X-ray diffractometry studies and lattice parameter calculation on KNO3–NH4NO3 solid solutions

2005 ◽  
Vol 20 (02) ◽  
pp. 101-104 ◽  
Author(s):  
Wen-Ming Chien ◽  
Dhanesh Chandra ◽  
Jennifer Franklin ◽  
Claudia J. Rawn ◽  
Abdel K. Helmy
1965 ◽  
Vol 2 (6) ◽  
pp. 596-621 ◽  
Author(s):  
A. D. Edgar

The extent of melilite solid solutions has been determined for the systems gehlenite–soda melilite, akermanite–soda melilite, and gehlenite–akermanite–soda melilite at 800 °C and 1 000 kg/cm2[Formula: see text] Approximately 50 weight % NaCaAlSi2O7 will form melilite solid solutions with both gehlenite and akermanite but the extent of complete solid solutions in the gehlenite–akermanite–soda melilite system is very limited at this temperature. Lattice parameter determinations of melilite solid solutions indicate that there is a small but significant change in both a and c parameters with increasing soda melilite in the gehlenite–soda melilite system. In the gehlenite–akermanite–soda melilite system, although the range of complete solid solution is very limited, melilites form more than 90% of the products in most compositions and their lattice parameters can be correlated approximately with their bulk compositions, A rapid X-ray method has been developed to determine the approximate compositions of melilites in this system. Comparison is made between the synthetic samples and natural melilites.A reconnaissance of subsolidus phase relations indicates that phase relations are very complex and that only over a very small compositional range can these systems be considered binary or ternary. These studies also indicate that the relations reported by Nurse and Midgley in 1953 should probably be modified. Although the composition NaCaAlSi2O7 does not synthesize only a melilite under the conditions used in this study, it is believed that this is the correct composition of the sodium-bearing end-member.


1961 ◽  
Vol 5 ◽  
pp. 142-152
Author(s):  
Frank L. Chan

AbstractSingle crystals of cadmium sulfide and zinc sulfide have been grown and studied intensively by the Solid State Physics group at the Aeronautical Research Laboratory. The physical phenomena such as reflection, transmission, ultraviolet-excited emission, and electrical resistivity have been observed and characterized on single crystals of these sulfides. Much interest concerning these phenomena has also been centered on single crystals containing both cadmium sulfide and zinc sulfide.For research purposes, mixed crystals as small as a few tenths of 1 mg or less, to 0.5 g of the mixed sulfides, are being prepared. Special chemical methods are required to determine these constituents in them quantitatively. At times, these chemical methods are not applicable, since these methods invariably consume the sample, and, as a result, other observations on the same crystals cannot be performed.Changes in lattice parameter in single crystals of mixed sulfides as compared to pure zinc sulfide or cadmium sulfide provide excellent means for the determination of the percentage of these sulfides. In the X-ray method, single crystals used for the determination of the lattice parameters remain intact. The equipment adopted, procedure used, and the data obtained are illustrated and discussed.In the present study, crystals of cadmium sulfide (greenockite), alpha-zinc sulfide (wurtzite) and solid solutions of these two sulfides having a hexagonal unit cell were used. Since the lattice parameter a0 is found to follow Vegard's law, single-crystal rotation photographs described in this paper were obtained by rotating crystals around the c axis; the lattice parameter was determined with high precision by scanning along the zero-layer line with a microphotometer.


2006 ◽  
Vol 61 (7) ◽  
pp. 916-922 ◽  
Author(s):  
Vera Rührup ◽  
Hans-Dieter Wiemhöfer

The total conductivity of the solid solutions (Ce1−xZrx)0.8Gd0.2O1.9 and (Ce1−xZrx)0.8Y0.2O1.9 was measured in air as a function of temperature (T = 300 °C- 600 °C) and composition (x = 0.0 - 0.9). A deep minimum of the bulk ionic conductivity was found for equal fractions of ceria and zirconia. It indicates enhanced defect association and ordering of the oxygen vacancies around x = 0.5. X-ray analysis (Guinier technique) showed the diffraction pattern of the cubic fluorite structure for all investigated compositions 0 < x < 1. The lattice parameter decreased linearly with increasing zirconia content x.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Durga Sankar Vavilapalli ◽  
Ambrose A. Melvin ◽  
F. Bellarmine ◽  
Ramanjaneyulu Mannam ◽  
Srihari Velaga ◽  
...  

AbstractIdeal sillenite type Bi12FeO20 (BFO) micron sized single crystals have been successfully grown via inexpensive hydrothermal method. The refined single crystal X-ray diffraction data reveals cubic Bi12FeO20 structure with single crystal parameters. Occurrence of rare Fe4+ state is identified via X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The lattice parameter (a) and corresponding molar volume (Vm) of Bi12FeO20 have been measured in the temperature range of 30–700 °C by the X-ray diffraction method. The thermal expansion coefficient (α) 3.93 × 10–5 K−1 was calculated from the measured values of the parameters. Electronic structure and density of states are investigated by first principle calculations. Photoelectrochemical measurements on single crystals with bandgap of 2 eV reveal significant photo response. The photoactivity of as grown crystals were further investigated by degrading organic effluents such as Methylene blue (MB) and Congo red (CR) under natural sunlight. BFO showed photodegradation efficiency about 74.23% and 32.10% for degrading MB and CR respectively. Interesting morphology and microstructure of pointed spearhead like BFO crystals provide a new insight in designing and synthesizing multifunctional single crystals.


Carbon Trends ◽  
2021 ◽  
pp. 100071
Author(s):  
Keith R. Hallam ◽  
James Edward Darnbrough ◽  
Charilaos Paraskevoulakos ◽  
Peter J. Heard ◽  
T. James Marrow ◽  
...  

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 640
Author(s):  
Hideaki Sasaki ◽  
Keisuke Sakamoto ◽  
Masami Mori ◽  
Tatsuaki Sakamoto

CeO2-based solid solutions in which Pd partially substitutes for Ce attract considerable attention, owing to their high catalytic performances. In this study, the solid solution (Ce1−xPdxO2−δ) with a high Pd content (x ~ 0.2) was synthesized through co-precipitation under oxidative conditions using molten nitrate, and its structure and thermal decomposition were examined. The characteristics of the solid solution, such as the change in a lattice constant, inhibition of sintering, and ionic states, were examined using X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), transmission electron microscopy (TEM)−EDS, and X-ray photoelectron spectroscopy (XPS). The synthesis method proposed in this study appears suitable for the easy preparation of CeO2 solid solutions with a high Pd content.


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