Structural and electrochemical properties of the binary silicides Eu5Si3 and EuSi

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bohdana Belan ◽  
Marek Daszkiewicz ◽  
Mariya Dzevenko ◽  
Beata Rożdżyńska-Kiełbik ◽  
Volodymyr Pavlyuk ◽  
...  
Keyword(s):  
Coulombic Efficiency ◽  
Specific Capacity ◽  
Structure Type ◽  
Electrochemical Process ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Electrochemical Lithiation ◽  
Charge Process ◽  
Oxford Diffraction

Abstract The crystal structures of Eu5Si3 and EuSi were studied in detail by X-ray single-crystal diffraction. The single crystals were selected from arc-melted and annealed samples. X-ray diffraction was performed at room temperature on an Oxford Diffraction X’calibur Atlas four-circle diffractometer (MoKα radiation). Eu5Si3 adopts the tetragonal Cr5B3-type: space group I4/mcm (# 140), Pearson code tI32, Z = 4, a = 7.9339(6), c = 15.308(2) Å. The compounds with equiatomic composition EuSi crystallize in the structure type TlI: space group Cmcm (# 63), Pearson code oS8, Z = 4, a = 4.6955(6), b = 11.1528(13), c = 3.9845(4) Å. The silicides Eu5Si3 and Li2Si form during electrochemical lithiation (charge process) of EuSi. The electrochemical process 5EuSi + 4Li+ + 4e − ↔ Eu5Si3 + 2Li2Si is reversible, and the discharge specific capacity at 1C rate reached 140 mAhg−1 and the Coulombic efficiency is 93%.

K5[FeO4] und K17[Fe5O16]: Zwei neue Kalium-Oxoferrate(III) / K5[FeO4] and K17[Fe5O16]: Two New Potassium Oxoferrates(III)

2005 ◽  
Vol 60 (12) ◽  
pp. 1224-1230 ◽  
Author(s):  
Gero Frisch ◽  
Caroline Röhr
Keyword(s):  
Linear Chain ◽  
Reaction Times ◽  
Structure Type ◽  
Maximum Temperature ◽  
X Ray Diffraction ◽  
Tetrahedral Geometry ◽  
Space Group ◽  
X Ray ◽  
Subsequent Quenching ◽  
Rich Mixtures

The title compounds were synthesized from potassium rich mixtures of Fe2O3, elemental potassium and the hyperoxide KO2 by applying short reaction times, a maximum temperature of 875 K and subsequent quenching of the samples. The structures of the two new oxoferrates(III) have been determined by single crystal X-ray diffraction. The orthoferrate(III) K5[FeO4] (Na5[GaO4] structure type, space group Pbca, a = 1124,0(2), b = 667,95(9), c = 2034,8(3) pm, Z = 4, R1 = 0,0585) exhibits isolated ortho-anions [FeO4]5− with nearly ideal tetrahedral geometry and Fe-O distance in the narrow range of 189 to 192 pm. The pentaferrate K17[Fe5O16] (space group Cm, a = 671,71(5), b=3560,8(3), c=670,81(5) pm, β =119,687(5)°, Z =2, R1=0,0291) crystallizes with a new structure type. Its building units are isolated novel penta-nuclear anions composed of five corner sharing [FeO4] tetrahedra. These linear chain pieces [Fe5O16] are arranged in a hexagonal rod packing, with a stacking sequence according to |:AB:| along the large monoclinic b axis. The structure is thus related to that of the tetra-ferrate K14[Fe4O13] with a comparable packing of tetra-nuclear ferrate(III) anions.

AlkalineEarthMetal-Hydride-Iodide Compounds: Syntheses andCrystal Structures of Sr2H3I and Ba5H2I3.9(2)O2

2011 ◽  
Vol 66 (1) ◽  
pp. 21-26
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Structural Model ◽  
Structure Type ◽  
Lattice Parameters ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
New Compounds

Single crystals of Sr2H3I andBa5H2I3.9(2)O2 were obtained by reacting Sr or Ba, respectively, with dried and sublimed NH4I in a 4 : 1 molar ratio in silica-jacketed Nb ampoules for 13 h at 1200 K. The crystal structures of the new compounds have been determined by means of single-crystal X-ray diffraction. Sr2H3I crystallizes in a stuffed anti-CdI2 structure isotypic to Ba2H3Cl in the space group P3m1 (no. 164) with the lattice parameters a = 426.0(1) and c = 774.9(2) pm, while Ba5H2I3.9(2)O2 crystallizes in a new structure type in the space group Cmcm (no. 63) with the lattice parameters a = 1721.0(2), b = 1452.5(2) and c = 639.03(9) pm. The structural results for Sr2H3I are corroborated by EUTAX calculations. For the disordered compound Ba5H2I3.9(2)O2, EUTAX calculations on an approximated, ordered structural model were used to find possible insights into the disorder

scholarly journals Disorder in a natural ixiolite: high resolution studies at 293 K and 120 K.

2014 ◽  
Vol 70 (a1) ◽  
pp. C1092-C1092
Author(s):  
Leandro Almeida ◽  
Douglas Miquita ◽  
Bernardo Rodrigues
Keyword(s):  
High Resolution ◽  
General Formula ◽  
Diffraction Data ◽  
High Mobility ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Space Groups ◽  
Independent Observations

Grice, Ferguson and Hawthorne [1] describes the ixiolite of Bernic Lake, Manitoba, Canada. According to these authors, the ixiolite is part of the Ixiolite-Tantalite-Wodgnite system and crystallizes in space group Pbcn, with general formula MO2, in a α-PbO2structure type. The structure of the mineral ixiolite from Volta Grande pegmatite, in Brazil, is herein described from high resolution (0.5 Å) X-ray diffraction data using MoKα radiation. This mineral has formula MO2, with M = Fe, Mn, Nb or Ta. Data were collected at 293 K and at 120 K from a well formed crystal (0.6 x 0.4 x 0.3 mm). 49868 and 32294 reflections were collected at 293 K and at 120 K, respectively. The structure of the ixiolite was well solved in both temperatures: at 293 K the mineral crystalizes in the space group Cmcm, and the structure was refined to R(F2)=0.0476, from 728 independent reflections. At 120 K, the mineral crystalizes in space group Pbcn, and the structure was refined to R(F2)= 0.0537 from 1357 independent observations. It is interesting to notice that the different space groups of the herein described ixiolite at 120 K (Pbcn) and at 293 K (Cmcm) is related to the different occupations of oxygen sites, as expected from the high mobility of oxygen atoms.

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.

Crystal Chemistry of Ternary Rare Earth Transition Metal Carbides: Studies of the Tb-Fe-C System at 800°C

2019 ◽  
Vol 289 ◽  
pp. 12-20
Author(s):  
Volodymyr Levytskyi ◽  
Herwig Michor ◽  
Volodymyr Babizhetskyy ◽  
Bogdan Kotur
Keyword(s):  
Parent Compound ◽  
Structure Type ◽  
Metal Carbides ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Limited Solid Solubility ◽  
Complex Carbides ◽  
Ternary Carbides ◽  
Ferrimagnetic Ordering

The isothermal section of the phase diagram of Tb–Fe–C system at 800 °C was studied in the full concentration range using powder X-ray phase and structure analyses, and energy-dispersive X-ray spectroscopy. Six ternary compounds Tb1.88Fe14C, Tb13Fe10C13, TbFeC2, Tb15Fe8C25, Tb5.64Fe2C9, Tb2FeC4 and a limited solid solubility of carbon in the crystal structure of the binary parent compound Tb2Fe17Cх (0≤ х ≤0.8) have been found to exist at 800 °C. The crystal structures of two new ternary carbides have been determined by means of powder X-ray diffraction: Tb15Fe8C25 with structure type Er15Fe8C25, space group P321, a = 11.9706(3) Å, c = 5.1733(2) Å, RB(I) = 0.07, RP = 0.06, RPw = 0.08, and Tb13Fe10C13 with structure type Gd13Fe10C13, space group P3121, a = 9.1800(9) Å, c = 23.703(5) Å, RB(I) = 0.04, RP = 0.16. Both compounds are representatives of the carbometalate class of complex carbides. Tb15Fe8C25 displays an itinerant ferro-or ferrimagnetic ordering of the Fe 3d-moments below TM ≈ 50 K while Tb 4f-moments remain essentially paramagnetic at least down to about 10 K.

Crystal structure and local order in Co6Al11−x Si6+x

2007 ◽  
Vol 63 (4) ◽  
pp. 551-560 ◽  
Author(s):  
Klaus W. Richter ◽  
Yurii Prots ◽  
Horst Borrmann ◽  
Reiner Ramlau ◽  
Yuri Grin
Keyword(s):  
Model Space ◽  
Structure Type ◽  
Local Order ◽  
X Ray Diffraction ◽  
Metal Compounds ◽  
Space Group ◽  
X Ray ◽  
Arc Melting ◽  
Transmission Electron ◽  
Pearson Symbol

The ternary compound Co6Al_{11-x}Si_{6+x} (∊ phase) was prepared from the elements by arc melting and subsequent heat treatment, and then characterized by single-crystal X-ray diffraction (XRD), electron-probe microanalysis (EPMA), differential thermal analysis (DTA) and transmission electron microscopy (TEM). This new structure type consists of planar layers with the composition [Co6Al10Si4], which are penetrated by perpendicular (Si—Si—Al) chains. While the layers are well described by an orthorhombic model (space group Pnma, Pearson symbol oP46), the chains exhibit doubled periodicity, thus yielding a superstructure. Two alternative ordering models (space group Cmc21, oC184, and space group P21/c, mP92) are presented and discussed based on XRD and TEM results. The (Si—Si—Al) chains are located in pentagonal antiprismatic `channels' which reveal the similarity of the Co6Al_{11-x}Si_{6+x} structure to Al-rich transition-metal compounds such as Co4Al13, Co2Al5, Fe4Al13, V7Al45, V4Al23 and VAl10, which also exhibit this type of pentagonal `channels' in their crystal structures. The phase shows only a very small homogeneity range.

Das erste Oxocuprat/-Arsenat mit Kupfer in gemischter Valenz: Cu(Mg2,56Cu0,44)Cu(AsO4)3 / The First Oxocuprate/Arsenate Containing Mixed Valent Copper:Cu(Mg2,56Cu0,44)Cu(AsO4)3

1994 ◽  
Vol 49 (5) ◽  
pp. 589-592 ◽  
Author(s):  
D. Osterloh ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Single Crystals ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Laser Technique ◽  
Light Blue ◽  
Space Group ◽  
X Ray

Single crystals of Cu(Mg2.56Cu0.44)Cu(AsO4)3 have been prepared by CO2-LASER technique and investigated by X-ray diffraction methods. The light blue crystals show monoclinic sym­metry, space group C62h-C2/c, a = 11.897, b = 12.855, c = 6.688 Å, β = 113.06°, Z = 4. The structure type is characterized by AsO4 tetrahedra, dumb-bell-like coordinated Cu(I), twisted CuO4 square polygons and octahedra statistically occupied by Mg/Cu2+.

Fehlende Glieder bekannter Reihen: Die Oxoferrate(III) Rb8[Fe2O7], Rb6[Fe2O6] und K4[Fe2O5] / Missing Links in Known Series: The Oxoferrates(III) Rb8[Fe2O7], Rb6[Fe2O6], and K4[Fe2O5]

2005 ◽  
Vol 60 (7) ◽  
pp. 732-740 ◽  
Author(s):  
Gero Frisch ◽  
Caroline Röhr
Keyword(s):  
Single Crystal ◽  
Structure Type ◽  
Potassium Ferrate ◽  
X Ray Diffraction ◽  
Marked Contrast ◽  
Ionic Radii ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Alkaline Cations

The title compounds were synthesized at temperatures between 775 and 1175 K from (mostly stoichiometric) mixtures of Fe2O3, elemental rubidium or potassium (A) and their hyperoxides AO2. The structures have been determined by single crystal X-ray diffraction. The alkaline rich ferrate(III) Rb8[Fe2O7] (Cs8[Fe2O7] structure type, space group P21/c, a = 696.7, b = 1722.1, c = 692.0 pm, β = 119.40°, Z = 2, R1 = 0.0496) exhibits diferrate anions [Fe2O7]8- composed of two vertexsharing [FeIIIO4] tetrahedra with a linear Fe-O-Fe bridge and nearly ideal 3m symmetry. This is in marked contrast to the Na homologue, where the diferrate anions are decidedly angular. In the series A3[FeO3], the anions in the compounds of the light alkaline cations are chains 1∞[FeO2O2/2]3−, but similar to the isotypic K6[Fe2O6] and to Cs6[Fe2O6] the new ferrate Rb6[Fe2O6] (K6Fe2O6 structure type, space group C2/m, a=741.8(2), b=1148.7(2), c=680.08(12) pm, β =103.65(2)°, Z = 4, R1 = 0.0370) contains isolated binuclear anions [O2FeO2FeO2]6− composed of two edge sharing [FeO4] tetrahedra. The new potassium ferrate of the series A4[Fe2O5], K4[Fe2O5] (space group P21/c, a = 645.91(14), b = 593.69(13), c = 1003.0(2) pm, β = 103.124(4)°, Z = 4, R1 = 0.0355), constitutes a new structure type, but its structure is still closely related to the Na compound, which crystallizes in the isomorphous subgroup P21/n with a doubled a axis. Both compounds are phylloferrates with layers 2∞[Fe2O5]4− consisting of six-membered rings of [FeO4] tetrahedra. In contrast, Rb4[Fe2O5] contains chains of vertex and edge sharing tetrahedra, so that in both series, A3[FeO3] and A4[Fe2O5], the linkedness of the ferrate tetrahedra increases with the ionic radii of the A counterions.

P(C6H5)4[VOBr4]: Synthese, IR-Spektrum und Kristallstruktur / P(C6H5)4[VOBr4]: Synthesis, IR Spectrum and Crystal Structure

1982 ◽  
Vol 37 (6) ◽  
pp. 699-701 ◽  
Author(s):  
Ulrich Müller ◽  
Abdel-Fatah Shihada ◽  
Kurt Dehnicke
Keyword(s):  
Crystal Structure ◽  
Ir Spectrum ◽  
Structure Type ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Lattice Constants ◽  
Dark Violet ◽  
Stretching Vibration

Abstract PPh4[VOBr4] was prepared by the reaction of PPh4Br with VOBr3 in CH2Br2 solu-tion. The structure of the dark violet crystals was determined with X-ray diffraction. PPh4[VOBr4] crystallizes in the space group P4/n with the lattice constants a = 1275.9 and c = 784.5 pm with two formula units per unit cell. The structure type corresponds to the frequently encountered AsPh4[RuNCl4] type. The VOBr4- ion forms a square pyramid; the V = O bond has a length of 155 pm. In the IR spectrum, the V -O stretching vibration appears at 922 cm-1 .

Kristallstruktur von Na4OBr2 / Crystal Structure of Na4OBr2

1990 ◽  
Vol 45 (2) ◽  
pp. 105-106 ◽  
Author(s):  
Karin Hippler ◽  
Stephan Sitta ◽  
Petra Vogt ◽  
Horst Sabrowsky
Keyword(s):  
Crystal Structure ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Fourier Methods ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Group I

The colourless compound Na4OBr2 has been prepared and its crystal structure determined by X-ray diffraction. Very hygroscopic Na4OBr2 crystallizes in the tetragonal space group I 4/mmm (Z = 2) with the cell parameters a = 452.1(3) and c = 1490.8(1) pm. The structure was solved from 267 symmetry independent reflections by Patterson and Fourier methods (R = 0.028; wR = 0.029). Na4OBr2 crystallizes in the anti-K2NiF4-structure type and is isotypic to Na4OI2 and K4OBr2 which have been described earlier.

Sign in / Sign up

Export Citation Format

Share Document