scholarly journals New triple molybdate and tungstate Na5Rb7Sc2(XO4)9 (X = Mo, W)

2021 ◽  
Vol 8 (4) ◽  
pp. 20218412
Author(s):  
Tatyana S. Spiridonova ◽  
Aleksandra A. Savina ◽  
Evgeniy V. Kovtunets ◽  
Elena G. Khaikina
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Rietveld Method ◽  
Ceramic Technology ◽  
Chemical Transformations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Triple Molybdate ◽  
High Thermal Expansion ◽  
New Compounds

New compounds of the composition Na5Rb7Sc2(XO4)9 (X = Mo, W) were obtained via the ceramic technology. The sequences of chemical transformations occurring during the formation of these compounds were established, and their primary characterization was performed. Both Na5Rb7Sc2(XO4)9 (X = Mo, W) were found to melt incongruently at 857 K (X = Mo) and 889 K (X = W). They are isostructural to Ag5Rb7Sc2(XO4)9 (X = Mo, W), Na5Cs7Ln2(MoO4)9 (Ln = Tm, Yb, Lu) and crystallize in the trigonal crystal system (sp. gr. R32). The crystal structures were refined with the Rietveld method using the powder X-ray diffraction data. The thermal expansion of Na5Rb7Sc2(WO4)9 was studied by high-temperature powder X-ray diffraction; it was shown that this triple tungstate belongs to high thermal expansion materials.

scholarly journals Synthesis, Structure and Thermophysical Properties of Phosphates MNi0.5Zr1.5(PO4)3 (M = Mg, Ca, Sr)

2010 ◽  
Vol 12 (3,4) ◽  
pp. 241 ◽  
Author(s):  
M.V. Sukhanov ◽  
I.A. Schelokov ◽  
V.I. Pet'kov ◽  
E.R. Gobechiya ◽  
Yu.K. Kabalov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Heat Capacity ◽  
Thermal Expansion ◽  
High Temperature ◽  
Single Phase ◽  
Rietveld Method ◽  
Type Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Expansion Behavior

<p>New phosphates MNi<sub>0.5</sub>Zr<sub>1.5</sub>(PO<sub>4</sub>)<sub>3</sub> (M = Mg, Ca, Sr) were prepared by the precipitating method.<strong><em> </em></strong>Phosphates were characterized using X-ray powder diffraction, IR-spectroscopy and electron microprobe analyses. The crystal structure of phosphates was refined by the Rietveld method. Phosphates CaNi<sub>0.5</sub>Zr<sub>1.5</sub>(PO<sub>4</sub>)<sub>3</sub> and SrNi<sub>0.5</sub>Zr<sub>1.5</sub>(PO<sub>4</sub>)<sub>3</sub> are shown to have been crystallized in the NaZr<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub>-type structure and the phosphate MgNi<sub>0.5</sub>Zr<sub>1.5</sub>(PO<sub>4</sub>)<sub>3 </sub>was obtained as a single-phase with Sc<sub>2</sub>(WO<sub>4</sub>)<sub>3</sub>-type structure. Heat capacity of phosphate CaNi<sub>0.5</sub>Zr<sub>1.5</sub>(PO<sub>4</sub>)<sub>3</sub> was measured in the range 7 – 650 K and increased monotonically over the entire temperature range studied. Thermal expansion of phosphate CaNi<sub>0.5</sub>Zr<sub>1.5</sub>(PO<sub>4</sub>)<sub>3</sub> was studied in the interval 295-1073 K by the high temperature X-ray diffraction. This phosphate is similar to the best low-expansion ceramics, such as zircon, cordierite and silica glass in thermal expansion behavior.</p>

Thermal analysis of rare earth gallates and aluminates

1990 ◽  
Vol 5 (1) ◽  
pp. 183-189 ◽  
Author(s):  
H. M. O'Bryan ◽  
P. K. Gallagher ◽  
G. W. Berkstresser ◽  
C. D. Brandle
Keyword(s):  
Thermal Analysis ◽  
Thermal Expansion ◽  
High Temperature ◽  
Superconducting Films ◽  
Czochralski Technique ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Expansion Matching ◽  
First Order Phase

Dilatometry, high-temperature x-ray diffraction, differential thermal analysis, and differential scanning calorirmetry have been performed on LaGaO3, NdGaO3, PrGaO3, SmAlO3, and LaAlO3 single crystals grown by the Czochralski technique. First order phase transitions have been located at 145°C for LaGaO3 and 785°C for SmAlO3, and ΔH has been measured for the LaGaO3 transition. Second order transitions have been identified for LaGaO3, PrGaO3, NdGaO3, and LaAlO3. The usefulness of these compounds as substrates for high temperature superconducting films is discussed in terms of thermal expansion matching.

scholarly journals Correction: High-temperature X-ray diffraction and thermal expansion of nanocrystalline and coarse-crystalline acanthite α-Ag2S and argentite β-Ag2S

2018 ◽  
Vol 20 (5) ◽  
pp. 3847-3850
Author(s):  
S. I. Sadovnikov ◽  
A. I. Gusev ◽  
A. V. Chukin ◽  
A. A. Rempel
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Chem Phys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phys Chem Chem Phys

Correction for ‘High-temperature X-ray diffraction and thermal expansion of nanocrystalline and coarse-crystalline acanthite α-Ag2S and argentite β-Ag2S’ by S. I. Sadovnikov et al., Phys. Chem. Chem. Phys., 2016, 18, 4617–4626.

Relationship Between Thermal Expansion and Crystal Chemical Parameters in Diborides

1986 ◽  
Vol 30 ◽  
pp. 503-510
Author(s):  
H.A. McKinstry ◽  
Lai Daik Chai ◽  
R.V. Sara ◽  
K.E. Spear
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Zirconium Phosphate ◽  
Hexagonal Structure ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
Chemical Parameters ◽  
X Ray ◽  
Sodium Zirconium ◽  
Sodium Zirconium Phosphate

Thermal expansion is an interesting, ubiquitous and neglected property of materials. Recently, Lenain et al. (1985) and Limaye (1986) have been investigating anisotropy in the low-expansion structures of the sodium zirconium phosphate family. In the hexagonal structure one axis expands while another contracts. In going from the calcium to the strontium analog the anisotropy actually changes sign. A change in anisotropy between CrB2 and TiB2 had been observed by R.V. Sara (1960). The results in Fig. 1 obtained by high temperature x-ray diffraction measurements indicate that for TiB2 the thermal expansion of the c-axis is greater than the expansion of the a-axis, whereas for CrB2 the reverse is true.

Polymorphic transformations and thermal expansion of some modifications in Ag1.5Cu0.5Se and Ag0.4Cu1.6Se

2019 ◽  
Vol 33 (23) ◽  
pp. 1950271 ◽  
Author(s):  
Y. I. Aliyev ◽  
Y. G. Asadov ◽  
A. O. Dashdemirov ◽  
R. D. Aliyeva ◽  
T. G. Naghiyev ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Diffraction Method ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Polymorphic Transformations ◽  
X Ray

The Ag[Formula: see text]Cu[Formula: see text]Se and Ag[Formula: see text]Cu[Formula: see text]Se compounds have been synthesized and grown as single crystals. High-temperature X-ray diffraction method was used to study polymorphic transformations. It is shown that the Ag[Formula: see text]Cu[Formula: see text]Se crystals of high-temperature FCC modification are decomposed into Ag2Se and AgCuSe when the temperature decreases below T = 488 K and Ag[Formula: see text]Cu[Formula: see text]Se is decomposed into Cu2Se and AgCuSe when the temperature decreases below T = 540 K. Transformations in both compounds are reversible. Crystalline parameters are obtained and the temperature dependence of the lattice parameters for each phase is built.

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