3K 4 Fe(NC) 6 + Fe203.
Ferrous and ferric acetates are used as mordants; normal lead acetate is known in commerce as sugar of lead; basic copper acetates are known as verdigris.
Quinhydrone, C 6 H40 2 -C 6 H 4 (OH) 2, is formed by the direct union of quinone and hydroquinone or by careful oxidation of hydroquinone with ferric chloride solution.
Other precipitants of phosphoric acid or its salts in solution are: ammonium molybdate in nitric acid, which gives on heating a canary-yellow precipitate of ammonium phosphomolybdate, 12[M00 3] (NH 4) 3 PO 4, insoluble in acids but readily soluble in ammonia; magnesium chloride, ammonium chloride and ammonia, which give on standing in a warm place a white crystalline precipitate of magnesium ammonium phosphate, Mg(NH 4)PO 4.6H 2 0, which is soluble in acids but highly insoluble in ammonia solutions, and on heating to redness gives magnesium pyrophosphate, Mg 2 P 2 0 7; uranic nitrate and ferric chloride, which give a yellowish-white precipitate, soluble in hydrochloric acid and ammonia, but insoluble in acetic acid; mercurous nitrate which gives a white precipitate, soluble in nitric acid, and bismuth nitrate which gives a white precipitate, insoluble in nitric acid.
The blue colouring substance is ferrous sulphide, the upper reddish layer contains more ferric oxide, which the predominance of decomposing organic matter in the substance of the mud reduces to ferrous oxide and subsequently by further action to sulphide.
Red mud may be classed as a variety of blue mud, from which it differs on account of the larger proportion of ochreous substance and the absence of sufficient organic matter to reduce the whole of the ferric oxide.
Oxidizing agents (ferric chloride, &c.) give a blue precipitate with solutions of its salts.
Weith, Ber., 1880, 13, 1300); or in the form of its acetyl derivative by heating /3-naphthol with ammonium acetate to 270-280° C. It forms odourless, colourless plates which melt at 111-112° C. It gives no colour with ferric chloride.