scholarly journals PRELIMINARY RESULTS UPON CRYSTALLIZATION OF THE CALCITE-SPHEROCOBALTITE SOLID SOLUTION

2007 ◽  
Vol 40 (2) ◽  
pp. 829
Author(s):  
D. Katsikopoulos ◽  
A. Gonzälez-Fernändez ◽  
M. Prieto
Keyword(s):  
Solid Solution ◽  
Solid Phase ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Average Value ◽  
Cobalt Carbonate ◽  
High Supersaturation ◽  
Volume Of Mixing ◽  
Cell Volumes ◽  
Excess Volume Of Mixing

The (Ca,Co)C03-H20 system was studied at 25 °C using both precipitation experiments and crystallization in silica gel in order to examine the thermodynamic properties and crystallization of the solid solution. Near the CaC03 endmember, unit cell parameters and volume of the solid phase show an almost linear variation, while near the C0CO3 endmember, the growth of a phase of low crystallinity prevented those calculations. A detailed Fourier Transform Infrared Spectroscopy (FTIR) assigned this phase to a cobalt carbonate hydrate (CoCO}nH20). The fact that cell volumes are plotted above the line that corresponds to the theoretical cell volumes of the two endmembers, indicates positive value of excess volume of mixing (VE), and consequently a non-ideal solid solution. Nucleation under conditions of high supersaturation in gels showed that in all the cases the degree of cobalt incorporation in crystals was low with an average value of cobalt mole fraction (XC0CO3) around 0.03 while -even in the Co-rich zones- this value never exceeded the upper limit of 0.2. Crystal morphologies also exhibited a wide variety of forms as a function of aqueous phase composition.

The solid solution TbNiIn1−x Ga x

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Myroslava Horiacha ◽  
Galyna Nychyporuk ◽  
Rainer Pöttgen ◽  
Vasyl Zaremba
Keyword(s):  
Solid Solution ◽  
Unit Cell ◽  
Type Structure ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Structure Space ◽  
Arc Melting

Abstract Phase formation in the solid solution TbNiIn1−x Ga x at 873 K was investigated in the full concentration range by means of powder X-ray diffraction and EDX analysis. The samples were synthesized by arc-melting of the pure metals with subsequent annealing at 873 K for one month. The influence of the substitution of indium by gallium on the type of structure and solubility was studied. The solubility ranges have been determined and changes of the unit cell parameters were calculated on the basis of powder X-ray diffraction data: TbNiIn1–0.4Ga0–0.6 (ZrNiAl-type structure, space group P 6 ‾ 2 m $P‾{6}2m$ , a = 0.74461(8)–0.72711(17) and c = 0.37976(5)–0.37469(8) nm); TbNiIn0.2–0Ga0.8–1.0 (TiNiSi-type structure, space group Pnma, а = 0.68950(11)–0.68830(12), b = 0.43053(9)–0.42974(6), с = 0.74186(10)–0.73486(13) nm). The crystal structures of TbNiGa (TiNiSi type, Pnma, a = 0.69140(5), b = 0.43047(7), c = 0.73553(8) nm, wR2=0.0414, 525 F 2 values, 21 variables), TbNiIn0.83(1)Ga0.17(1) (ZrNiAl type, P 6 ‾ 2 m $P‾{6}2m$ , a = 0.74043(6), c = 0.37789(3) nm, wR2 = 0.0293, 322 F 2 values, 16 variables) and TbNiIn0.12(2)Ga0.88(2) (TiNiSi type, Pnma, a = 0.69124(6), b = 0.43134(9), c = 0.74232(11) nm, wR2 = 0.0495, 516 F 2 values, 21 variables) have been determined. The characteristics of the solid solutions and the variations of the unit cell parameters are briefly discussed.

Neutron Powder Diffraction Investigation of Pd2.7Ni0.3P0.94

2004 ◽  
Vol 443-444 ◽  
pp. 353-356
Author(s):  
M. Vennström ◽  
Y. Andersson
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Powder Diffraction ◽  
Rietveld Method ◽  
Neutron Powder Diffraction ◽  
Unit Cell ◽  
Type Structure ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Method Show

Pd3P, which crystallises in the cementite, Fe3C-type structure, forms a solid solution with nickel. The crystal structure contains two crystallographically different palladium sites (8d and 4c). Refinements of neutron powder diffraction intensities using the Rietveld method show that all nickel atoms occupy the eight-fold position. The unit cell parameters were refined to a=5.7812(4) Å, b=7.4756(6) Å and c=5.1376(4) Å, for Pd2.7Ni0.3P0.94.

Structure Studies of Electrodeposited Ni-Mo Alloys with Polymers after Annealing

2007 ◽  
Vol 130 ◽  
pp. 97-100 ◽  
Author(s):  
Małgorzata Karolus ◽  
Edward Rówiński ◽  
Eugeniusz Łągiewka
Keyword(s):  
Solid Solution ◽  
Steel Substrate ◽  
Argon Atmosphere ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Air Atmosphere ◽  
Diffraction Patterns

Electrolytical layers of Ni-Mo alloys with polypyrrole, polytiofene and polyethylene were deposited on steel substrate (St3S, 4 cm2). After structural analyses of as quenched samples performed by X-ray diffraction it was noticed that the solid solution of Mo in Ni is observed. After annealing in an argon atmosphere the solid solution of Mo in Ni is becomeing more stable and crystalites are growing to the size of 200 – 300 Å. After annealing in an air atmosphere X-ray diffraction patterns show presence of phases: NiO, MoO, NiCO3, Mo2N. The unit cell parameters of solid solution after annealing are smaller than parameters of as quenched samples what means that the solid solution has been decomposing.

Subsolidus phase relations of the Dy-Fe-Al system

2011 ◽  
Vol 26 (1) ◽  
pp. 9-15
Author(s):  
Y. Q. Chen ◽  
J. K. Liang ◽  
J. Luo ◽  
J. B. Li ◽  
G. H. Rao
Keyword(s):  
Solid Solution ◽  
Phase Relations ◽  
Unit Cell Parameters ◽  
Subsolidus Phase ◽  
X Ray ◽  
Cell Parameters ◽  
Ternary Compounds ◽  
Al Content ◽  
Three Phase ◽  
Binary Compounds

The subsolidus phase relations of the Dy-Fe-Al system have been investigated by means of X-ray powder diffraction. There are 5 ternary compounds, 10 binary compounds, and 21 three-phase regions in this system. The solid-solution regions of Dy(Fe1−xAlx)2, DyFe3−xAlx, Dy2(Fe1−xAlx)17, and DyFe12−xAlx have been determined based on the dependence of their unit-cell parameters on the Al content.

Unit-cell parameters for scapolite solid solutions and a discontinuity at Me75, ideally NaCa3[Al5Si7O24](CO3)

2013 ◽  
Vol 28 (4) ◽  
pp. 269-275
Author(s):  
Sytle M. Antao
Keyword(s):  
Solid Solution ◽  
Unit Cell Volume ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Unit Cell ◽  
Formula Unit ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters

Twenty-seven scapolite samples from various localities and with compositions between Me6–93 were obtained using electron microprobe analysis (EMPA). Their unit-cell parameters were obtained using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data and Rietveld structure refinements using space group P42/n. The EMPA data show the well-known discontinuity at Me75. In addition, the unit-cell parameters, especially c, show a discontinuity at Me75 (=five Al atoms per formula unit, apfu), ideally NaCa3[Al5Si7O24](CO3), where the scapolite solid solution is divided into two (Me% = [Ca/(Ca + Na + K)] × 100). A maximum c parameter value occurs at Me37.5 (=four Al apfu ideally), where complete Al–Si, Na–Ca, and Cl–CO3 order occurs. The unit-cell volume, V, varies smoothly with Me% and Al apfu across the series.

Exhaustive indexing of triclinic powder diffraction patterns with known unit cell parameters

1994 ◽  
Vol 9 (2) ◽  
pp. 87-92 ◽  
Author(s):  
Ludo K. Frevel
Keyword(s):  
Powder Diffraction ◽  
Interplanar Spacing ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Triclinic Phase ◽  
Diffraction Patterns ◽  
Cell Volumes ◽  
Novel Algorithm

A novel algorithm has been developed for obtaining directly the applicable indices hkl for any interplanar spacing, dobs±Δdobs, of a triclinic phase with known unit cell parameters. This method is particularly useful for indexing back reflections for triclinic phases with unit cell volumes greater than 500 Å3.

Unit Cell Parameters and Densities of the Solid Solution Pd(B)

2000 ◽  
Vol 321-324 ◽  
pp. 604-609 ◽  
Author(s):  
M. Beck ◽  
M. Ellner ◽  
Eric J. Mittemeijer
Keyword(s):  
Solid Solution ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Cell Parameters

scholarly journals Crystal structures and comparisons of potassium rare-earth molybdates KRE(MoO4)2 (RE = Tb, Dy, Ho, Er, Yb, and Lu)

2020 ◽  
Vol 76 (12) ◽  
pp. 1871-1875
Author(s):  
Saehwa Chong ◽  
Samuel Perry ◽  
Brian J. Riley ◽  
Zayne J. Nelson
Keyword(s):  
Rare Earth ◽  
Crystal Structures ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Using Data ◽  
Cell Volumes ◽  
Rare Earth Molybdates

Six potassium rare-earth molybdates KRE(MoO4)2 (RE = Tb, Dy, Ho, Er, Yb, and Lu) were synthesized by flux-assisted growth in K2Mo3O10. The crystal structures were determined using single-crystal X-ray diffraction data. The synthesized molybdates crystallize with the orthorhombic Pbcn space group (No. 60). Trendlines for unit-cell parameters were calculated using data from the current study. The unit-cell parameters a and c increase linearly whereas b decreases with larger RE cations, based on crystal radii. The unit-cell volumes increase linearly and the densities decrease linearly with larger RE cations. The average distances between the RE cations and the nearest O atoms increase with larger cations whereas the average distances of Mo—O and K—O do not show specific trends.

scholarly journals Solid solution formation in the metatorbernite–metazeunerite system (Cu(UO 2 ) 2 (PO 4 ) 2− x (AsO 4 ) x . n H 2 O) and their stability under conditions of variable temperature

2019 ◽  
Vol 377 (2147) ◽  
pp. 20180242 ◽  
Author(s):  
Joanna Kulaszewska ◽  
Sandra Dann ◽  
Peter Warwick ◽  
Caroline Kirk
Keyword(s):  
Solid Solution ◽  
Low Temperatures ◽  
Variable Temperature ◽  
Unit Cell ◽  
Tetragonal Symmetry ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Mineral Phases

Mineral phases which can be thought of as members of a metatorbernite–metazeunerite solid solution (Cu(UO 2 ) 2 (PO 4 ) 2− x (AsO 4 ) x .8H 2 O have been identified in radioactive samples from spoil heaps at the uranium mine site in South Terras, Cornwall (grid reference SW935523) . A complete solid solution (0 <  x  < 2) was synthesized by precipitation from solution using uranium (VI) nitrate and copper (II) chloride and phosphoric acid/arsenic acid in the appropriate molar proportions. Refined unit cell parameters determined by Pawley fitting of powder X-ray diffraction data showed a linear variation in the a unit cell parameter according to Vegard's Law, allowing the composition of the natural mineral phases found at South Terras to be determined from measurement of their unit cell parameters. High-resolution variable-temperature synchrotron powder X-ray diffraction studies were carried out at the Diamond Light Source on three members of this solid solution ( x  = 0, 1, 2) and showed different structural behaviour as a function of composition and temperature. Metatorbenite ( x  = 0) retains its tetragonal symmetry at low temperatures and dehydrates to an amorphous phase at 473 K, whereas metazeunrite ( x  = 2) transforms to an orthorhombic phase at low temperatures, regains its tetragonal symmetry on heating to 323 K and undergoes a further transition to an, as yet, unidentified phase at 473 K. This article is part of the theme issue ‘Fifty years of synchrotron science: achievements and opportunities’.

Thermal expansion of cancrinite

1996 ◽  
Vol 60 (403) ◽  
pp. 949-956 ◽  
Author(s):  
Ishmael Hassan
Keyword(s):  
Thermal Expansion ◽  
Room Temperature ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
Expansion Mechanism ◽  
Expansion Coefficients ◽  
Cell Volumes

AbstractThermal expansion coefficients were measured for a cancrinite from Bancroft, Ontario, Canada. Measurements of cell parameters and unit-cell volumes were obtained at room temperature and at heating intervals of 50°C over the temperature range from 50 to 1400°C. The unit-cell parameters for cancrinite increase non-linearly with temperature up to 1200°C and shortly thereafter, the mineral melted. The c parameter increases more rapidly than the a parameter, and the c/a ratio increases linearly with temperature. A plausible thermal expansion mechanism for cancrinite, which is based on the framework expansion that occurs as a function of cavity content, is presented. In the thermal expansion of cancrinite, the short Na-H2O in the H2O-Na—H2O chain expands to form equal distances to the two H2O molecules in the chain. This causes the Na atoms to move towards the plane of the six-membered rings and forces the tetrahedra to rotate and the rings become more planar. The Na atoms then form bonds to all six (O1 and O2) oxygen atoms in a ring; the Na-O1 bonds become shorter and the Na-O2 bonds become longer. These effects cause an increase in both a and c, and thus an increase in the c/a ratio. A similar thermal expansion mechanism operates in the sodalite-group minerals where the six-membered rings and Na-Cl bond are involved.

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