Ferric Sentence Examples

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.

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.

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.

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.

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.

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.

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.

It appears, therefore, that liquid oxygen is by far the most strongly paramagnetic liquid known, its susceptibility being more than four times greater than that of a saturated solution of ferric chloride.

It is volatile (para-oxybenzaldehyde is not) and gives a violet coloration with ferric chloride.

This solution is allowed to stand for some time (in order that any calcium sulphate and basic ferric sulphate may separate), and is then evaporated until ferrous sulphate crystallizes on cooling; it is then drawn off and evaporated until it attains a specific gravity of 1.40.

Berzelius about 1823 found that the yellow oxide, when treated with excess of sulphuric acid, gave a sulphate not unlike the ferric salt.

Ferric oxide gives a yellow colour, but requires the presence of an oxidizing agent to prevent reduction to the ferrous state.

By converting ferrous into ferric oxide the green tint is changed to yellow, which is less noticeable.

In the case of iron, ferric sulphate, Fe2(S04) 3, is produced; tin yields a somewhat indefinite sulphate of its oxide Sn02.

Hydriodic acid reduces it to hexamethylene" (cyclo-hexane or hexa-hydro-benzene); chlorine and bromine form substitution and addition products, but the action is slow unless some carrier such as iodine, molybdenum chloride or ferric chloride for chlorine, and aluminium bromide for bromine, be present.

Both are easily removed by passing chlorine through the cold solution, to produce ferric and manganic salt, and then digesting the liquid with a washed precipitate of basic carbonate, produced from a small portion of the solution by means of sodium carbonate.

Titanic oxide separates out as a white hydrate, which, however, is generally contaminated with ferric hydrate and often with tin oxide.

Potassium ferric oxalate, FeK3(C204)3, is used in the preparation of platinotypes, owing to the fact that its solution is rapidly decomposed by sunlight, 2FeK3(0204) 3 = 2FeK2(C204) 2+ K2C204+2C02.

In solution minute quantities of gold may be detected by the formation of " purple of Cassius," a bluish-purple precipitate thrown down by a mixture of ferric and stannous chlorides.

Oxidizing agents (ferric chloride, &c.) give a blue precipitate with solutions of its salts.

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.

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.

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.

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.

With a pure ferric salt it only gives a brown coloration.

The metallic cyanides may be detected by adding ferrous sulphate, ferric chloride, and hydrochloric acid to their solution, when a precipitate of Prussian blue is produced; if the original solution contains free acid it must be neutralized by caustic potash before the reagents are added.

The excess of reagent is removed by evaporation and a small quantity of a ferric salt added, when a deep red colour is produced.

It is basic in character, and gives a red coloration on the addition of ferric chloride.

He mentioned as an important exception the case of ferric ferrocyanide, which, when dissolved in oxalic acid, transmits the rays in great abundance, though the same rays be absorbed both by ferrocyanides and by ferric salts.

At A we 66 have the freezing point of pure water, which is lowered by the gradual addition of 46 ferric chloride in the manner shown by the curve AB.

The ferric hydrate is also readily deposited from ferruginous waters, often by means of organic agencies.

The American bauxites contain from 38 to 67% of alumina, from 1 to 23% of ferric oxide, and from 1 to 32% of silica.

After two or three hours the liquid is diluted till its density falls to 1.23, when it is passed through filter-presses to remove the insoluble ferric oxide and silica.

These exhibit, in certain cases, marked crystallographical and other analogies with the corresponding salts of chromium and ferric iron.

On exposure to meteoric influences pyrites commonly becomes brown, by formation of ferric hydrate or limonite, whence the change is called "limonitization."

Another kind of alteration which pyrites may suffer has been termed "vitriolization," since the products are ferrous sulphate, with free sulphuric acid and sometimes a basic ferric sulphate.

With ferric chloride it gives a dark-blue precipitate of a-dinaphthol, HO C10H6 C10H6.

With ferric chloride it gives a blue coloration.

Hydrogen is a very powerful reducing agent; the gas occluded by palladium being very active in this respect, readily reducing ferric salts to ferrous salts, nitrates to nitrites and ammonia, chlorates to chlorides, &c.

It is necessary that it should be as pure as possible since the commercial product usually contains traces of ferric, manganic and aluminium oxides, together with some silica.

Soc., 1900, 77, p. 69), and sugars are readily oxidized in the presence of ferric chloride (0.

It may be recognized by the violet coloration it gives when added to a very dilute solution of potassium bichromate in the presence of hydrochloric acid; by the orange-red colour it gives with a solution of titanium dioxide in concentrated sulphuric acid; and by the precipitate of Prussian blue formed when it is added to a solution containing ferric chloride and potassium ferricyanide.

The iron and aluminium precipitates are filtered off, and the filtrate boiled, when a basic beryllium hydroxide containing a little ferric oxide is precipitated.

Primarily but a slight deposit is formed (none until the concentration arrives at specific gravity 1.0509), this deposit consisting for the most part of calcium carbonate and ferric oxide.

Rock-salt when pure is colourless and transparent, but is usually red or brown by mechanical admixture with ferric oxide or hydroxide.

Thus the silica may range from 19 to 27%, the alumina and ferric oxide jointly from 7 to 14%, the lime from 60 to 67%.

The remaining silicates and aluminates present, and ferric oxide and magnesia, if existing in the moderate quantities which are usual in Portland cement of good quality, are of minor importance and may be regarded as little more than impurities.

The function of the ferric oxide present in ordinary cement is little more than that of a flux to aid the union of silica, alumina and lime in the clinker; its role in the setting of the cement is altogether secondary.

English hydraulic limes are of a different class; they contain a good deal of alumina and ferric oxide, and in composition resemble somewhat irregular Portland cement.

They are readily decomposed by mineral acids with the production of benzoic acid, and on addition of ferric chloride to their neutral solutions give a reddish-brown precipitate of ferric benzoate.

The ferric and aluminium sulphates present are thus converted into insoluble basic salts, and the residue yields manganous sulphate when extracted with water.

With ferric chloride it forms a deep red colour.

Chalcopyrite is decomposed by nitric acid with separation of sulphur and formation of a green solution; ammonia added in excess to this solution changes the green colour to deep blue and precipitates red ferric hydroxide.

Iodine, antimony trichloride, molybdenum pentachloride, ferric chloride, ferric oxide, antimony, tin, stannic oxide and ferrous sulphate have all been used as chlorine carriers.

The commercial acid is usually yellow in colour and contains many impurities, such as traces of arsenic, sulphuric acid, chlorine, ferric chloride and sulphurous acid; but these do not interfere with its application to the preparation of bleaching powder, in which it is chiefly consumed.

Numerous salts of the acid are known, the basic ferric salt being occasionally used in quantitative analysis for the separation of iron from aluminium.

It may be distinguished from the isomeric ethylene succinic acid by the fact that its sodium salt does not give a precipitate with ferric chloride.

Ores in which the copper is present as oxide or carbonate are soluble in sulphuric or hydrochloric acids, ferrous chloride, ferric sulphate, ammoniacal compounds and sodium thiosulphate.

When using iron as the precipitant, it is desirable that the solution should be as neutral as possible, and the quantity of ferric salts present should be reduced to a minimum; otherwise, a certain amount of iron would be used up by the free acid and in reducing the ferric salts.

The conversion of copper sulphide into the chlorides may be accomplished by calcining with common salt, or by treating the ores with ferrous chloride and hydrochloric acid or with ferric chloride.

This consists in stacking the broken ore in heaps and adding a mixture of sodium sulphate and ferric chloride in the proportions necessary for the entire conversion of the iron into ferric sulphate.

The heaps are moistened with ferric chloride solution, and the reaction is maintained by the liquid percolating through the heap. The liquid is run off at the base of the heaps into the precipitating tanks, where the copper is thrown down by means of metallic iron.

The ferrous chloride formed at the same time is converted into ferric chloride which can be used to moisten the heaps.

The tannin of oak, C/9H16010, which is found, mixed with gallic acid, ellagic acid and quercite, in oak bark, is a red powder; its aqueous solution is coloured dark blue by ferric chloride, and boiling with dilute sulphuric acid gives oak red or phlobaphene.

In many of the lakes of Sweden there is still in progress the formation of an iron ore, called sjomalm, ferric hydroxide, deposited in forms resembling peas, coins, &c., and used for the manufacture of iron.

Chalybeate waters, pools in marshes near irons one, &c., abound in bacteria,, some of which belong to the remarkable genera Crenothrix, Cladothrix and Leptothrix, and contain ferric oxide, i.e.

The ferric hydroxide accumulates in the sheath, and gradually passes into the more insoluble ferric oxide.

Ferric chloride colours its aqueous solution a dark violet, and bromine water precipitates tribromresorcin.

The methods used in the assay for iron are volumetric, and are all based on the property possessed by certain reagents of oxidizing iron from the ferrous to the ferric state.

It is necessary in the first place, after the ore is in solution, to reduce all the iron to the ferrous condition; then the carefully standardized solution of the oxidizing reagent is added until all the iron is in the ferric state, the volume of the standard solution used being the measure of the iron contained in the ore.

This solution, which should not exceed 50 cc. or 75 cc. in volume, contains the iron in the ferric state and is ready for reduction.

It seems to be a sublimation-product formed in volcanoes by the interaction of the vapour of ferric chloride and steam.

Ferric chloride gives a green coloration with the aqueous solution, whilst the alkaline solution rapidly changes to a green and finally to a black colour on exposure to the air.

The action of bromine is sometimes accelerated by the use of compounds which behave catalytically, the more important of these substances being iodine, iron, ferric chloride, ferric bromide, aluminium bromide and phosphorus.

With ferric salts its solution gives a deep blue colour, and with ferrous salts, after exposure to the air, an insoluble, blue-black, ferroso-ferric gallate.

Flue-dust contains principally ferric oxide, zinc oxide, arsenious and sulphuric acids, and small quantities of the various metals occurring in the raw ore.

Fuming or Nordhausen Oil of Vitriol, a mixture or chemical com pound of H 2 SO 4, with more or less S03, has been made for centuries by exposing pyritic schist to the influence of atmospheric agents, collecting the solution of ferrous and ferric sulphate thus formed, boiling it down into a hard mass ("vitriolstein") and heating this to a low red heat in small earthenware retorts.

It dissolves in dilute cold nitric acid with the formation of ferrous and ammonium nitrates, no gases being liberated; when heated or with stronger acid ferric nitrate is formed with evolution of nitrogen oxides.

The first two give origin to well-defined series of salts, the ferrous salts, wherein the metal is divalent, and the ferric salts, wherein the metal is trivalent; the former readily pass into the latter on oxidation, and the latter into the former on reduction.

Ferrous oxide is obtained when ferric oxide is reduced in hydrogen at 300 as a black pyrophoric powder.

Ferric oxide or iron sesquioxide, Fe203, constitutes the valuable ores red haematite and specular iron; the minerals brown haematite or limonite, and gothite and also iron rust are hydrated forms. It is obtained as a steel-grey crystalline powder by igniting the oxide or any ferric salt containing a volatile acid.

Small crystals are formed by passing ferric chloride vapour over heated lime.

Ferric oxide is employed as a pigment, as jeweller's rouge, and for polishing metals.

Thomas Graham obtained a soluble hydrate by dissolving the freshly prepared hydrate in ferric chloride and dialysing the solution, the soluble hydrate being left in the dialyser.

A similar compound, which, however, dissolves in water to form an orange solution, results by adding salt to a heated solution of ferric chloride.

Red ferric hydroxide dissolves in acids to form a well-defined series of salts, the ferric salts, also obtained by oxidizing ferrous salts; they are usually colourless when anhydrous, but yellow or brown when hydrated.

It dissolves in acids to form a mixture of a ferrous and ferric salt,' and if an alkali is added to the solution a black precipitate is obtained which dries to a dark brown mass of the composition Fe(OH)2Fe203; this substance is attracted by a magnet, and thus may be separated from the admixed ferric oxide.

Fremy investigated this discovery, made by Stahl in 1702, and showed that the same solution resulted when chlorine is passed into strong potash solution containing ferric hydrate in suspension.

Ferrous fluoride, FeF21 is obtained as colourless prisms (with 8H2O) by dissolving iron in hydrofluoric acid, or as anhydrous colourless rhombic prisms by heating iron or ferric chloride in dry hydrofluoric acid gas.

Ferric fluoride, FeF 31 is obtained as colourless crystals (with 42H2O) by evaporating a solution of the hydroxide in hydrofluoric acid.

When heated in air it yields ferric oxide.

Ferrous chloride, FeC1 21 is obtained as shining scales by passing chlorine, or, better, hydrochloric acid gas, over red-hot iron, or by reducing ferric chloride in a current of hydrogen.

Heated in air it yields a mixture of ferric oxide and chloride, and in steam magnetic oxide, hydrochloric acid, and hydrogen.

Ferric chloride, FeCl31 known in its aqueous solution to Glauber as oleum martis, may be obtained anhydrous by the action of dry chlorine on the metal at a moderate red-heat, or by passing hydrochloric acid gas over heated ferric oxide.

Many oxychlorides are known; soluble forms are obtained by dissolving precipitated ferric hydrate in ferric chloride, whilst insoluble compounds result when ferrous chloride is oxidized in air, or by boiling for some time aqueous solutions of ferric chloride.

Ferric bromide, FeBr31 is obtained as dark red crystals by heating iron in an excess of bromine vapour.

It closely resembles the chloride in being deliquescent, dissolving ferric hydrate, and in yielding basic salts.

Ferric iodide does not appear to exist.

Heated in air it at first partially oxidizes to ferrous sulphate, and at higher temperatures it yields sulphur dioxide and ferric oxide.

It is also prepared by precipitating a ferric salt with ammonium sulphide; unless the alkali be in excess a mixture of ferrous sulphide and sulphur is obtained.

Potassium ferric sulphide, K2Fe2S4, obtained by heating a mixture of iron filings, sulphur and potassium carbonate, forms purple glistening crystals, which burn when heated in air.

Pyrite may be prepared artificially by gently heating ferrous sulphide with sulphur, or as brassy octahedra and cubes by slowly heating an intimate mixture of ferric oxide, sulphur and salammoniac. It is insoluble in dilute acids, but dissolves in nitric acid with separation of sulphur.

The chief impurities are copper and ferric sulphates; the former may be removed by adding scrap iron, which precipitates the copper; the latter is eliminated by recrystallization.

Ferric sulphate, Fe2(S04)3, is obtained by adding nitric acid to a hot solution of ferrous sulphate containing sulphuric acid, colourless crystals being deposited on evaporating the solution.

It is sparingly soluble in water, and on heating it yields ferric oxide and sulphur dioxide.

The iron alums are obtained by crystallizing solutions of equivalent quantities of ferric and an alkaline sulphate.

Ferric potassium sulphate, the common iron alum, K2SO4Fe2(SO 4)3.24H2O, forms bright violet octahedra.

Ferric nitrate, Fe(NO3) 3, is obtained by dissolving iron in nitric acid (the cold dilute acid leads to the formation of ferrous and ammonium nitrates) and crystallizing, when cubes of Fe(NO3)3.6H20 or monoclinic crystals of Fe(N03)3.9H20 are obtained.

Ferric chloride also absorbs the gas.

Reddish brown amorphous powders of the formulae 2FeC1 3NO and 4FeC13NO are obtained by passing the gas over anhydrous ferric chloride.

The heptanitroso acid is precipitated as a brown amorphous mass by dilute sulphuric acid, but if the salt be heated with strong acid it yields nitrogen, nitric oxide, sulphur, sulphuretted hydrogen, and ferric, ammonium and potassium sulphates.

Normal ferric phosphate, FePO4.2H2O, occurs as the mineral strengite, and is obtained as a yellowish-white precipitate by mixing solutions of ferric chloride and sodium phosphate.

Arsenides, Arsenites, &c. - Several iron arsenides occur as minerals; lolingite, FeAs 2, forms silvery rhombic prisms; mispickel or arsenical pyrites, Fe2AsS2, is an important commercial source of arsenic. A basic ferric arsenite, 4Fe2O3 As2O3.5H 2 O, is obtained as a flocculent brown precipitate by adding an arsenite to ferric acetate, or by shaking freshly prepared ferric hydrate with a solution of arsenious oxide.

The last reaction is the basis of the application of ferric hydrate as an antidote in arsenical poisoning.

Normal ferric arsenate, FeAs0 4.2H2O, constitutes the mineral scorodite; pharmacosiderite is the basic arsenate 2FeAsO4Fe(OK)3.5H2O.

An acid arsenate, 2Fe2(HAsO4)3.9H20, is obtained as a white precipitate by mixing solutions of ferric chloride and ordinary sodium phosphate.

A soluble carbonate and a ferric salt give a precipitate which loses carbon dioxide on drying.

The halogens give ferrous and ferric haloids and carbon monoxide; hydrochloric and hydrobromic acids have no action, but hydriodic decomposes it.

Ferrous salts give a greenish precipitate with an alkali, whilst ferric give a characteristic red one.

Ferrous salts also give a bluish white precipitate with ferrocyanide, which on exposure turns to a dark blue; ferric salts are characterized by the intense purple coloration with a thiocyanate.

Liquor ferri perchloridi fortis, strong solution of ferric chloride (strength, 22.5% of iron); its preparations only are prescribed, viz.

Substances containing tannic or gallic acid turn black when compounded with a ferric salt, so it cannot be used in combination with vegetable astringents except with the infusion of quassia or calumba.

Ferri hydroxidum (U.S.P.), the hydrated oxide of iron, made by precipitating ferric sulphate with ammonia, is used solely as an antidote in arsenical poisoning.

Ferratogen is prepared from ferric nuclein.

Externally, it is not absorbed by the unbroken skin, but when applied to the broken skin, sores, ulcers and mucous surfaces, the ferric salts are powerful astringents, because they coagulate the albuminous fluids in the tissues themselves.

In the stomach all salts of iron, whatever their nature, are converted into ferric chloride.

In the intestine the ferric chloride becomes changed into an oxide of iron; the sub-chloride is converted into a ferrous carbonate, which is soluble.

It precipitates platinum, gold and silver from solutions of their salts, and also reduces mercuric, cupric and ferric salts.

Then, if available, freshly precipitated ferric hydrate must be given, which can be prepared by adding a solution of ammonia to one of iron perchloride.

Ferric chloride gives a bluishviolet coloration with the aqueous solution.

Although aniline is but feebly basic, it precipitates zinc, aluminium and ferric salts, and on warming expels ammonia from its salts.

It also appears that rust changes in composition on exposure to the atmosphere, both the ferrous oxide and carbonate being in part oxidized to ferric oxide.

The chemical bodies which have played the most important part as agents of petrifaction are silicic acid and calcium carbonate, though other substances, such as magnesium carbonate, calcium sulphate and ferric oxide have also been concerned, either as the chief constituents of petrifac tions, or mixed with other bodies.

Gault); (5) oxides of iron (staining the clay bright red when ferric oxide, red ochre; yellow when hydrous, e.g.

Gum arabic is not precipitated from solution by alum, stannous chloride, sulphate or nitrate of copper, or neutral lead acetate; with basic lead acetate it forms a white jelly, with ferric chloride it yields a stiff clear gelatinoid mass, and its solutions are also precipitated by borax.

Among such substances are fireclay and firebricks, certain sandstones, silica in the form of ganister, and Dinas stone and bricks, ferric oxide and alumina, carbon (as coke and graphite), magnesia, lime and chromium oxide - their relative importance being indicated by their order, the last two or three indeed being only of limited use.

Ferric oxide, though not strictly infusible, is largely used as a protecting lining for furnaces in which malleable iron is made, a portion of the ore being reduced and recovered in the process.

In an oxidizing atmosphere it is indifferent to silica, and therefore siliceous bricks containing a considerable proportion of ferric oxide, when used in flues of boilers, brewers' coppers, &c. and similar situations, are perfectly fire-resisting so long as the heated gas contains a large proportion of unconsumed air.

Return to DIAGRAM Disposal of iron residues The waste product from the ion exchange was ferric chloride.

Citrate - ferric ammonium citrate - ferric ammonium citrate - iron deficiency Nux vomica - stimulant of gastrointestinal tract, increase appetite.

Ferrous iron (e.g. ferrous sulfate) is much better absorbed than ferric iron (e.g. ferric citrate ).

As it exists today, the third era was enriched with minerals dominated by ferric oxides.

Normal (or ferric) tapes should be chosen from reputable manufacturers such as BASF, TDK, Maxell or Agfa.

When unaltered and containing no ferric oxide, the mineral is colourless, but on exposure to the light it very soon becomes of a characteristic indigo-blue colour.

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.

He inferred that chromic acid must contain only three atoms of oxygen, as did sulphuric acid SO 3; consequently chromic oxide, which contains half the amount of oxygen, must be Cr 2 O 3, and hence ferric oxide must be Fe203.

The complete conversion of stannous into stannic chloride may be effected by a great many reagents - for instance, by chlorine (bromine, iodine) readily; by mercuric chloride in the heat, with precipitation of calomel or metallic mercury; by ferric chloride in the heat, with formation of ferrous chloride; by arsenious chloride in strongly hydrochloric solutions, with precipitation of chocolate-brown metallic arsenic. All these reactions are available as tests for "stannosum" or the respective agents.

The ore was crushed roasted, and leached with sulphuric acid (with or without ferric sulphate); the solution was purified and then electrolysed for zinc with lead anodes and with a currentdensity of 5 amperes per sq.

The conversion into sulphate is generally effected by the oxidizing processes of weathering, calcination, heating with iron nitrate or ferric sulphate.

Ferric sulphate is only used as an auxiliary to the weathering process and in an electrolytic process.

By fusing iron with saltpetre and extracting the melt with water, or by adding a solution of ferric nitrate in nitric acid to strong potash, an amethyst or purple-red solution is obtained which contains potassium ferrate.

Crace-Calvert in 1871 showed that the carbon dioxide of the atmosphere was a factor; and in 1888 Crum Brown published the theory - termed the "carbonic acid theory" - that water and carbon dioxide react with iron to form ferrous carbonate and hydrogen, the ferrous carbonate being subsequently oxidized by moist oxygen to ferric hydrate and regenerating carbon dioxide, which again reacts with more iron.

If silica be present, it gives the iron bead when heated with a little ferric oxide; if tin is present there is no change.

To tin cast-iron articles they must be decarburetted superficially by ignition within a bath of ferric oxide (powdered haematite or similar material), then cleaned with acid, and tinned by immersion, as explained above.

The word "flocculent" is used of many substances which have a fleecy or "flock"-like appearance, such as a precipitate of ferric hydrate.