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1.
With the help of the chevenard thermobalance the authors have established the following limits for drying or ashing, of thallium derivatives before weighing. Trioxide prepared chemically: 126° to 230°; trioxide prepared electrolytically: 156° to 283°; chloride: 56° to 425°; iodide. 70° to473°; sulphate : 92° to 355°; luteocobaltic thalliumchloride :50° to 210°; chromate : 97° to 745°; hexachloroplatinate: 65° to 155°; thionalide complex: 69° to 156°; mercaptobenzothiazole complex: 52° to 217°.The two trioxides which have been prepared show signs of a transitory formation of 3Tl2O3.Tl2O on heating, but above 600° they behave differently. The chemically prepared trioxide shows two ranges of thermal stability. 相似文献
2.
With the help of the chevenard thermobalance, the authors have traced and examined the thermolysis curves of the precipitates proposed for the determination of zirconium. The methods in which picric acid, potassium iodate, ammonium arsenate and oxine are used, have been rejected; those in which ammonia, aniline, diethylaniline and in particular mandelic acid are used, are recommended for the automatic determination of zirconium. Zirconium hydroxide can be prepared in a pure state by means of aniline, while various other reagents smoothly afford zirconyl hydroxide. The problem of reduction of zirconium by pyrolysis of its arsenic(V) derivatives has been posed but not solved. 相似文献
3.
The four salts normally used for the gravimetric determination of lithium have been submitted to pyrolysis with the aid of the chevenard thermobalance. To obtain correct results it is necessary to heat the chloride between 175° C, and 606° C, the sulphate above 160°, the phosphate above 450° C, and the aluminate above 471°. 相似文献
4.
The three gravimetric methods so far proposed for the determination of lanthanum have been tried out experimentally. The oxide prepared from the hydroxide must be heated to at least 944° and that obtained from the oxalate at not less than 876°. The basic carbonate reaches almost constant weight between 700° and 800°. Finally the oxinate should be kept at 130°. 相似文献
5.
A zirconium-free oxychloride of hafnium was prepared. The hafnium can be determined gravimetrically from the thermolysis curves of the precipitate. In particular, the neutral selenate, the p-hydroxyphenylarsinate and the mandelate were studied, and the curves obtained were compared to those plotted of the homologous zirconium derivatives. 相似文献
6.
In the gravimetric determination of samarium, it is necessary to ignite the hydroxide above 813° and the oxalate above 800° in order to ensure complete transformation to the oxide Sm2O3 . 相似文献
7.
The authors show that rhodium is not so easily oxidized, as one has up to now supposed. It is possible to weigh the metal up to 550°. They propose 2 new forms of weighing with the help of the internal complexes which can be formed with thionalide and mercapto-2-benzoxazole. 相似文献
8.
With the object of determining the best conditions of temperature to be used by the analyst for weighing to constant weight precipitates containing calcium, the authors made a detailed study of the curves of pyrolysis which they have recorded by means of the Chevenard thermobalance. The following were studied : oxalate, carbonate, oxide, precipitated sulphate and gypsum, fluoride, iodate, arsenate, molybdate, tungstate, nickel-hexanitrite, tartrate, 8-hydroxyquinolate, and picrolonate. They suggest a rapid method for the analysis of the sulphate and carbonate of calcium in gypsum, a. new gravimetric determination by electrolysis of nickel-hexanitrite of calcium-potassium, of which the structural formula has been established. Finally, they recommend, in the case of precipitation of calcium as the tartrate, weighing as carbonate rather than oxide. 相似文献
9.
With the help of the Chcvcnard thcrmobalancc the authors have determined the minimum temperatures necessary for quantitatively converting the derivatives of gallium into oxide Ga203.
Hydroxide by ammonium hydroxide | 408° | |
Hydroxide by ammonia | 400° | |
Hydroxide by urea | 475° | |
Hydroxide by aniline | 546° | |
Hydroxide by sulpliitc | 813° | |
Hydroxide by tannin | 520° | |
Cupfcrron | 745° | |
Camphoratc | 478° | |
Dibromo-oxinate | 817° |
Réactif précipitant | Forme de pesée | Limites de température |
Electrolyse | Hg | <70° |
Zinc + Iodure de potassium | Hg | <72° |
Hydrazine | Hg | <55° |
Acide hypophosphoreux | Hg | <71° |
Acide nitrique | HgO | 100°–200° |
Acide chlorhydrique | Cl2Hg2 | <130° |
*Iodure de potassium | I2Hg | 45°–88° |
*Iodate de potassium | (IO3)2Hg2 | <175° |
Periodate de potassium | (IO3)2Hg2 | <175° |
Sulfure d'ammonium | SHg | <109° |
*Thiosulfate de sodium | SHg | 75–220° |
Arséniate disodique | (AsO4)2Hg3 | 45–418° |
*Thiocyanate de cobalt | [Hg(SCN)4]Co | 50–200° |
Thiocyanate de zinc | [Hg(SCN)4]Zn | <270° |
*Chromate de potassium | CrO4Hg2 | 52–256° |
Chromate de potassium ammoniacal | CrO4Hg2 | 52–256° |
*Bichromate d 'ammonium + Pyridine | Cr2O7[Hg(C5H5N)2] | 56–66° |
*Sel de Reinecke | [Cr(CNS)4(NH3)2]2Hg | 77–158° |
Molybdate alcalin | [Cr(CNS)4(NH3)2]2Hg | 77–158° |
Tungstate alcalin | WO3 | >880° |
Vanadate alcalin | WO3 | >880° |
Iodure de cadmium ammoniacal | (HgI3)2[Cd(NH3)4] | <69° |
Iodure de potassium + Sulfate de cuivre + Ethylène diamine | [HgI4][Cu En2] | à 20° |
*Iodure de potassium + Sulfate de cuivre + Propylène diamine | [HgI4][Cu Pn2] | <157° |
Acide oxalique | C2O4Hg2 | <100° |
Anthranilate de sodium | (C6H6O2N)2Hg | <113° |
Pyridine | Cl2Hg(C5H5N) | <113° |
Dithiane | Cl2Hg.C4H8S2 | <97° |
*Chlorure de cuivre-biguanide + iodure de potassium | [HgI4][Cu(C2N5H7)2] | 60–175° |
Cupferron | [HgI4][Cu(C2N5H7)2] | 60–175° |
*Thionalide | (C12H10ONS)2Hg | 90–169° |
Chloro-2 méthoxy-7 thiol-5 acridine | (C12H10ONS)2Hg | 90–169° |
Precipitating reagent | Form in which weighed | Temperature limits |
Ammonium hydroxide (to a chromic salt) | Cr2O3 | > 812° |
Ammonium hydroxide (to chromic acid) | Cr2O3 | > 188° |
Ammoniac (gas) | Cr(OH)3 | 440–475° |
Ammoniac (gas) | Cr2O3 | > 845° |
Aniline | Cr2O3 | > 830° |
Hydroxylamine | Cr2O3 | > 850° |
Thiosemicarbazide | Cr2Oa3.H2O | 380–410° |
Thiosemicarbazide | Cr2O3 | > 475° |
Potassium cyanate | Cr2O3.H2O | 320–370° |
Potassium cyanate | Cr2O3 | > 473° |
Ammonium nitrite | Cr2O3 | > 880° |
Potassium iodo-iodate | Cr2O3 | > 850° |
Disodium phosphate | CrPO4 | > 946° |
Silver nitrate | Ag2CrO4 | 92–812° |
Mercurous nitrate | Hg2CrO4 | 82–256° |
Mercurous nitrate | Cr2O3 | > 671° |
Barium nitrate | BaCrO4 | < 60° |
Lead nitrate | PbCrO4 | 91–904° |
8-Hydroxyquinoline | Cr(C9H6ON)3 | 70–156° |
8-Hydroxyquinoline | Cr2O3 | > 500° |
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