The isotypic family of the diarsenates MM′As2O7 (M = Sr, Ba; M′ = Cd, Hg)

2016 ◽  
Vol 71 (5) ◽  
pp. 403-409 ◽  
Author(s):  
Matthias Weil
Keyword(s):  
Aqueous Solutions ◽  
Single Crystal ◽  
Metal Oxides ◽  
Structure Type ◽  
Hydrothermal Conditions ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Autogenous Pressure

AbstractThe diarsenates MM′As2O7 (M = Sr, Ba; M′ = Cd, Hg) were prepared under hydrothermal conditions (~200 °C, autogenous pressure), starting from As2O5 and the corresponding metal oxides or precursor compounds thereof in aqueous solutions. Structure analyses on the basis of single crystal X-ray data revealed the four structures to be isotypic. They are the first diarsenates to crystallize in the triclinic BaZnP2O7 structure type (space group P1̅, Z = 2, a ≈ 5.8 Å, b ≈ 7.3 Å, c ≈ 7.6 Å, α ≈ 101°, β ≈ 91°, γ ≈ 98°). All related MM′As2O7 diarsenates reported so far (M = Sr, Ba, Pb; M′ = Mg, Co, Cu, Zn) crystallize in the monoclinic α-Ca2P2O7 structure type (P21/n, Z = 4). Hence, the size of the divalent M′ cation determines which of the two structure types is adopted.

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.

Kristallstruktur von K4O(CN)2 / Crystal Structure of K4O(CN)2

1992 ◽  
Vol 47 (12) ◽  
pp. 1746-1748 ◽  
Author(s):  
Christian Hardt ◽  
Petra Vogt ◽  
Horst Sabrowsky
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Type Space

Colorless K4O(CN)2 has been prepared. The compound crystallizes in the tetragonal anti-K2NiF4 structure type (space group I4/mmm) with a = 515.5(1) and c = 1606.7(3) pm, Z = 2. The structure was determined by single crystal X-ray diffraction, R = 3.35%.

Ba5Al2Ge7 und Ba7Al4Ge9: Zwei neue intermetallische Phasen mit ungewöhnlichen Al-Ge-Anionen / Ba5Al2Ge7 and Ba7Al4Ge9: Two New Intermetallic Phases with Unusual Al-Ge Anions

2007 ◽  
Vol 62 (8) ◽  
pp. 1059-1070 ◽  
Author(s):  
Marco Wendorff ◽  
Caroline Röhr
Keyword(s):  
Ternary System ◽  
Single Crystal ◽  
Structure Type ◽  
Intermetallic Phases ◽  
Crystal Data ◽  
Form Complex ◽  
Space Group ◽  
X Ray ◽  
Al Content ◽  
Binary Section

In the ternary system Ba-Al-Ge new intermetallic compounds which are lying on or close to the binary section BaAl2 -BaGe2 were synthesized from the elements and characterized on the basis of X-ray single crystal data. The Al-content x in the compounds BaAlxGe2−x forming the AlB2 structure type ranges from x = 1.4 [BaAl1.4Ge0.6 space group P6/mmm, a = 443.5(1), c = 512.4(1) pm, Z = 1, R1 = 0.0222] to the stoichiometric ordered compound BaAlGe [space group P6̅m2, a = 434.9(1), c = 513.6 pm, Z = 1, R1 = 0.0252]. In the two new Ge-rich barium intermetallics Ba5Al2Ge7 [space group C2/m, a = 859.8(4), b = 1031.5(4), c = 1847.8(6) pm, β = 103.23(3)°, Z = 4, R1 = 0.0553] and Ba7Al4Ge9 [space group Fmm2, a = 1032.7(5), b = 2559(2), c = 862.1(4) pm, Z = 4, R1 = 0.1197] complex Al/Ge polyanions are present, which consist of (1) Al/Ge-ribbons of condensed planar sixmembered rings comparable to the anions in Ba3Al2Ge2, and (2) [Ge/Al]5 clusters comparable to the anions in the tetrelides Ba3M5. The building units (1) and (2) are connected via Al-Ge bonds to form complex ribbons in the case of Ba5Al2Ge7 and sheets in the case of Ba7Al4Ge9. The electron count in the two compounds supports an interpretation of the structures according to the Zintl concept and the Wades rules. The small formal electron excess, caused by the incomplete transfer of charge from Ba towards the Al/Ge polyanions, decreases with the Ge content of the compound.

Alkaline earth-gold-aluminides: synthesis and structure of SrAu3Al2, SrAu2.83Al2.17, BaAu2.89Al2.11 and BaAu7.09Al5.91

2015 ◽  
Vol 70 (12) ◽  
pp. 903-909 ◽  
Author(s):  
Birgit Gerke ◽  
Rainer Pöttgen
Keyword(s):  
Single Crystal ◽  
Alkaline Earth ◽  
Three Dimensional ◽  
Crystal Chemical ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Annealing Temperatures

AbstractNew alkaline earth-gold-aluminides were synthesized from the elements in sealed tantalum or quartz ampoules in muffle furnaces at maximum annealing temperatures of 1325 K. The structures were refined from single crystal X-ray diffractometer data. SrAu3Al2 crystallizes in an ordered version of the LT-SrZn5 structure: Pnma, a = 1315.9(3), b = 549.0(1), c = 684.5(3) pm, wR2 = 0.0232, 930 F2 values, 35 variables. SrAu2.83Al2.17 (a = 1065.0(2), b = 845.0(2), c = 548.1(1) pm, wR2 = 0.0416, 452 F2 values, 22 variables) and BaAu2.89Al2.11 (a = 1096.1(3), b = 835.7(3), c = 554.0(1) pm, wR2 = 0.0280, 501 F2 values, 22 variables) both adopt the BaZn5 type, space group Cmcm with Au/Al mixing on the 4c site. The gold and aluminum atoms in both types form three-dimensional networks of condensed tetrahedra with the strontium and barium atoms in large cavities. BaAu7.09Al5.91 is a new member of the NaZn13 type: Fm3̅c, a = 1257.6(2) pm, wR2 = 0.0267, 168 F2 values, 12 variables. Both the 96i and 8b sites show Au/Al mixing. The crystal chemical details are discussed.

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

Powder diffraction data of a new compound Al0.35GdGe2

2008 ◽  
Vol 23 (1) ◽  
pp. 60-62 ◽  
Author(s):  
Lingmin Zeng ◽  
Jiejun He ◽  
Pingli Qin ◽  
Xiangzhong Wei
Keyword(s):  
Ternary Compound ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structure Type ◽  
Powder Diffraction Data ◽  
Space Group ◽  
X Ray ◽  
Type Space

A new ternary compound Al0.35GdGe2 has been synthesized and studied by means of X-ray powder diffraction technique. The ternary compound Al0.35GdGe2 crystallizes in the orthorhombicwith the CeNiSi2 structure type (space group Cmcm, a=4.0874(2) Å, b=16.1499(5) Å,c=3.9372(1) Å, Z=4, and Dcalc=8.007 g/cm3).

Compounds Ln5(Ag, Ga)19 – x (Ln = Gd, Tb) – Defective Partially Ordered Representatives of the Rb5Hg19 Structure Type

2005 ◽  
Vol 60 (9) ◽  
pp. 929-932 ◽  
Author(s):  
Roman V. Gumeniuk ◽  
Lev G. Akselrud ◽  
Yurij B. Kuz’ma
Keyword(s):  
Crystal Structures ◽  
Structure Type ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Partially Ordered ◽  
New Compounds

New compounds Ln5(Ag, Ga)19−x (Ln = Gd, Tb) have been found to crystallise with the Rb5Hg19 structure type (space group I4/m). The crystal structures were refined for Gd5Ag1.8Ga15 and Tb5Ag2Ga15.6 from X-ray powder data: a = 9.4635(1), c = 9.8638(2) Å , RI = 0.093 and a = 9.4313(1), c = 9.8491(2) Å , RI = 0.085, respectively. Some positions in the crystal structures of new the compounds are occupied partially.

Crystal data of the low-temperature solid form of 2-methyl-2-nitro-propanol(MNP)

1994 ◽  
Vol 9 (2) ◽  
pp. 84-86 ◽  
Author(s):  
J. Ll. Tamarit ◽  
N. B. Chanh ◽  
P. Négrier ◽  
D. O. López ◽  
M. Barrio ◽  
...  
Keyword(s):  
Low Temperature ◽  
Single Crystal ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Crystal Data ◽  
Powder Diffraction Data ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Solid Form

By means of X-ray single crystal Weissenberg photographs, the crystal of the low-temperature solid form of 2-methyl-2-nitro-propanol, (CH3)2C(NO2)(CH2OH), has been determined and found to be of the monoclinic type, space group P21/c. The cell constants were refined from X-ray powder diffraction data: a=6.195(3) Å, b=19.116(7) Å, c=16.598(7) Å, and β = 90.12(2)° with Z = 12. The indexed pattern at 293 K is given.

scholarly journals Phase equilibria in the Gd–Cr–Ge system at 1070 K

2021 ◽  
Vol 22 (2) ◽  
pp. 248-254
Author(s):  
M. Konyk ◽  
L. Romaka ◽  
Yu. Stadnyk ◽  
V.V. Romaka ◽  
V. Pashkevych
Keyword(s):  
Phase Diagram ◽  
Isothermal Section ◽  
Ternary System ◽  
Electron Microprobe ◽  
Structure Type ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Ternary Compounds ◽  
Pearson Symbol

The isothermal section of the phase diagram of the Gd–Cr–Ge ternary system was constructed at 1070 K over the whole concentration range using X-ray diffractometry, metallography and electron microprobe (EPM) analysis. Three ternary compounds are realized in the Gd–Cr–Ge system at the temperature of annealing: Gd117Cr52Ge112 (Tb117Fe52Ge112 structure type,  space group Fm-3m, Pearson symbol cF1124, a = 2.8971(6) nm), GdCr6Ge6 (SmMn6Sn6 structure type, space group P6/mmm, Pearson symbol hP16, a = 0.51797(2), c = 0.82901(4) nm) and GdCr1-хGe2 (CeNiSi2 structure type, space group Cmcm, Pearson symbol oS16, a = 0.41569(1)-0.41593(8), b = 1.60895(6)-1.60738(3), c = 0.40318(1)-0.40305(8) nm). For the GdCr1-xGe2 compound the homogeneity range was determined (x=0.73 – 0,69).

The platinum-rich scandium silicide Sc2Pt9Si3

2017 ◽  
Vol 72 (8) ◽  
pp. 603-607 ◽  
Author(s):  
Daniel Voßwinkel ◽  
Rainer Pöttgen
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Annealed Sample ◽  
Coordination Polyhedra ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Condensation Pattern

AbstractSingle crystals of Sc2Pt9Si3 have been obtained from an arc-melted and inductively annealed sample of the starting composition Sc:4Pt:2Si. The Sc2Pt9Si3 structure (Tb2Pt9Ge3 type, space group C2/c) was refined from single crystal X-ray diffractometer data: a=1303.4(1), b=749.9(1), c=973.5(1), β=116.44(1)°, wR2=0.0731, 1643 F2 values and 67 variables. The structure contains three basic coordination polyhedra Sc@Pt11, Si1@Pt8 and Si2@Pt8 which show a simple condensation pattern avoiding direct Sc–Si and Si–Si bonding.

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