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Action of Ferric Sulphate on Iron. By A. E. MENKE (Amer. Chem. J., 9, 90-93).-The action increases approximately with the amount of ferric sulphate, whether at a boiling temperature or in sealed tubes at 110°. The addition of the theoretical amount of sodium or potassium carbonate necessary for the precipitation of the iron salt reduces the action to about one-third, but calcium carbonate has no effect, or not so much; the action is less on steel than on boiler plate. H. B.

Titanium Carbide in Pig-iron. By P. W. SHIMER (Chem. News, 55, 156-158).-From the residue left on dissolving 250 grams of pig-iron in dilute hydrochloric acid, the author separated about 1 gram of a material consisting largely of minute, cubical, metallic crystals. Analysis showed that 88 per cent. of this material was composed of titanium and carbon very nearly in atomic proportions; the crystals are therefore regarded as a titanium carbide, TiC. The five or six pig-irons examined all contained these crystals, and a sample of No. 1 Barrow foundry iron yielded 0-203 per cent. of titanium.

In separating the titaniferous material from the graphite, &c., in the residue, a very slightly inclined plane, 12 feet long and 5 inches wide, made of window glass, was made use of. The material was placed at the upper end, and water allowed to drip upon it slowly, by which the lighter particles were carried forward faster than the heavier crystals. R. R.

Formation of Complex Inorganic Acids. By E. DRECHSEL (Ber., 20, 1452-1455).-Silicotungstic acid can be readily prepared as follows:-Pure sodium tungstate is dissolved in a little boiling water, almost neutralised with nitric acid, and filtered. The crystals are washed with cold water, dissolved in water, and boiled with gelatinous silica until the solution no longer gives a precipitate with hydrochloric acid. It is filtered, evaporated, treated when cold with a large excess of sulphuric acid previously diluted with an equal volume of water, and allowed to cool. Ether is then gradually added, when the liquid becomes turbid and separates into three layers-the lowest oily and containing most of the silicotungstic acid; the middle layer an aqueous solution of hydrogen sodium sulphate and sulphuric acid; the upper layer ether. The lowest layer is separated, freed from ether by evaporating on a water-bath (avoiding too high a temperature), and allowed to cool. The acid separates in splendid crystals. When a concentrated aqueous solution of phosphotungstic acid is treated with an equal volume of ether, oily drops form at the surface of contact of the water and ether, and then sink, forming a third layer; the latter has the sp. gr. = 1.525. Crystallised phosphotungstic acid dissolved in the smallest amount of ether gives an oil, sp. gr. 2.083.

Phosphotungstic acid is prepared by dissolving 500 grams of pure sodium tungstate and 250 grams of crystallised sodium phosphate in 500 c.c. of water and evaporating until a skin is formed on the surface. 700 to 800 c.c. of hydrochloric acid (sp. gr. = 114) is added to the boiling solution, which is again evaporated and allowed to cool. The

whole is gradually treated with pure ether, being well shaken all the time, until a layer is formed above the acid solution. It is then left until the lower layer is clear, separated and treated with an equal volume of water; the ether is then evaporated; if the solution becomes bluish, chlorine water is added. It is evaporated to dryness, dissolved in hot water; on cooling the acid separates in splendid crystals.

Phosphomolybdic acid is prepared in a similar manner.

N. H. M. Equivalent and Atomic Weight of Thorium. By G. KRÜSS and L. F. NILSON (Ber., 20, 1665-1676).-The accepted value for the atomic weight of thorium is 2324, which is in accordance with the determinations of its specific heat.

In this paper, determinations are given of the equivalent of thorium and of the molecular weight of the chloride, and from these values, together with considerations of the position of the metal in the periodic system, the atomic weight is deduced.

The thorium oxide is prepared from the mixed sulphates obtained by dissolving thorite in sulphuric acid; from this solution, the hydrated oxides are precipitated by ammonia, subsequently dissolved in hydrochloric acid, and precipitated as oxalates. These last are converted into the sulphates, and from the mixed salts thorium sulphate is obtained by dissolving in ice-cold water, in which it is less soluble than the sulphates of the accompanying metals. This fractional crystallisation from ice-cold water is repeated several times. The sulphate crystallises with 8 mols. H2O. From the anhydrous salt, the equiva lent of the metal is determined by ignition and weighing the residual oxide; the mean value of eight concordant determinations is 57.997. The sp. gr. of the anhydrous sulphate is 4.2252.

Specimens of the chloride were obtained by heating the metal in a current of dry hydrochloric acid at a low red heat and subsequent resublimation of the salt. The percentage of chlorine found was 37.83 (theory requiring 37.89). Vapour-density determinations of different samples at temperatures varying from 1057° to 1270° gave values from 11.232 to 12·424; a determination at 1400° gave the value 9-835. The theoretical value for the chloride ThCl, is 12.928. The previous determinations of Troost, which varied from 5·9 to 7·49, were probably vitiated by impurities in the samples used.

Then as thorium is quadrivalent, no place being found for a bivalent metal of atomic weight 116 in the periodic system, as also from the values found for the sp. gr. of the anhydrous sulphate and oxide, the corrected atomic weight is taken as 231-813 to 231·916 (mean 231-87), oxygen being taken as 15.96. V. H. V.

Potassium Germanium Fluoride. By G. KRÜSS and L. F. NILSON (Ber., 20, 1696-1700).-Germanium fluoride is readily obtained in solution by dissolving the oxide in hydrofluoric acid; on evaporating the solution with sulphuric acid and subsequent ignition the oxide is re-formed. On adding potassium hydrogen fluoride to the solution of germanium fluoride, the double salt is precipitated at first as a gelatinous precipitate, which gradually becomes crystalline ;

on slowly evaporating the saturated solution, it separates in the form of tables or prisms. The salt can be heated to a red heat without alteration in weight. Its composition, K,GeF, was determined by evaporating the salt with sulphuric acid and igniting, and weighing the residue of the oxide GeO, and potassium sulphate. It is shown by crystallographic measurements (a: c 1: 08039) that this salt is isomorphous with ammonium silicofluoride. In conclusion, it is remarked that the properties of potassium germanium fluoride agree with those predicted by Mendelejeff for the corresponding salt of ekasilicon. V. H. V.

Alkaline Vanadates. By A. DITTE (Compt. rend., 104, 11681171). When a mixture of lithium carbonate (1 mol.) and vanadic anhydride (1 mol.) is boiled with water, and the solution concentrated to a thick syrup in a vacuum, it deposits brilliant, silky needles of the composition Li2O,V2Oь + 4H2O, which lose water when heated, and form a brown liquid, which solidifies to a crystalline mass of the anhydrous normal vanadate.

If a solution of the normal vanadate is acidified with acetic acid and evaporated in a vacuum, it deposits red transparent crystals with a brilliant lustre, which have the composition Li2O,2V20, + 12H,O. If crystallisation takes place in a warm solution, thin orange-red plates of the composition Li,O,2V2O, + 8H2O are obtained.

When lithium carbonate is boiled with an excess of vanadic anhydride, and the solution slightly acidified with acetic acid, and concentrated in a vacuum, it deposits orange-red crystals of the compound 2Li2O,3V20, + 16H2O.

All the hydrated acid salts when heated lose their water without melting and become deep red-brown. At a higher temperature, they melt to a brown liquid which solidifies to a crystalline mass on cooling.

If a solution of the normal vanadate is made strongly alkaline with lithia and concentrated in a vacuum, the syrupy liquid deposits silky, white needles of the compound 2Li2O,V2O5 + 6H2O, which lose water when heated, then melt, and solidify on cooling to a white, crystalline, nacreous mass of the composition 2Li2O,V2O5. If the mother-liquor from these crystals is concentrated, it deposits crystals of the compound 3Li,O,V2O5 + 6H2O.

Lithium carbonate solution saturated with vanadic anhydride, and mixed with a warm concentrated solution of lithia in large excess, almost immediately deposits the compound 4Li2O,V2O5 + H2O in transparent, microscopic crystals, which if left in contact with the mother-liquor change to bulky, colourless, transparent, rhomboidal crystals of the composition 4Li2O,V2O, + 14H.O. They lose water when heated, but the white, anhydrous salt is infusible even at a red heat.

A comparison of the various alkaline vanadates (Abstr., 1886, 671, and this vol., 639) shows that they are analogous in constitution, but contain different amounts of water of crystallisation according to the conditions under which they are formed. The normal salts are

colourless, the acid salts red with a more or less marked orange tint, and the basic salts are colourless. C. H. B.

Reduction of Potassium Niobium Fluoride with Sodium, By G. KRUSS and L. F. NILSON (Ber., 20, 1691—1696).—By heating potassium niobium fluoride with sodium, the mixture being protected by a layer of sodium chloride, Marignac obtained a black insoluble powder; this was found to consist of a hydride of niobium, NbH, mixed with a small quantity of niobic acid. In this paper, the experiments of Marignac are repeated; the product obtained on heating the mixture of potassium niobium fluoride, sodium, and sodium chloride, was treated at first with alcohol, then with water, and finally washed with ether. The product was a glistening, hygroscopic, black powder, unattacked by hydrochloric and nitric acids or aqua regia, but soluble in concentrated hydrofluoric acid with evolution of hydrogen. It burns in a current of dry hydrochloric acid gas with formation of four different chlorides of niobium, two of which are the more and two the less volatile in the gas. Analysis showed the composition of the product to be as follows: -NbH 77.5 per cent.; Nb2O5 = 21:53 per cent.; Fe2O2 = 0·97 per

cent.

The following determinations are also given of the molecular heats of niobium hydride and oxide:

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Earths and Niobic Acid from Fergusonite. By G. KRÜSS and L. F. NILSON (Ber., 20, 1676-1690.)-In this paper, a description is given of the qualitative separation of the various earths present in the mineral fergusonite, a large quantity of which was operated on. The two samples used came from Arendal and Ytterby.

Among the oxides of the rare metals found were those of cerium, thorium, erbium, samarium, thulium, ytterbium, and the various components of didymium, and of Soret's X. Among the acid-forming oxides were those of titanium, tantalum, and niobium.

In order to prepare pure niobic acid from the mineral, the aqueous solution of crude potassium niobium oxyfluoride is heated for some time to separate the oxyfluoride of potassium and tantalum, 2(2KF,TaF), Ta2O; on subsequent evaporation, the niobium oxyfluoride, 2KF,NbOF3, crystallises out, and from the determination of the ratio 2K2SO: Nb2O, obtained from the salt, the atomic weight of niobium is taken as 93.8. From the oxyfluoride, a sample of the double fluoride K2NbF, was obtained, and from the ratio 2K2SO: Nb2O2 the value 93-96 is deduced; these numbers are practically equal to the atomic weight 94 taken by Marignac. When a solution of potas sium niobium oxyfluoride is boiled, a double salt, 2KF,3NьO2F,

separates as a hard white powder consisting of minute crystals. The change which leads to its formation may be expressed thus:

3(2KF,NьOF,,H2O) = 2KF,3NьO2F + 4KHF, + 2HF.

V. H. V.

Mineralogical Chemistry.

Bismuthic Gold. By R. W. E. MACIVOR (Chem. News, 55, 191). -An analysis of bismuthic gold from Maldon, Victoria, gave gold 64-211; bismuth 34398; siliceous matter 1:391 per cent. The proportions of gold and bismuth indicate the formula Au,Bi.

R. R.

Enargite from Montana. By W. SEMMONS (Min. Mag., 6, 4951; Jahrb. f. Min., 1887, 1, Ref., 416-417).-The mineral examined was of a lead-grey colour, with a black streak; sp. gr. 4·3, hardness 2.5. Crystals are rare and always small. The crystals are rhombic prisms with brachypinacoid and macropinacoid, brachydomes and macrodomes. Analysis gave the following results :

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Analysis II gives the results calculated to 100, the silica and iron being considered as impurities. The mineral thus very closely resembles enargite in composition, but differs from it in cleavage, in hardness, and in behaviour before the blowpipe. It occurs with iron pyrites, bornite, covelline, and quartz in a number of mines in Montana, United States.

B. H. B.

Artificial Production of Rose Spinel or Balas Ruby. By S. MEUNIER (Compt. rend., 104, 1111-1112).—The bottom of a graphite crucible is covered with a layer of finely-powdered magnesia well rammed down, an intimate mixture of very finely-powdered aluminium chloride and cryolite is then introduced, and the crucible is filled up with alumina and magnesia, the latter being in excess. If a rosecoloured product is desired, a very small quantity of potassium dichromate is added. The crucible is heated for five or six hours in a good coke fire, and allowed to cool as slowly as possible. The product is a greyish gangue, full of vesicles which are lined with brilliant, rose-coloured crystals of balas ruby, identical with the natural crystals in form, colour, brilliancy, hardness, and optical properties. If cryolite is used without aluminium chloride, the product consists of rose-coloured lamellæ of corundum without any trace of spinel, even in presence of a large excess of magnesia.

Probably this is a further example of the mineralising action of fluorine recently described by Fremy (this vol., p. 556). The experiment may be varied in many ways, and the author has obtained a

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