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Germanium

This new element, which is exciting considerable attention among chemists, was discovered by Clemens Winkler, of Freiburg, in the early part of the year 1886. The constant error of about six per cent. in the result of his analysis of a comparatively simple mineral led him to suspect the presence of one or more new elements. Such a suspicion was well founded, and, as the result of an exceedingly careful and painstaking investigation, he succeeded in isolating a new substance, which conducts itself in every way like an element; and, what is of still more general interest, a careful study of this new simple body and the compounds which it forms with other elements shows, it can be said almost conclusively, that it agrees in properties with the eka- siliciUtn of Mendelejeff. The silver ore from which germanium is obtained, and which is now known in mineralogy as argyrodite, is found in the neighborhood of Freiburg, and the analysis of the mineral has shown it to have the composition represented by the form ula 3AgaS, GeSj. According to this, it may be regarded as a sulpho salt for which mineralogy furnishes no analogues. In order to extract germanium, the mineral in which it occurs is fused with an equal weight of a mixture of equal parts of flowers of sulphur and !'oda ash. The fused mass it! then boiled with caustic soda, and the solution thus obtained is neutralized with dilute sulphuric acid. This is then filtered. To the filtrate dilute sulphuric acid is again added, when the sulphide of germanium is thrown down. This is filtered off and washed with dilute acid containing hydrogen sulphide, and finally, by treating the washed precipitate with strong nitric acid and evaporating to dryness, germanium oxide is obtained, which may be reduced either by heating to redness in a current of hydrogen or by heating a mixture of the oxide and starch in a covered crucible. Ill- this way germanium is obtained in the form of a dark gray powder, which melts ullIiler borax glass at 900° C. The element is found to be extraordinarily brittle, and to have a strong tendency to crystallize in the regular system. It has a fine metallic luster. In color' it is grayish white, considerably whiter than zirconium. At 20'4° C. it has been found to have a specific gravity of 5 469. Germanium is not acted on by hydrochloric acid, but is easily dissolved in aqua regia. Nitric acid converts it into a white oxide with liberation of the oxides of nitrogen. Treated with concentrated sulphuric acid, it yields a white, crystalline sulphate, sulphur dioxide being liberated in a constant stream during the action. It is not acted on by potassium hydroxide in the cold. The atomic weight of germanium has been determined by two entirely different methods: 1st, volume- trically, by determining the amount of chlorine ill the tetra-chloride, GeCh, according to the method of Vol- hard; and, 2d, from calculations based on the wave lengths of certain lines in the spark spectrum. By the former method the atomic weight has been found to be 72'32; by the latter 72'28. The very close agreement of this number 72'28, as representing the atomic weight of the new element, with that of the unknown element between gallium and arsenic on the one hand and titanium and zirconium on the other, in the table of Mendelejeff, has naturally led to a very careful comparison of the properties of germanium with those of eka-sili- cium, whose properties were predicted by Mendelejeff as early as 1871. The results of the comparison will be best seen by presenting them in tabular form: Eka-Silicium, Es. Atomic weight, about 72 Density, 5'5. Atomic volume, 13 nearly. Will form an oxide, GeOa. Sp. gr., 4'7. Easily obtained by reduction with carbon or sodium. A dirty gray metal, fusible with difficulty, forming the oxide when heated in air. Will form a chloride of the composition EsCh, which will boil near 100° C., probably lower. EsO2 will form a hydrate soluble in acids. This solution will probably decompose readily, yielding an insolu ble hydrate. The sulphide will be insoluble in water, but probably soluble in ammonium sulphide. The metal will decompose steam very slowly, be scarcely acted on by acids. but easily by alkalies. Germanium, (Ie. Atomic weight, 72 32 and 72'28 Density, 5'469. Atomic volume, 1325. Forms an oxide, GeOa. Sp. gr., 4 703. Easily obtained by reduction with carbon or hydrogen. A gray white metal, fus ing at 900° C., and forming the oxide when heated in air. Forms a chloride having the composition GeC!«, which boils at 86° C. It will form volatile or- gano-metallic compounds, and will occur in minerals containing titanium and niobium. According to L. Meyer, this element will be: Easily fusible, Volatile, Electro-negative, Brittle. The sulphide is moderately soluble in water, more readily so1u ble in ammonium sulphide and the alkalies. Not acted on by hydrochloric acid. Soluble in aqua regia. Nitric acid converts it into the oxide. Sulphuric acid gives the sulphate with liberation of sulphur dioxide. Not acted on by a concentrated solution of potassium hydroxide, but violently by the molten hydroxide. Occurs in a silver ore of composition 3Ag.S,GeS. Fuses at 900° C., Easily volatile, Probably electro-negative, Very brittle. A comparison like this shows that we have here to deal with a case similar to that which presented itself when gallium and scandium were discovered, andshown to be identical with eka-aluminum and eka- boron respectively, and a careful consideration of the results aIready obtained seems to show that, in all probability, the eka-silicium of Mendelejeff and the germanium discovered by Winkler are the same elements. —Journal fur prak. Chemie, 34, 177; Amer. Chem. Jour., J. H. K

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