|Reference : Sur la décomposition de quelques sulfates acides à la suite d'une déformation mécanique|
|Scientific journals : Article|
|Physical, chemical, mathematical & earth Sciences : Chemistry|
|Sur la décomposition de quelques sulfates acides à la suite d'une déformation mécanique|
|[en] Decomposition of some Acid Sulfates as the Result of Mechanical Deformation|
|Spring, Walthère [Université de Liège - ULg]|
|Bulletin de la Classe des Sciences. Académie Royale de Belgique|
|Académie Royale de Belgique|
|[en] Pressure ; Diffusion in solids ; Decomposition ; Sulfates ; Mechanical deformation|
|[fr] Pression ; Diffusion dans les solides ; Décomposition ; Sulfates ; Déformation mécanique|
|[en] Spring, W. Bulletin de la Classe des Sciences, Academie Royale de Belgique (1904), 1904, 290-309; SciFinder (Chemical Abstracts Service: Columbus, OH); https://scifinder.cas.org (accessed July 8, 2010).
There after earlier investigations of the authors, (see page 776), perhaps strong compression the same effect as increased temperature on firm body exercises, then it was to be assumed that crystal water-containing salts and acid salts will or less disintegrate with intensive mechanical deformation into their components. For examination the acid sulfates of the alkali metals were selected, with which, as the subsequent compilation shows, which is smaller molecular volume than the sum of the volumes of the developing decomposition products, which decomposition is connected with volume increase. Salt, Density, Molecular volumes. (* determined by the author). Li2SO4, 2.228 *, 2LiHSO4 = 98.1. LiHSO4, 2.123 *, Li2SO4 +. H2SO4 = 102.3. Na2SO4, 2.655, 2NaHSO4 = 98.6. NaHSO4, 2.435 with 13° *, Na2SO4 +. H2SO4 = 106.4. K2SO4 , 2.670, 2KHSO4 = 118. KHSO4, 2.302 with 13° * K2SO4 +. H2SO4 = 118.1. Rb2SO43.596 with 16° *, RbHSO4 = 125.8. RbHSO4, 2.892 with 16° *, Rb2SO4 +. H2SO4 = 126.9. Cs2SO44.250 with 16° * ,2CsHSO4 = 136.6. CsHSO4, 3.352 with 16° *, Cs2SO4 +. H2SO4 = 137.7. Since it not actually concerns around production of a simple hydrostatic pressure, but the effect of a pressing with deformation, the salts in a steel cylinder were pressed together, which possessed an opening, which permitted a "flow through" of the examined substance in the ground; Rise in temperature was completely impossible. The received results are the following. LiHSO4 separates due to pressing into an effluent acid-richer component (approximately 9LiHSO4•2H2SO4) and a part staying, which approaches the composition of the neutral salt. With that salts LiHSO4•H2O continues to go the decay still, whereby the water partly flows. With NaHSO4 no clear flow with occurring cleavage could be observed, on the other hand a clear cleavage occurs, in the discharge of a large quantity crystal water with different hydrates of the acid sulfate, in particular at somewhat increased temperature and a considerable quantity expresses H2SO4; at low temperature first water is separated. The salt 5NaHSO4• H2SO4• 7H2O develops with 40° liquid approximately the composition NaHSO4 has acid, the mass staying; with 80° the decomposition continues to go still, as a small quantity of Na2SO4 develops. The acid sulfates the pressing with 100°, applied by potassium, rubidium, cesium decomposing with; not; hereby it stands in the agreement that these salts are resistant in relation to the effect of the heat. In further experiments a mixture of NaHSO4 with different basic oxides : PbO, CuO, HgO, Ag2O, strong pressure suspended. In completely closed cylinder, without which possibility of flow stepped, like the continuous coloring showed no reaction . If against it the pressure with a mechanical deformation is accompanied (small opening in the ground), takes place a reaction up to complete neutralization of the H2SO4 contained in the acid sulfate; the same effect reached by simple grating, whereby CuO white CuSO4Na2• SO4• H2O gives. From the observations it follows except the analogy between heat effect and pressing still that so-called molecular compounds/connections are less resistant opposite the deformation than atomic compounds/connections. An explanation of the features follows from the conception that pressing causes a change of the molecular condition in the sense of a "pseudo fusion". These procedures have a great importance probably on geological of areas (ground pressure).
Reprinted with the permission of the American Chemical Society. Copyright © 2010. American Chemical Society (ACS). All Rights Reserved.
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|Voir aussi : http://hdl.handle.net/2268/67980
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