Neue Chalcogenophosphate: KBaPS4, KBaPSe4 und Ba3PO4PSe4 / New Chalcogenophosphates: KBaPS4, KBaPSe4, and Ba3PO4PSe4

2005 ◽  
Vol 60 (4) ◽  
pp. 431-436 ◽  
Author(s):  
Stefan Jörgens ◽  
Albrecht Mewis
Keyword(s):  
Single Crystals ◽  
Type Structure ◽  
Coordination Polyhedra ◽  
Coordination Numbers ◽  
New Type ◽  
C 30 ◽  
Strong Distortion

Colourless single crystals of KBaPS4 (a = 11.587(2), b = 6.700(1), c = 10.118(2) Å ), and pale orange ones of KBaPSe4 (a = 11.972(2), b = 6.973(1), c = 10.388(2) Å ) were obtained by reactions of Ba3(PS4)2 and Ba3(PSe4)2, respectively, with KCl (790 °C; 30 h). The isotypic compounds crystallize with a slightly modified TlEuPS4 type structure (Pnma, Z = 4); that is, the characteristic units are distorted discrete PX4 tetrahedra (X: S, Se) interconnected by K+ and Ba2+. However, due to the strong distortion of the trigonal X6 prisms along [001] the coordination numbers increase from 8 to 9 for the barium atoms and from 8 to 11 for the potassium atoms. Orange crystals of Ba3PO4PSe4 (a= 6.779(1), b =7.108(1), c =12.727(3)Å ; α = 82.45(3)°, β =78.88(3)°, γ =81.34(3)°) resulted as a by-product of the synthesis of Ba3(PSe4)2. The compound crystallizes in a new type of structure (P1̅; Z = 2) and is the first chalcogenophosphate with discrete PO4 and PSe4 tetrahedra. The coordination polyhedra of the barium atoms are formed by both chalcogen atoms

Der PrPS4-Strukturtyp und eine ”aufgefüllte“ Variante: Die Verbindungen TbPS4 und LiEuPS4 / The PrPS4 Type Structure and a Filled Variant: The Compounds TbPS4 and LiEuPS4

2005 ◽  
Vol 60 (7) ◽  
pp. 705-708 ◽  
Author(s):  
Stefan Jörgens ◽  
Lirija Alili ◽  
Albrecht Mewis
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Type Structure ◽  
C 30

Colourless single crystals of TbPS4 (a = 10.696(2), c = 19.053(4) Å ) were obtained by reaction of the elements (750 °C; 30 h). The compound crystallizes with the PrPS4 type structure (I41/acd; Z = 16). The structure consists of isolated PS4 tetrahedra each surrounded by four Tb3+ cations. Both crystallographically different Tb3+ cations are coordinated by eight sulfur atoms which are part of four PS4 tetrahedra. Orange single crystals of LiEuPS4 (a = 11.498(2), c = 19.882(4) Å ) were prepared by reaction of Eu and P with Li2S4 (700 Å; 20 h). The crystal structure corresponds to the PrPS4 type, in which tubes running along [001] are occupied by Li atoms, which are surrounded by four S atoms in strongly distorted tetrahedra. LiS4 and PS4 tetrahedra are connected via common edges into alternating chains.

Über Oxoplumbate(IV) Die Kristallstruktur von HT-Li2PbO3 [1] The Crystal Structure of HT-Li2PbO3 [1] / On Oxoplumbates(IV) The Crystal Structure of HT-Li2PbO3 [1]

1983 ◽  
Vol 38 (6) ◽  
pp. 661-664 ◽  
Author(s):  
Berthold Brazel ◽  
Rudolf Hoppe
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Structure Determination ◽  
Type Structure ◽  
Ionic Radii ◽  
Space Group ◽  
Coordination Numbers

Abstract Single crystals of HT-Li2PbO3 have been prepared by heating of mixtures of Rb2PbO3 and Li2O [Ag-cylinders, 600 °C, 100 d]. The structure determination [1005 symmetry independent l0(hkl), R = 5.85%, Rw = 5.35%, confirms space group C2/c with a = 548.60(16), b = 949.51(22), c = 1027.35(27) pm, β = 100.11(3)°, drö = 6.78 g · cm-3 , dpyk = 6.80 g · cm-3 , Z - 8. The NaCl-type structure variant is characterized by alter-nating layers of Li+ and Pb4+ /Li+ cations, which are all octahedrally coordinated. Effective Coordination Numbers, ECoN are calculated via Mean Fictive Ionic Radii, MEFIR.

Zur Hochdruckpolymorphie von Bal2 / High Pressure Polymorphism of Bal2

1981 ◽  
Vol 36 (10) ◽  
pp. 1255-1260 ◽  
Author(s):  
H. P. Beck
Keyword(s):  
High Pressure ◽  
Lattice Energy ◽  
Type Structure ◽  
Coordination Polyhedra ◽  
X Ray ◽  
Coordination Numbers ◽  
Bonding Type ◽  
P Type ◽  
Ray Methods

Abstract High pressure investigations of Bal2 yielded a new polymorph, which could be quenched and characterized by X-ray methods. PbCl2-type Bal2 is converted to an anti-Fe2P-type structure with more regular coordination polyhedra and an increase in effective coordination numbers. We discuss changes in bonding type by comparing the Madelung part of lattice energy in the two polymorphs.

Über Oxoplumbate(IV). Die Kristallstruktur von TT-Li2PbO3 [1] .On Oxoplumbates(IV) The Crystal Structure of LT-Li2PbO3 [1]

1982 ◽  
Vol 37 (11) ◽  
pp. 1369-1374 ◽  
Author(s):  
Berthold Brazel ◽  
Rudolf Hoppe
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Structure Determination ◽  
Lattice Energy ◽  
Type Structure ◽  
Ionic Radii ◽  
Glass Ampoule ◽  
Space Group ◽  
Coordination Numbers ◽  
First Time

For the first time single crystals of LT-Li2PbO3 have been prepared by decomposition of K2Li6[Pb2O8] [Incompletely closed Ag cylinders, sealed in Supremax-glass ampoule, vacuum, 690 °C, 100 d]. The structure determination [533Io(hkl); four-circle-diffractometer PW 1100, ω - scan, Mo - Kα, R = 4,86%, Rw = 4,93% confirms space group C2/c with a = 544.52(7), b = 926.12(7), c = 547,56(8) pm, β = 111.216(13)°, Z = 4, drö = 6.94 g · cm-3, dpyk = 6.89 g · cm-3. The NaCl-type structure variant is characterized by alternating layers of Li(2)+ and Li(l)+/Pb4+ cations. All atoms have octahedral coordination. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, are calculated.

The Microstructure of Shock-Synthesized Diamond

1967 ◽  
Vol 25 ◽  
pp. 324-325
Author(s):  
Lucien F. Trueb
Keyword(s):  
Single Crystals ◽  
Preferred Orientation ◽  
High Magnification ◽  
Texture Pattern ◽  
Shock Process ◽  
New Type ◽  
Diffraction Diagram

A new type of synthetic industrial diamond formed by an explosive shock process has been recently developed by the Du Pont Company. This material consists of a mixture of two basically different forms, as shown in Figure 1: relatively flat and compact aggregates of acicular crystallites, and single crystals in the form of irregular polyhedra with straight edges.Figure 2 is a high magnification micrograph typical for the fibrous aggregates; it shows that they are composed of bundles of crystallites 0.05-0.3 μ long and 0.02 μ. wide. The selected area diffraction diagram (insert in Figure 2) consists of a weak polycrystalline ring pattern and a strong texture pattern with arc reflections. The latter results from crystals having preferred orientation, which shows that in a given particle most fibrils have a similar orientation.

The Gold Sulfates MAu(S04)2 (M = Na, K, Rb)

2001 ◽  
Vol 56 (12) ◽  
pp. 1340-1343 ◽  
Author(s):  
Mathias S. Wickleder ◽  
Oliver Büchner
Keyword(s):  
Sulfuric Acid ◽  
Single Crystals ◽  
Crystal Structures ◽  
Structural Features ◽  
Monovalent Cations ◽  
Coordination Numbers ◽  
Square Planar ◽  
Oxygen Atoms

AbstractThe evaporation of a solution of Au(OH)3 and Na2So4 in conc. sulfuric acid led to yellow single crystals of NaAu(SO4)2 (monoclinic, P21/n, Z = 2, a = 469.1, b = 845.9, c = 831.2 pm, β = 95.7°). Analogous procedures with K2SO4 or Rb2SO4 instead of Na2SO4 yielded single crystals of KAu(SO4)2 (monoclinic, C2/c, Z = 4, a = 1109.8, b = 724.2, c = 941.1 pm, β = 118.4°) and RbAu(S04)2, respectively, (triclinic, P1̄, Z = 1, a = 423.6, b = 497.5, c = 889.0 pm, a = 76.4°, β = 88.4°, γ = 73.5°). Although the crystal structures of the three sulfates are not isotypic they show similar structural features: The gold atoms are coordinated by four oxygen atoms in a square planar manner. These oxygen atoms belong to four SO42- ions which link the [AUO4] units to infinite chains according to 1∞[Au(SO4)4/ 2]- . These chains are connected via the monovalent cations which show coordination numbers of 6 (Na+), 10 (K+) and 12 (Rb+), respectively.

A-Pr2S3, D-Ho2S3 und E-Yb2S3:Synthese und Einkristallstrukturuntersuchungen / A-Pr2S3, D-Ho2S3 and E-Yb2S3:Synthesis and Single Crystal Structure Investigations

1996 ◽  
Vol 51 (5) ◽  
pp. 733-738 ◽  
Author(s):  
Thomas Schleid ◽  
Falk Lissner
Keyword(s):  
Crystal Structure ◽  
Crystal Growth ◽  
Single Crystals ◽  
Alkali Halides ◽  
Structural Investigations ◽  
Coordination Numbers ◽  
Trivalent Lanthanides ◽  
Trivalent Cations ◽  
Structure Investigations ◽  
Type Orthorhombic

The oxidation of reduced chlorides (MCl2) or chloride-hydrides (MClHx) of the lanthanides with sulfur (700-850 °C, 7 d, sealed tantalum capsules or evacuated silica vessels) usually results in the formation of the sesquisulfides M2S3 as the main products. In the presence of appropriate fluxes (e.g., alkali halides), the products often are obtained as single crystals, and the flux decides which modification is favoured. Ternary halides of the trivalent lanthanides with the corresponding alkali metal can mostly be found as the second components. Crystal growth and structural investigations of thus produced single crystals of Pr2S3 (from PrClH0.67 + S + NaCl, 5:5:1, A type: orthorhombic, Pnma (No. 62), Z = 4, a = 748.22(5), b = 405.51(3), c = 1560.74(9) pm, R = 0.024, Rw = 0.020), Ho2S3, (from U - Ho2S3, + KI, 1:1, D type: monoclinic, P21/m (No. 12), Z = 6, a = 1746.15(9), b = 400.23(3), c = 1012.43(6) pm, β = 98.529(4)°, R = 0.041, Rw = 0.035), and Yb2S3 (from T-Yb2S3 + KI, 1:1, E type: trigonal, R3̄c (No. 167), Z = 6, a = 674.97(2), c = 1820.11(9) pm, R = 0.019, Rw = 0.018) are reported here. In accordance with the lanthanide contraction, the trivalent cations (M3+) exhibit sulfur coordination numbers of 7 and 8 in A -Pr2S3, 6 and 7 in D -Ho2S3, and 6 in E -Yb2S3 (corundum-type structure).

On the dimorphism of Pr6Mo10O39

2017 ◽  
Vol 72 (11) ◽  
pp. 765-774
Author(s):  
Daniel Rudolph ◽  
Sonja Laufer ◽  
Ingo Hartenbach
Keyword(s):  
Crystal Structure ◽  
Thermal Decomposition ◽  
Single Crystals ◽  
Main Product ◽  
Molar Ratio ◽  
Coordination Environment ◽  
Space Group ◽  
Coordination Numbers ◽  
Dense Modification

AbstractAttempts to synthesize Pr4Mo7O27 using Pr, Pr6O11 and MoO3 in a molar ratio of 8:6:77 led to a main product of scheelite-type Pr0.667[MoO4] and few single crystals of the triclinic A-type Pr6Mo10O39. The latter crystallizes in space group P1̅ (a=945.25(1), b=1058.49(2), c=1815.16(3) pm; α=104.149(1), β=95.220(1), γ=102.617(1)°, Z=2). Its crystal structure comprises six crystallographically independent Pr3+ cations, eight tetrahedral [MoO4]2− units, and one [Mo2O7]2− entity. The cations display coordination numbers of seven (1×) and eight (5×), while the [MoO4]2− tetrahedra are surrounded by five Pr3+ cations each. The [Mo2O7]2− anions exhibit a coordination environment of seven Pr3+ cations. The attempt to synthesize PrF[MoO4] using PrOF (from in situ thermal decomposition of PrF[CO3]) as reagent did not lead to the desired product but to monoclinic B-type Pr6Mo10O39. This slightly less dense modification compared to its triclinic analogue crystallizes in space group C2/c (a=1247.93(3), b=1989.68(6), c=1392.52 (4) pm, β=100.505(2)°, Z=4) with three crystallographically independent Pr3+ cations, four [MoO4]2− tetrahedra, and again one [Mo2O7]2− unit in the crystal structure. Thus, both Pr6Mo10O39 modifications are better described with the structured formula Pr6[MoO4]8[Mo2O7]. The coordination numbers around the Pr3+ cations are seven (1×) and eight (2×) while all four [MoO4]2− anions are again surrounded by five Pr3+ cations each. Six of the latter represent the coordination environment around the [Mo2O7]2− entities. Besides the thorough comparison of the crystal structures single crystal Raman spectra were recorded for both Pr6Mo10O39 phases.

Dimorphic ThNi2P2 with BaCu2S2 and CaBe2Ge2 Type Structure

1994 ◽  
Vol 49 (8) ◽  
pp. 1074-1080 ◽  
Author(s):  
Jörg H. Albering ◽  
Wolfgang Jeitschko
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Crystal Structures ◽  
Type Structure ◽  
Variable Parameters ◽  
Higher Symmetry ◽  
X Ray ◽  
Coordination Numbers ◽  
Structure Factors ◽  
High Temperature Form

Two modifications of ThNi2P2 were prepared in a tin flux at 850 °C (α-ThNi2P2) and 1000 °C (β-ThNi2P2). The crystal structures of both modifications were refined from single­crystal X-ray data. α-ThNi2P2 (BaCu2S2 type structure): Pnma. a = 819.69(5), b = 394.28(3), c = 981.54(7) pm. R = 0.028 for 32 variables and 654 structure factors: β-ThNi2P2 (CaBe2Ge2 type structure): P4/nmm, a = 408.5(1), c = 908.0(3) pm, R = 0.033 for 15 variable parameters and 261 F values. Although the two structures are closely related, they can be transformed into each other only by a reconstructive phase transformation. The differences and similari­ties of the two structures are discussed. The high temperature form has higher symmetry, a smaller number of variable positional parameters, and a tendency for higher coordination numbers.

A New Class of Oxide Superconductor (Nd, Ce, Sr)2CuO4

1989 ◽  
Vol 156 ◽  
Author(s):  
E. Takayama-Muromachi
Keyword(s):  
Crystal Structure ◽  
Crystal Chemistry ◽  
Superconducting Phase ◽  
Type Structure ◽  
Oxide Superconductor ◽  
New Class ◽  
System 2 ◽  
New Type ◽  
System 1 ◽  
Tetragonal Cell

ABSTRACTSince the discovery of the high-Tc superconductor in the La-Ba-Cu-O system [1], a great deal of experimental and theoretical effort have been made to clarify the nature of the Cu-based oxides. In order to elucidate mechanism of the high-Tc superconductivity, discovery of a new type of superconductor is no doubt of great importance. Recently, Akimitsu et al. found a new oxide superconductor in the Nd-Ce-Sr-Cu-O system [2]. Soon after their discovery, the superconducting phase was isolated and identified [3]. It has a tetragonal cell with space group P4/nmm and has a structure closely related to but different from the K2NiF4− or T'-Nd2CuO4− -type structure. Although, Tc of the Nd-Ce-Sr-Cu oxide is not so high (ca. 20 K) compared with the 1–2–3 or Bi(Tl)-based superconductors, it has aroused interest widely due to a very simple crystal structure. In this article, I will discuss superconductivity and crystal chemistry of the Nd-Ce-Sr-Cu oxide. Also, various compounds isostructural to it will be presented.

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