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1.
Evidence for the existence of primitive life forms such as lichens and fungi can be based upon the formation of oxalates.
These oxalates form as a film like deposit on rocks and other host matrices. The anhydrous oxalate mineral moolooite CuC2O4 as the natural copper(II) oxalate mineral is a classic example. Another example of a natural oxalate is the mineral wheatleyite
Na2Cu2+(C2O4)2·2H2O.
High resolution thermogravimetry coupled to evolved gas mass spectrometry shows decomposition of wheatleyite at 255°C. Two
higher temperature mass losses are observed at 324 and 349°C. Higher temperature mass losses are observed at 819, 833 and
857°C. These mass losses as confirmed by mass spectrometry are attributed to the decomposition of tennerite CuO. In comparison
the thermal decomposition of moolooite takes place at 260°C. Evolved gas mass spectrometry for moolooite shows the gas lost
at this temperature is carbon dioxide. No water evolution was observed, thus indicating the moolooite is the anhydrous copper(II)
oxalate as compared to the synthetic compound which is the dihydrate. 相似文献
2.
V. N. Serezhkin A. G. Verevkin O. P. Smirnov V. P. Plakhtii 《Russian Journal of Inorganic Chemistry》2010,55(10):1600-1606
A powder of deuterated rubidium diselenatouranylate dihydrate Rb2UO2(SeO4)2 · 2D2O has been studied by neutron diffraction. The compound is orthorhombic, space group Pna21, with the following unit cell parameters: a = 13.654(2) Å, b = 11.863(2) Å, c = 7.625(1) Å, Z = 4, R F = 3.77, R I = 6.12, and χ2 = 2.21. Basic structure units are [UO2(SeO4)2 · D2O]2? layers belonging to the AB 2 2 M1 crystal-chemical group (A = UO 2 2+ , B2 = SeO 4 2? , M1 = D2O) of uranyl complexes. The hydrogen atoms if the water molecules involved in the layer form intralayer hydrogen bonds with the terminal oxygen atoms of selenate ions. The outer-sphere water molecules are coordinated to the rubidium ions and are involved in hydrogen bonding with oxygen atoms of neighboring [UO2(SeO4)2 · D2O]2? layers. 相似文献
3.
M. Niyaz Ahamad Rahul Vaish K. B. R. Varma 《Journal of Thermal Analysis and Calorimetry》2011,105(1):239-243
Glasses of the composition 2TeO2–V2O5 were fabricated via the conventional melt-quenching technique. The amorphous and the glassy nature of the as-quenched samples
were confirmed by X-ray powder diffraction (XRD) and differential scanning calorimetry (DSC), respectively. The glass transition
and crystallization parameters were evaluated under non-isothermal conditions using DSC. X-ray diffraction studies confirmed
the presence of partially oriented crystallites in the heat-treated glasses. Kauzmann temperature (lower bound for the kinetically
observed glass transition) was deduced from the heating rate dependent glass transition and crystallization temperatures. 相似文献
4.
Phase and conversion equilibria in the quaternary reciprocal water–salt system 2HCOONa + CaCl2 ? (HCOO)2Ca + 2NaCl–H2O at 25°C were studied for the first time to determine the concentration parameters of the production of calcium formate from sodium formate. 相似文献
5.
G. V. Lavrova N. V. Bulina V. S. Min’kov A. A. Matvienko 《Russian Journal of Inorganic Chemistry》2016,61(3):284-290
The thermal transformations of disubstituted cesium orthophosphate crystal hydrate under heating in air up to 400°C have been studied. The dehydration process occurs in two stages with the loss of 0.6 water molecules at 60?100°C and 1.4 water molecules at 100?160°C. Anhydrous Cs2HPO4 is stable up to 300°C and is completely converted into cesium pyrophosphate Cs4P2O7 at 330°C. The structure of Cs2HPO4 · 2H2O has been determined. The compound crystallizes in monoclinic space group P21/c and has the unit cell parameters a = 7.4761(5) Å, b = 14.2125(8) Å, c = 7.9603(6) Å, β = 116.914(5)°, V = 754.20(9) Å3, and Z = 4 at?123°C. An earlier unknown polymorph of Cs4P2O7 has been found. According to X-ray powder diffraction data, hexagonal space group Р63 has been proposed for the formed pyrophosphate. 相似文献
6.
Y. I. Jafarov A. M. Mirzoeva M. B. Babanly 《Russian Journal of Inorganic Chemistry》2008,53(1):146-152
Phase equilibria in the reciprocal system 3Tl2S + Sb2Se3 ? 3Tl2Se + Sb2S3 are investigated by DTA, X-ray powder diffraction, and emf measurements. Some polythermal sections, the isothermal section of the phase diagram at 400K, and the liquidus-surface projection for this system are constructed. The types and coordinates of invariant and univariant equilibria are determined. It is shown that the system is non-diagonal. Broad regions of solid solutions are found on the basis of the binary compounds Tl2S and Tl2Se and along the boundary system Sb2S3-Sb2Se3 and the sections Tl3SbS3-Tl3SbSe3, TlSbS2-TlSbSe2, and TlSb3S5-TlSb3Se5 of the phase diagram. 相似文献
7.
V. D. Živanović S. R. Grujić M. B. Tošić N. S. Blagojević J. D. Nikolić 《Journal of Thermal Analysis and Calorimetry》2009,96(2):427-432
The crystallization of K2O·TiO2·3GeO2 glass under non-isothermal condition was studied. In powdered glass with particle sizes less than 0.15 mm, surface crystallization
was dominant and an activation energy of crystal growth of E
a,s=327±50 kJ mol−1 was calculated. In the size range 0.15 to 0.45 mm, both surface and volume crystallization occurred. For particle sizes >0.45
mm, volume crystallization dominated with spherulitic morphology of the crystals growth and E
a,v=359±64 kJ mol−1 was calculated. 相似文献
8.
P. P. Fedorov V. K. Goncharuk I. G. Maslennikova I. A. Telin T. Yu. Glazunova 《Russian Journal of Inorganic Chemistry》2016,61(2):239-242
A phase diagram of the PbF2–SnF2 system has been studied by differential thermal analysis and X-ray powder diffraction. The system forms Pb1–хSnхF2 (х ≤ 0.33) solid solution and three compounds. Pb2SnF6 decomposes in solid state by a peritectoid reaction at 350°С; Pb3Sn2F10 and PbSnF4 melt by peritectic reactions at 565 and 380°С, respectively. The eutectic coordinates are 180°С, 90 mol % SnF2. 相似文献
9.
V. G. Ponomareva I. N. Bagryantseva G. V. Lavrova 《Russian Journal of Electrochemistry》2017,53(6):636-640
The Cs2HPO4 · 2H2O single crystals synthesized from an aqueous solution containing equimolar amounts of H3PO4 and Cs2CO3 were studied by impedance and IR spectroscopy, X-ray diffraction analysis, and differential scanning calorimetry (DSC). The IR spectra were analyzed in accordance with the structural data, and the absorption bands were assigned. The proton conductivity was studied at temperatures in the range 20–250°C. The conductivity of dehydrated Cs2HPO4 was low, ~10–5–10–9 S cm–1 at 90–250°C with an activation energy of conductivity E a = 1.1 eV at 130–250°C. The processes determining the character of the temperature dependence of conductivity were consistent with the DSC and thermogravimetry data. According to these data, dehydration of the crystalline hydrate Cs2HPO4 · 2H2O starts at 60°C and occurs in three stages, forming Cs2HPO4 · 1.5H2O below 100°C; anhydrous Cs2HPO4 at t > 160°C, which is stable up to 300°C; and Cs4P2O7 above 330°C. 相似文献
10.
L. B. Serezhkina E. V. Peresypkina A. V. Virovets I. V. Medrish D. V. Pushkin 《Russian Journal of Inorganic Chemistry》2009,54(10):1577-1580
Single crystals of Cs[(UO2)2(C2O4)2(OH)] · H2O were synthesized and structurally studied using X-ray diffraction. The compound crystallizes in monoclinic space group P21/m, Z = 2, with the unit cell parameters a = 5.5032(4) Å, b = 13.5577(8) Å, c = 9.5859(8) Å, β = 97.012(3)°, V = 709.86(9) Å3, R = 0.0444. The main building units of crystals are [(UO2)2(C2O4)2(OH)]? layers of the A2K 2 02 M2 (A = UO 2 2+ , K02 = C2O 4 2? , and M2 = OH?) crystal-chemical family. Uranium-containing layers are linked into a three-dimensional framework via electrostatic interactions with outer-sphere cations and hydrogen bonds with water molecules. 相似文献
11.
Zh. V. Akhmerkina E. V. Peresypkina A. V. Virovets L. B. Serezhkina 《Russian Journal of Inorganic Chemistry》2008,53(9):1396-1400
Single crystals of Ba3[UO2(C2O4)2(NCS)]2 · 9H2O are synthesized and studied by X-ray diffraction. The crystals are orthorhombic, space group Fddd, Z = 16, and the unit cell parameters are a = 16.253(3) Å, b = 22.245(3) Å, c = 39.031(6) Å. The main crystal structural units are mononuclear complex groups [UO2(C2O4)2NCS]3? of the crystal-chemical family (AB 2 01 M1 (A = UO 2 2+ , B01 = C2O 4 2? , M1 = NCS?) of the uranyl complexes linked into a three-dimensional framework by electrostatic interactions and hydrogen bonds involving oxalate ions and water molecules. 相似文献
12.
P. G. Gagarin A. V. Tyurin V. N. Gus’kov A. V. Khoroshilov K. S. Gavrichev 《Russian Journal of Inorganic Chemistry》2018,63(11):1478-1483
The isobaric heat capacity of Tm2O3 · 2ZrO2 solid solution was measured by adiabatic calorimetry and differential scanning calorimetry (DSC), and smoothed values of the enthalpy changes, entropy, and reduced Gibbs free energy in the temperature range 8–1200 K were calculated. Thermal expansion was studied by X-ray diffraction in the temperature range 298–1173 K. 相似文献
13.
Dong-Yong Chung Heui-Seung Seo Jae-Won Lee Han-Beom Yang Eil-Hee Lee Kwang-Wook Kim 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(1):123-129
A feasibility and basic study to find a possibility to develop such a process for recovering U alone from spent fuel by using
the methods of an oxidative leaching and a precipitation of U in high alkaline carbonate media was newly suggested with the
characteristics of a highly enhanced proliferation-resistance and more environmental friendliness. This study has focused
on the examination of an oxidative leaching of uranium from SIMFUEL powders contained 16 elements (U, Ce, Gd, La, Nd, Pr,
Sm, Eu, Y, Mo, Pd, Ru, Zr, Ba, Sr, and Te) using a Na2CO3 solution with hydrogen peroxide. U3O8 was dissolved more rapidly than UO2 in a carbonate solution. However, in the presence of H2O2, we can find out that the leaching rates of the reduced SIMFUEL powder are faster than the oxidized SIMFUEL powder. In carbonate
solutions with hydrogen peroxide, uranium oxides were dissolved in the form of uranyl peroxo-carbonato complexes. UO2(O2)
x
(CO3)
y
2−2x−2y
, where x/y has 1/2, 2/1. 相似文献
14.
Shi-hua Sang Xiao-ping Li Da-wei Li Rui-zhi Cui Cui Wei 《Russian Journal of Inorganic Chemistry》2018,63(12):1644-1650
Solid-liquid equilibria in the quaternary systems KCl–MgCl2–SrCl2–H2O and NaCl–KCl–SrCl2–H2O at 348 K were measured by the isothermal solution saturation method. The composition of the equilibrium solid phase, solubilities of salts, and densities of saturated solution in the two systems were determined. Phase diagrams, water content diagrams and solution density diagrams of quaternary systems were plotted according to experimental data. The phase diagram of the quaternary system NaCl–KCl–SrCl2–H2O has one invariant point, three univariant curves as the boundary of NaCl, KCl and SrCl2 · 2H2O. This phase diagrams were simple co-saturation type without complex salt and solid solution. For the quaternary system KCl–MgCl2–SrCl2–H2O, one complex salt KCl · MgCl2 · 6H2O (Car) had been found in this system, consisted of five univariant curves, two invariant points and four crystallization regions of MgCl2 · 6H2O (Bis), KCl, SrCl2 · 2H2O and KCl · MgCl2 · 6H2O. And the densities transformation rules were simply discussed. Simultaneously, the solubilities and densities data in invariant point of the quaternary system NaCl–KCl–SrCl2–H2O had been compared with the experimental data of previous researchers. 相似文献
15.
R. S. Mirzoev R. A. Shetov M. Kh. Ligidov R. M. El’mesova 《Russian Journal of Inorganic Chemistry》2010,55(1):96-102
Phase formation in the Na2MoO4-K2MoO4-H2O system was studied at 25°C. Two incongruently saturating complex phases are formed in this system: Na3K(MoO4)2 · 9H2O and NaK3(MoO4)2. The densities, refractive indices, and dynamic viscosities of saturated solutions of the system were determined; molar volume
and ionic strength isotherms were calculated. A correlation relation was found between solubility and solution properties
in the system. The indicated double salts were recovered and characterized using chemical analysis, powder X-ray diffraction,
complex thermal analysis, and IR spectroscopy. 相似文献
16.
The dependence of solid phase composition on the main parameters of the interaction in the CoSO4-K4P2O7-H2O system was studied. The synthesis conditions were determined and a crystalline cobalt(II) diphosphat of the composition
Co2P2O7 · 6H2O was synthesized. Its thermal properties were studied. The composition and the intervals, wherein the thermally stable products
of partial and complete dehydration of Co2P2O7 · 6H2O are formed, were specified. The final heat treatment product, anhydrous α-Co2P2O7, was identified and a sequence of the solid phase thermal transformations accompanying its formation was established. 相似文献
17.
A quaternary super-ion-conducting system, 20CdI2 − 80[xAg2O − y(0.7V2O5 − 0.3B2O3)] where 1 ≤ x/y ≤ 3, has been prepared by melt quenching technique. The electrical conductivity measured was the order of 10−4 S/cm at room temperature. The values of silver-ion transport number obtained by electromotive force technique are nearly
unity. The thermoelectric power and electrochemical studies were done on the CdI2–Ag2O–V2O5–B2O3 system. The discharge and polarization characteristics were examined for different cathodes to evaluate the utility of these
cells as power sources for low energy applications. 相似文献
18.
19.
Baoling Wang Liuzheng Sun Haidong Ju Shilong Zhao Degang Deng Huanping Wang Shiqing Xu 《Journal of Sol-Gel Science and Technology》2009,50(3):368-371
CaAl2Si2O8: Eu2+, Mn2+ phosphors have been prepared by a sol–gel method. X-ray diffractometer, spectrofluorometer and UV–Vis spectrometer were used
to characterize structural and optical properties of the samples. The results indicate that anorthite (CaAl2Si2O8) directly crystallizes at 1000 °C in the sol–gel process. CaAl2Si2O8: Eu2+, Mn2+ phosphors show two emission bands excited by ultraviolet light. Blue (around 415 nm) and yellow (around 575 nm) emissions
originate from Eu2+ and Mn2+, respectively. With appropriate tuning of Mn2+ content, CaAl2Si2O8: Eu2+, Mn2+ phosphors exhibit different hues and relative color temperatures. 相似文献
20.
G. B. Andreev M. Yu. Antipin N. A. Budantseva N. N. Krot 《Russian Journal of Coordination Chemistry》2005,31(11):800-803
A new neptunium(V) complex [(NpO2)2(CH3COO)2(H2O)] ? 2H2O was synthesized and its crystal structure was determined. The unit cell parameters are: a = 24.007(10) Å, b = 6.779(3) Å, c = 8.076(3) Å, space group Pnma, Z = 4, V = 1314.2(9) Å3, R = 0.049, wR(F2) = 0.105. The crystal structure of the compound is composed of neutral [(NpO2)2(CH3COO)2(H2O)] layers and molecules of the water of crystallization. Each of the crystallographically independent neptunoyl ions performs a bidentate function thus forming a composite system of cation-cation bonds. 相似文献