- Theoretical and Experimental Study of the Crystal Structures, Lattice Vibrations, and Band Structures of Monazite-Type PbCrO4, PbSeO4, SrCrO4, and SrSeO4
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The crystal structures, lattice vibrations, and electronic band structures of PbCrO4, PbSeO4, SrCrO4, and SrSeO4 were studied by ab initio calculations, Raman spectroscopy, X-ray diffraction, and optical-absorpt
- Errandonea, Daniel,Muoz, Alfonso,Rodrguez-Hernndez, Placida,Proctor, John E.,Sapia, Fernando,Bettinelli, Marco
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- A group of new selenite-chlorides of strontium and d-metals (Co,Ni): Synthesis, thermal behavior and crystal chemistry
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The new selenite-chlorides with composition Sr3(SeO3)2Cl2 (I) and Sr2M(SeO3)2Cl2 (M=Co, Ni (II and III)) were obtained. They crystallize in monoclinic system I: space
- Berdonosov, Peter S.,Olenev, Andrey V.,Kuznetsov, Alexei N.,Dolgikh, Valery A.
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- Novel alkali earth borohydride Sr(BH4)2 and borohydride-chloride Sr(BH4)Cl
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Two novel alkali earth borohydrides, Sr(BH4)2 and Sr(BH4)Cl, have been synthesized and investigated by in-situ synchrotron radiation powder X-ray diffraction (SR-PXD) and Raman spectroscopy. Strontium borohydride, Sr(BH4)2, was synthesized via a metathesis reaction between LiBH4 and SrCl2 by two complementary methods, i.e., solvent-mediated and mechanochemical synthesis, while Sr(BH4)Cl was obtained from mechanochemical synthesis, i.e., ball milling. Sr(BH4)2 crystallizes in the orthorhombic crystal system, a = 6.97833(9) A, b = 8.39651(11) A, and c = 7.55931(10) A (V = 442.927(10) A3) at RT with space group symmetry Pbcn. The compound crystallizes in α-PbO2 structure type and is built from half-occupied brucite-like layers of slightly distorted [Sr(BH4)6] octahedra stacked in the a-axis direction. Strontium borohydride chloride, Sr(BH4)Cl, is a stoichiometric, ordered compound, which also crystallizes in the orthorhombic crystal system, a = 10.8873(8) A, b = 4.6035(3) A, and c = 7.4398(6) A (V = 372.91(3) A3) at RT, with space group symmetry Pnma and structure type Sr(OH)2. Sr(BH4)Cl dissociates into Sr(BH4)2 and SrCl2 at ~170 C, while Sr(BH4)2 is found to decompose in multiple steps between 270 and 465 C with formation of several decomposition products, e.g., SrB 6. Furthermore, partly characterized new compounds are also reported here, e.g., a solvate of Sr(BH4)2 and two Li-Sr-BH 4 compounds.
- Ravnsbaek,Nickels,Cerny,Olesen,David,Edwards,Filinchuk,Jensen
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- Hydration of strontium chloride and rare-earth element oxychlorides
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Hydration and dehydration (on calcination) of SrCl2, YOCl, and HoOCl powders were studied.
- Basiev,Batyrev,Voronov,Konyushkin,Kuznetsov,Osiko,Samartsev,Samoilova,Fedorov
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- Enthalpies of formation of strontium dichloride and of the strontium ion (Sr2+) in water and in 1 mol * dm-3 HCl, and an assessment of enthalpies of formation of alkaline-earth dichlorides
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Measurements of the enthalpy of solution of SrCl2 in water and in 1 mol * dm-3 HCl solution lead to ΔHf0 (SrCl2, c, 298.15 K) = -(832.7 +/- 0.9) kJ * mol-1, and to ΔHf0 (Sr2+, aq, 298.15 K)
- Morss, Lester R.,Williams, Clayton W.
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- The standard enthalpies of formation of MO(s), MCl2(s), and M2+(aq,) (M = Ba, Sr)
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The enthalpies of solution of the oxides and chlorides and barium and strontium in 1.0 mol*dm-3 HCl(aq) and of the chlorides in H2O are reported.From these results the standard enthalpies of formation of BaO(s), SrO(s), BaCl2(s), SrCl2(s), Bas
- Cordfunke, E. H. P.,Konings, R. J. M.,Ouweltjes, W.
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- Strontium-copper selenite-chlorides: Synthesis and structural investigation
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Two new complex selenite-chlorides of strontium and copper Sr2Cu(SeO3)2Cl2 (I) and SrCu2(SeO3)2Cl2 (II) were obtained and characterized by X-ray diffraction technique,
- Berdonosov, Peter S.,Olenev, Andrei V.,Dolgikh, Valery A.
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- Ion-Ion-Solvent Interactions in Solution. XI Spectroscopic Studies of Group 2 Perchlorates in Acetone
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Solutions of Mg(ClO4)2 and Sr(ClO4)2 in acetone have been studied at various concentrations up to saturation by using infrared absorption, Raman scattering and multinuclear n.m.r. (1H, 13C, 17O, 25Mg, 35Cl).Solvation numbers of c. 4.5 (Mg2+) and c. 5.5 (Sr2+) were determined from component band analysis of the c. 800 cm-1 acetone band in the Raman spectra.The solvent shell about the Mg2+ had a high level of steric crowding.There was a small amount of solvent-shared ion-pair formation at all concentrations in solutions of Mg(ClO4)2 which showed little concentration dependence.In solutions of Sr(ClO4)2 there was evidence for the formation of both solvent-shared associated-ion species and ion-contact species.The solvent-shared species appeared to have two alternative configurations in one of which the anion was both polarized and highly hindered.There was a salt-promoted reaction in which the perchlorate was reduced to chloride and the solution darkened.This reaction prevented the use of Raman spectra to quantify the association equilibria.
- James, David W.,Cutler, Paul G.
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- Synthesis and structural characterization of new phases in the cubic M 3Te2O6X2 (M = Sr, Ba; X = Cl, Br) structure family
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Four alkaline earth oxotellurate(IV) halides with common formula M 3Te2O6X2 (M = Sr, Ba; X = Cl, Br) have been prepared as polycrystalline powders and/or in the form of single crystals. All compounds crystallize in the cubic space group Fd (3) m with cell parameters a = 15.9351(4) A for Sr3Te2O 6Cl2 (single-crystal X-ray data), 16.052(5) A for Sr3Te2O6Br2 (powder X-ray data), 16.688(2) A for Ba3Te2O6Cl2 (single-crystal X-ray data) and 16.8072(3) A for Ba3Te 2O6Br1.64Cl0.36 (single-crystal X-ray data). The results of the crystal structure analyses reveal a rigid (3)[M3Te2O6]2+ framework which can be described as being composed of regular octahedra of two types of chemically non-bonded M6 octahedra that are capped by trigonal pyramidal [TeO3] anions located above every second face of one of the M 6 octahedra. The halide X- anions are situated in the voids of the [M3Te2O6]2+ framework. Dependent on the nature of the halogen, the anions show various kinds of occupational disorder which eventually led to a revision of the previous structure model of Ba3Te2O6Cl2. A comparative discussion with other structures of general formula M 3Ch2O6X2 (M = divalent metal; Ch = Te, Se; X = Cl, Br) is presented. Copyright
- Stoeger, Berthold,Weil, Matthias,Silich, Konstantin A.,Olenev, Andrey V.,Berdonosov, Peter S.,Dolgikh, Valery A.
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p. 1322 - 1329
(2011/11/05)
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- On the chemical vapor transport of ternary transition metal- and earth
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The chemical vapor transport of transition metal tungstates MWO4 (M=Mn, Co, Ni, Cu, Zn, Cd) was investigated in dependence on mean transport temperature (923 K to 1223 K) and amount of transport agent Cl2. All tungstates migrate in a temperature gradient ΕT = 100 K from the region of higher temperature to the lower temperature with migration rates of 0.5 to 8 mg/h depending on experimental conditions. The transport behaviour was determined by continuous measurement of mass change during the transport experiments. The results were compared to thermo chemical calculations and the influence of moisture content discussed in detail. MgWO4 migrates under the influence of Cl2 in a temperature gradient 1273 K to 1173 K (migration rate 0.7 mg/h), CaWO4 and SrWO4 in a temperature gradient 1423 K to 1323 K (migration rate 0.1 mg/h).
- Steiner, Udo
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p. 1706 - 1714
(2008/10/09)
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- Ammonia Absorption on Alkaline Earth Halides as Ammonia Separation and Storage Procedure
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For the low pressure ammonia synthesis (~1 MPa, 573-623 K), 40-80 kPa of ammonia produced must be separated. For this purpose, the absorption behavior of five kinds of alkaline earth metal halides (MgCl2, CaCl2, CaBr2, SrC
- Liu, Chun Yi,Aika, Ken-Ichi
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p. 123 - 131
(2007/10/03)
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- Dentifrice-compatible silica particulates
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Novel silica particulates especially adapted for formulation to dentifrice compositions exhibit unique physical and chemical properties. In one embodiment, silica particulates have a unique surface chemistry as to be at least 50% compatible with zinc values, and have a number of OH functions, expressed as OH/nm2, of at most 15 and a zero charge point (PZC) of from 3 to 6.5. In a second embodiment, particulates have a surface chemistry as to be at least 65%, and preferably at least 90% compatible with guanidine values, notably chlorhexidine, and acidity function thereof, Ho, of at least 3.3. In a third embodiment, silica particulates are compatible with organic amines, and have a pH, in aqueous suspension, which varies according to the equations pH≤7.5-0.7 log(C) and pH≥5.0-0.5 log(C) and which also varies as a function of the electrical conductivity thereof, according to the equations pH≤8.5-0.4 log(D) and pH≥7.0-0.6 log(D) wherein (C) represents the weight concentration of said silica suspension, expressed % SiO2 and (D) represents the electrical conductivity of such aqueous silica suspension expressed in microsiemens*cm-1. In a fourth embodiment, novel silica particulates are compatible with such metal cations as zinc, tin, strontium, and the like, as well as with the fluorides, and have a unique surface chemistry such that the number of OH- functions thereof, expressed in OH- /nm2, is equal to or less than 10, and also have a zero charge point (ZCP) ranging from 3 to 6.5 and a pH, in aqueous suspension, which varies as a function of the electrical conductivity thereof according to the equation pH=b-a log (D) in which a is a constant equal to or less than 0.6; b is a constant equal to or less than 8.5; and (D) represents the electrical conductivity of such aqueous silica suspension, expressed in microsiemens*cm-1
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- Enthalpies of Dissolution of Strontium and Barium Chlorides in Water and in Dimethylsulphoxide-Water and Propene Carbonate-Water Mixtures
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The enthalpies of dissolution of SrCl2 and BaCl2 in water and in dimethylsulphoxide (14.83 and 49.66 wt.percent)-water and propene carbonate (9.65 and 15.91 wt.percent)-water mixtures have been measured at 298.15 K.The enthalpy of dissolution of the salts in these solvents at infinite dilution has been calculated.
- Monaenkova, A. S.,Alekseev, G. I.,Vorob'ev, A. F.
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p. 1323 - 1325
(2007/10/02)
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