The CdO–CdF2 system: X-ray diffractogram, infrared spectrum, and density of CdO•2CdF2

1970 ◽  
Vol 48 (10) ◽  
pp. 1619-1622 ◽  
Author(s):  
P. Ramamurthy ◽  
E. A. Secco

The CdO–CdF2 system has been studied by differential thermal analysis (DTA), X-ray powder diffraction, and infrared spectroscopy.The results show a distinct X-ray diffractogram and infrared spectrum for the CdO–CdF2 mole ratio 1:2, prefused and annealed, suggesting the existence of the compound CdO•2CdF2. The compound undergoes a transformation at 690 °C, characterized by a low heat absorption suggesting an order–disorder phenomenon.

2018 ◽  
Vol 64 (6) ◽  
pp. 548
Author(s):  
Gustavo Marroquin ◽  
Gerzon E. Delgado ◽  
Pedro Grima-Gallardo ◽  
Miguel Quintero

The crystal structure of the quaternary compound CuVInSe3 belonging to the system (CuInSe2)1-x(VSe)x with x= ½, was analyzed using X-ray powder diffraction data. This material was synthesized by the melt and anneal method and crystallizes in the tetragonal space group P2c (Nº 112), with unit cell parameters a = 5.7909(4) Å, c = 11.625(1) Å, V = 389.84(5) Å3. The Rietveld refinement of 25 instrumental and structural variables led to Rexp = 6.6 %, Rp = 8.7 %, Rwp = 8.8 % and S = 1.3 for 4501 step intensities and 153 independent reflections. This compound has a normal adamantane structure and is isostructural with CuFeInSe3. The DTA indicates that this compound melts at 1332 K.


2011 ◽  
Vol 217-218 ◽  
pp. 163-168 ◽  
Author(s):  
Lin Xin Tong ◽  
Jin Hong Li ◽  
Jian Cao

A series of gels with 3Al2O3•2SiO2 were prepared by Sol-gel method and heated at several temperatures for 2 h to synthesize Ti, Fe-doped mullite. The powers were characterized by differential thermal analysis (DSC-TG) and X-ray powder diffraction (XRD). Phase separation was promoted by doping both TiO2 and Fe2O3; with increasing the amount of dopant ions the formation temperature of Si-Al spinel decreased and the formation temperature of mullite increased by TiO2 doping but decreased by Fe2O3 doping. The formation temperature of pure mullite was about 1250-1350 °C.


1971 ◽  
Vol 49 (8) ◽  
pp. 1315-1316 ◽  
Author(s):  
A. N. Campbell ◽  
W. H. W. Wood

The Ag–Ca system has been reinvestigated over the composition range 50–100 atomic % Ca, by differential thermal analysis and high temperature X-ray powder diffraction. Our results are in good agreement with those of Alexander et al. (1) and those of Pascal et al. (2) in the region 50–59 atomic % Ca, but the peritectic claimed by Alexander et al., lying at 50% Ca and 598 °C, appears not to exist, according to our DTA and X-ray results. Here and elsewhere our results substantiate those of Pascal et al. We also find that the compound AgCa3 is formed peritectically, and not congruently as suggested by Alexander et al.


2000 ◽  
Vol 65 (12) ◽  
pp. 891-898 ◽  
Author(s):  
Vladimir Zivanovic ◽  
Nikola Blagojevic ◽  
Snezana Grujic ◽  
Ljiljana Karanovic ◽  
Branislava Bozovic

In this paper the effect of the addition of Li2O on the crystallization behavior of PbO-B2O3-ZnO glass was investigated by the differential thermal analysis (DTA) and X-ray powder diffraction (XRPD) methods. The crystallization ability, as well as the crystalline phases which develop during devitrification of the glass were examined. The results of DTA and XRPD analysis showed that the addition of Li2O varies the sequence of the crystallization as well as the phase composition of the crystalline phase. The glasses with Li2O crystallize at a lower temperature (360?C) with 4Li2O.4ZnO.3B2O3 as the major crystalline phase. The base PbO-B2O3-ZnO glass crystallizes at 480?C with PbO.2ZnO.B2O2 as the major crystalline phase.


Author(s):  
Chengfu Xu ◽  
Zhengfei Gu ◽  
Yongquan Yang ◽  
Dongdong Ma ◽  
Gang Cheng ◽  
...  

Abstract The phase relations in the Ce2Co17-Sm2Co17 system over the whole concentration range have been studied by means of Xray powder diffraction, differential thermal analysis and scanning electron microscopy equipped with energy dispersive Xray spectroscopy. The X-ray powder diffraction results reveal that all the alloys (Ce1-xSmx)2Co17 are similar to the end member of the investigated system, Sm2Co17. It is implied that continuous solid solutions are formed in this system. The lattice parameters and unit cell volumes of (Ce1-xSmx)2Co17 solid solutions increase linearly with x increasing from 0 to 1.0. The occurrence of the polymorphic transformation reaction α-(Ce, Sm)2Co17 = β-(Ce, Sm)2Co17 is confirmed in the Ce2Co17-Sm2Co17 system, but its transition temperature cannot be determined. The differential thermal analysis measurements show that both the decomposition temperature and the Curie temperature of the (Ce1-xSmx)2Co17 alloys increase gradually with increasing Sm content. Based on the X-ray powder diffraction results and differential thermal analysis data, the tentative vertical section of Ce2Co17-Sm2Co17 pseudobinary system has been constructed.


2001 ◽  
Vol 56 (10) ◽  
pp. 997-1002 ◽  
Author(s):  
Chnstian Näther ◽  
Inke Jeß ◽  
Harald Studzinski

The thermal behaviour of the three coordination polymers 2∞poly[CuX(μ-2-methylpyrazine- N,N′)] (X = Cl (I), Br (II)), and 2∞poly[{Cu2l2 (μ-pyrazine-N,N′)2 } · 2-methylpyrazine] (III) was investigated using differential thermal analysis and thermogravimetry (DTA-TG) measurements as well as temperature resolved X-ray powder diffraction in argon and in air. On heating all compounds decompose in two steps. In the first step compound I and II loose one and compound III looses two of the 2-methylpyrazine ligands to form the corresponding 2:1 compounds Cu2Cl2(2 -methylpyrazine) (IV) and 2∞poly[Cu2X2 (μ-2 -methylpyrazine-N,N′)] (X = Br (V), I (VI)). From the experiments there is no evidence for the formation of a 1:1 compound of Cul and 2-methylpyrazine as an intermediate phase during the thermal decomposition. On further heating the 2:1 compounds IV, V and VI transform directly to the corresponding copper(I) halides.


2014 ◽  
Vol 87 ◽  
pp. 126-131
Author(s):  
Stanislav Kurajica ◽  
Emilija Tkalčec ◽  
Vilko Mandić ◽  
Iva Lozić ◽  
Jörg Schmauch

Mullite-gahnite composites with different phase-proportions were prepared using sol-gel process. Crystallization path was determined using differential thermal analysis (DTA). X-ray powder diffraction (XRD) was used to study the crystal phases development. The course of the thermal reactions is dominated by the intermediate formation of two spinel phases. The former phase was attributed to gahnite, while the latter to Al-Si spinel. Zn loading decreases amounts of mullite and α-alumina, while increases gahnite and amorphous phase. The observed microstructure of sintered bodies is characterized by fine gahnite particles distributed among larger mullite grains, which is highly favourable for ceramics with high mechanical requirements.


1968 ◽  
Vol 46 (16) ◽  
pp. 2637-2640 ◽  
Author(s):  
G. E. Cranton ◽  
R. D. Heyding

The phase relationships in the gold/selenium system have been examined using X-ray powder diffraction techniques and differential thermal analysis. Only one stable phase, α-AuSe, is formed. A metastable modification of this compound, β-AuSe, is also formed by reaction of the elements. Both forms are monoclinic:α-AuSe: space group C2, Cm, or C2/m; a = 12.21 ± 2, b = 3.693 ± 4, c = 8.434 ± 6 Å, β = 103.20 ± 3°; cell content, 8(AuSe).β-AuSe: primitive monoclinic (space groups P21 or P21/m are likely); a = 6.27 ± 1, b = 3.668 ± 4, c = 8.35 ± 1 Å, β = 105.95 ± 13°; cell content, 4(AuSe).Both modifications decompose peritectoidally at ca. 400 °C. Gold and selenium form a monotectic at 754 °C at a composition just above 50 at. % selenium; some evidence was obtained for the presence of two liquid phases above the monotectic.Tellurium does not substitute in the AuSe lattice to a detectable extent. However, a ternary phase which includes the composition Au2SeTe is formed. Au2SeTe is primitive orthorhombic with a = 8.924 ± 6, b = 7.56 ± 1, c = 5.741 ± 8 Å. The cell contains 4 formula units. Selenium will substitute for at least 15 at. % of the tellurium atoms in the monoclinic AuTe2 calaverite lattice at ca. 400 °C.


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