Incorporation of Thorium in the Zircon Structure Type through the Th1–xErx(SiO4)1–x(PO4)x Thorite–Xenotime Solid Solution

2016 ◽  
Vol 55 (21) ◽  
pp. 11273-11282 ◽  
Author(s):  
Adel Mesbah ◽  
Nicolas Clavier ◽  
M. Janeth Lozano-Rodriguez ◽  
Stephanie Szenknect ◽  
Nicolas Dacheux
Keyword(s):  
Solid Solution ◽  
Structure Type ◽  
Zircon Structure

scholarly journals Ge0.57Ti0.43O2: a new high-pressure material with rutile-type crystal structure

2018 ◽  
Vol 74 (7) ◽  
pp. 1010-1012 ◽  
Author(s):  
Emil Stoyanov ◽  
Kurt Leinenweber ◽  
Thomas L. Groy ◽  
Abds-Sami Malik
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
High Pressure ◽  
Single Crystals ◽  
Structure Type ◽  
Site Symmetry ◽  
Rutile Structure ◽  
High Pressure And Temperature ◽  
Atom Position ◽  
Type Crystal

Single crystals of a GeO2–TiO2 solid solution with the corresponding composition Ge0.57Ti0.43O2 (germanium titanium tetraoxide) were obtained by devitrification of germania-titania glass at high pressure and temperature. The new compound crystallizes in the rutile structure type (space group P42/mnm), where Ge and Ti share the same position M (site symmetry m.mm), with occupancy values of 0.57 (3) and 0.43 (3), respectively, and one O-atom position (m.2m). The M site is in a sixfold O-atom coordination and, as in the original TiO2 rutile structure, an elongation of the O—M—O bonds along the c-axis direction of the coordination polyhedron and deviation of the angles from 90° lead to a decrease in the coordination symmetry from octahedral to tetragonal. The Ge and Ti atoms are fully disordered in the structure, which indicates that the rutile structure is surprisingly pliant given the differing sizes of the two cations.

Nickel-deficient Stannides Eu2Ni2–xSn5 – Structure, Magnetic Properties, and Mössbauer Spectroscopic Characterization

2009 ◽  
Vol 64 (10) ◽  
pp. 1107-1114 ◽  
Author(s):  
Thomas Harmening ◽  
Matthias Eul ◽  
Rainer Pöttgen
Keyword(s):  
Solid Solution ◽  
Magnetic Properties ◽  
Powder Diffraction ◽  
Spectroscopic Characterization ◽  
Structure Type ◽  
Induction Melting ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Divalent Europium ◽  
Experimental Magnetic Moment

New nickel-deficient stannides Eu2Ni2−xSn5 were synthesized by induction melting of the elements in sealed tantalum tubes. The solid solution was studied by X-ray powder diffraction and two crystal structures were refined on the basis of X-ray diffractometer data: Cmcm, a = 466.03(4), b = 3843.1(8), c = 462.92(9) pm, wR2 = 0.0469, 692 F2 values, 39 variables for Eu2Ni1.49(1)Sn5 and a = 466.11(9), b = 3820.1(8), c = 462.51(9) pm, wR2 = 0.0358, 695 F2 values, 39 variables for Eu2Ni1.35(1)Sn5. This new structure type can be considered as an intergrowth structure of CaBe2Ge2- and CrB-related slabs. The striking structural motifs are nickel-centered square pyramids which are condensed via common corners and edges. The layers of condensed NiSn5 units are separated by the europium atoms. The Ni1 sites within the CaBe2Ge2 slabs show significant defects which leads to split positions for one tin site. Eu2Ni1.50Sn5 shows Curie-Weiss behavior and an experimental magnetic moment of 7.74(1) μB / Eu atom, indicating stable divalent europium, as is also evident from 151Eu Mössbauer spectra. Antiferromagnetic ordering is detected at 3.5 K.

scholarly journals Synthesis, Structural, Electrical Transport and Energetic Characteristics of ZrNi1-хVxSn Solid Solution

2019 ◽  
Vol 20 (3) ◽  
pp. 275-281
Author(s):  
L. Romaka ◽  
Yu. Stadnyk ◽  
V.A. Romaka ◽  
A. Нoryn ◽  
I. Romaniv ◽  
...  
Keyword(s):  
Solid Solution ◽  
Fermi Level ◽  
Electrical Transport ◽  
Energy State ◽  
Structure Type ◽  
Structural Defects ◽  
Simultaneous Generation ◽  
Heusler Phase ◽  
Arc Melting ◽  
Donor And Acceptor

The samples of ZrNi1-хVxSn solid solution (x = 0 – 0.10) based on the ZrNiSn half-Heusler phase (MgAgAs structure type) were synthesized by direct arc-melting with homogenous annealing at 1073 K. The electrokinetic and energy state characteristics of the ZrNi1-хVxSn semiconducting solid solution were investigated in the temperature range T = 80 - 400 K. An analysis of behavior of the electrokinetic and energetic characteristics, in particular, the motion rate of the Fermi level, ΔεF/Δx for ZrNi1-хVxSn, allows to assume about the simultaneous generation of the structural defects of donor and acceptor nature in the crystal. The additional researches are required to establish the mechanisms of donor generation.

Structural Evolution in the Systems TAl3-xGex (T = Zr, Hf)

2019 ◽  
Vol 289 ◽  
pp. 71-76
Author(s):  
Danylo Maryskevych ◽  
Yaroslav O. Tokaychuk ◽  
Roman E. Gladyshevskii
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Crystal Structures ◽  
Structural Evolution ◽  
Structure Type ◽  
Ternary Compounds ◽  
Pearson Symbol ◽  
The Family ◽  
Binary Compounds ◽  
High Temperature Modification

The crystal structures of the binary compounds ZrAl3 and HfAl3 at 600°C belong to the structure type ZrAl3 (Pearson symbol tI16, space group I4/mmm, a = 4.00930(11), c = 17.2718(7) Å for ZrAl3 and a = 3.9849(3), c = 17.1443(15) Å for HfAl3). Substitution of Ge atoms for Al atoms in ZrAl3 and HfAl3 led to the formation of the ternary compounds ZrAl2.52(1)Ge0.48(1) and HfAl2.40(1)Ge0.60(1), respectively, where the latter is probably part of a solid solution extending from the high-temperature modification of HfAl3. The crystal structures belong to the tetragonal structure type ht-TiAl3 (tI8, I4/mmm, a = 3.92395(11), c = 9.0476(4) Å for ZrAl2.52Ge0.48 and a = 3.9021(2), c = 8.9549(8) Å for HfAl2.40Ge0.60). The structure types ZrAl3 and ht-TiAl3 are both members of the family of close-packed structures.

Structural and thermodynamic properties of anionically substituted solid solution ceramics Y(VO4)1-(PO4) with zircon structure

2020 ◽  
Vol 46 (2) ◽  
pp. 2576-2579
Author(s):  
A.P. Kritskaya ◽  
O.N. Kondrat'eva ◽  
G.E. Nikiforova ◽  
M.A. Ryumin ◽  
K.I. Bryukhanova ◽  
...  
Keyword(s):  
Solid Solution ◽  
Thermodynamic Properties ◽  
Zircon Structure

The crystal structures of CeSiO4 and Ca2Ce8(SiO4)6O2

2000 ◽  
Vol 15 (4) ◽  
pp. 234-238 ◽  
Author(s):  
J. M. S. Skakle ◽  
C. L. Dickson ◽  
F. P. Glasser
Keyword(s):  
Hydrothermal Synthesis ◽  
Nuclear Waste ◽  
Structure Type ◽  
Unit Cell ◽  
Apatite Structure ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths ◽  
Zircon Structure

Two new solubility-limiting phases relevant to nuclear waste disposal are reported, namely CeSiO4 and Ca2Ce8(SiO4)O2, produced by hydrothermal synthesis at 180 °C. X-ray diffraction data are presented for both compounds. Rietveld refinement was performed for each of these phases. CeSiO4 was confirmed to be a zircon structure type, with space group I41/amd, unit cell type="bold">abold=6.9564(3), type="bold">cbold=6.1953(4) Å. Bond lengths for SiO4 are in excellent agreement with published values; Ce4+ is coordinated to eight oxygen atoms with four regular and four short bonds. Ca2Ce8(SiO4)O2 was shown to have an apatite structure, with space group P63/m and unit cell type="bold">abold=9.4343(3), type="bold">cbold=6.8885(4) Å. The unit cell and bond lengths were found to be slightly smaller than would be expected from other lanthanide-containing analogs; possible reasons for this are discussed.

scholarly journals Double molybdates of silver and monovalent metals

2021 ◽  
Vol 23 (3) ◽  
pp. 421-431
Author(s):  
Tatiana S. Spiridonova ◽  
Sergey F. Solodovnikov ◽  
Yulia M. Kadyrova ◽  
Zoya A. Solodovnikova ◽  
Alexandra A. Savina ◽  
...  
Keyword(s):  
Solid Solution ◽  
Analysis Data ◽  
Structure Type ◽  
Double Molybdate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Numbers ◽  
Hexagonal Modification ◽  
First Time ◽  
3D Framework

The Ag2MoO4–Cs2MoO4 system was studied by powder X-ray diffraction, the formation of a new double molybdate CsAg3(MoO4)2 was established, its single crystals were obtained, and its structure was determined. CsAg3(MoO4)2 (sp. gr. P3¯, Z = 1, a = 5.9718(5), c = 7.6451(3) Å, R = 0.0149) was found to have the structure type of Ag2BaMn(VO4)2. The structure is based on glaserite-like layers of alternating MoO4 tetrahedra and Ag1O6 octahedra linked by oxygen vertices, which are connected into a whole 3D framework by Ag2O4 tetrahedra. An unusual feature of the Ag2 atom environment is its location almost in the centre of an oxygen face of the Ag2O4 tetrahedron. Caesium atoms are in cuboctahedral coordination (CN = 12).We determined the structures of the double molybdate of rubidium and silver obtained by us previously and a crystal from the solid solution based on the hexagonal modification of Tl2MoO4, which both are isostructural to glaserite K3Na(SO4)2 (sp. gr. P3¯m1). According to X-ray structural analysis data, both crystals have nonstoichiometric compositions Rb2.81Ag1.19(MoO4)2 (a = 6.1541(2), c = 7.9267(5) Å, R = 0.0263) and Tl3.14Ag0.86(MoO4)2 (a = 6.0977(3), c = 7.8600(7) Å, R = 0.0174). In the case of the rubidium compound, the splitting of the Rb/Ag position was revealed for the first time am ong molybdates. Both structures are based on layers of alternating MoO4 tetrahedra and AgO6 or (Ag, Tl)O6 octahedra linked by oxygen vertices. The coordination numbers of rubidium and thallium are 12 and 10

scholarly journals Synthesis, crystal structure and physical properties of the TbCo4.5SixLi0.5-x solid solution

2021 ◽  
Vol 22 (3) ◽  
pp. 577-584
Author(s):  
I. Stetskiv ◽  
V. Kordan ◽  
I. Tarasiuk ◽  
V. Pavlyuk
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Electrode Materials ◽  
Rietveld Method ◽  
Structure Type ◽  
Experimental Conditions ◽  
X Ray ◽  
Cell Parameters ◽  
Arc Melting ◽  
The Stability

Alloys from the region of existence of the solid solution TbCo4.5SixLi0.5-x were synthesized by arc melting. Quantitative and qualitative composition of alloys and powders of electrode materials was determined by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The Tb/Co/Si ratio in the samples was confirmed by X-ray fluorescence spectroscopy. The change in cell parameters within the solid solution existence was established by the results of X-ray powder diffraction (TbCo4.5SixLi0.5-x, x = 0.1–0.4: a = 4.9518(5) – 4.9324(3), c = 3.9727(4) – 3.9746(3) Å). The crystal structure of the solid solution was determined by the Rietveld method (CaCu5 structure type, space group P6/mmm). Cobalt atoms are partially replaced by silicon and lithium only in 2c position. The ability of alloys to reversibly absorb hydrogen was studied by the method of electrochemical hydrogenation. Under experimental conditions the amount of deintercalated hydrogen was about 0.19 H/f.u. The change in cell parameters after hydrogenation (volume increases from 83.74(1) to 85.54(6) Å3) and the stability of the electrode in the electrolyte solution was further confirmed by X-ray phase analysis. Measurements of the electrical resistivity of the samples indicated a decrease of resistivity value with a slight increase in the amount of alkali metal in samples.

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