Die Lanthanoid(III)-Chlorid-Oxoselenate(IV) MCl[SeO3] (M = Sm–Lu) imHoCl[TeO3]- oder B-Typ / The Lanthanoid(III) Chloride Oxoselenates(IV) MCl[SeO3] (M = Sm–Lu) with HoCl[TeO3]- or B-Type Structure

2008 ◽  
Vol 63 (3) ◽  
pp. 229-236 ◽  
Author(s):  
Christian Lipp ◽  
Thomas Schleid
Keyword(s):  
Three Dimensional ◽  
Eutectic Mixture ◽  
Structure Type ◽  
Selenium Dioxide ◽  
Type Structure ◽  
Dimensional Structure ◽  
Normal Range ◽  
Orthorhombic Space Group ◽  
Coordination Numbers ◽  
Lattice Constants

The B-type lanthanoid(III) chloride oxoselenates(IV) MCl[SeO3] (M = Sm- Lu) crystallize in the orthorhombic space group Pnma (no. 62) with Z = 4 in the structure type of HoCl[TeO3]. Their lattice constants are decreasing following the lanthanoid contraction from a = 730.01(7), b = 707.90(7), c = 895.64(9) pm for SmCl[SeO3] to a = 714.63(7), b = 681.76(7), c = 864.05(9) pm for LuCl[SeO3]. In contrast to NdCl[SeO3], the only representative of the A-type structure, where the coordination numbers of the Nd3+ cations are 7+2 and 8, the B-type structure is dominated by pentagonal bipyramids [MO5Cl2]9− (CN(M3+) = 7), which are connected via trans-oriented O・ ・ ・O edges to 1∞{[MOe4/2Ot1/1Clt2/1]5−} chains (e = edge-sharing, t = terminal) running parallel to the [010] direction. Their inclination relative to each other allows for an alternating interconnection of these chains via Cl− and ψ1-tetrahedral [SeO3]2− anions to form a three-dimensional structure. The distances within the [SeO3]2− groups are in the normal range (d(Se−O) = 165 - 172 pm), while those of the O2− and Cl− anions to the central M3+ cation diminish in dependence of the increasing atomic number (d(M−O) = 226 - 244 pm / 216 - 232 pm, d(M−Cl) = 277 - 278 pm / 266 - 270 pm, M = Sm/Lu). For the synthesis of the chloride oxoselenates(IV) MCl[SeO3] the respective lanthanoid sesquioxide (M2O3) and selenium dioxide (SeO2) were reacted with either an eutectic mixture of RbCl and LiCl or with the corresponding lanthanoid trichloride (MCl3) in evacuated silica ampoules for either five weeks at 500 °C or one week at 850 °C.

Strukturvarianten des MgCu2-Typs: Die Verbindungen Mg2Ni3P und Mg2Ni3As / Variants of the MgCu2 Type: The Compounds Mg2Ni3P and Mg2Ni3As

1992 ◽  
Vol 47 (10) ◽  
pp. 1351-1354 ◽  
Author(s):  
Viktor Keimes ◽  
Albrecht Mewis
Keyword(s):  
Single Crystal ◽  
Homogeneity Range ◽  
Hexagonal Lattice ◽  
Structure Type ◽  
Type Structure ◽  
X Ray ◽  
Lattice Constants ◽  
Metal Atoms ◽  
Rhombohedral Symmetry

The compounds Mg2Ni3P and Mg2Ni3As were prepared by heating the elements. Their structures have been determined from single-crystal X-ray data. The structure of the phosphide is a rhombohedral ternary variant of the cubic Laves structure type MgCu2 (R 3̄ m; hexagonal lattice constants: a = 4.971(0) Å, c = 10.961(2) Å). The ordered substitution of one quarter of the metal atoms by phosphorus and the resulting shorter distances are responsible for the rhombohedral symmetry.The arsenide crystallizes in the MgCu2 type structure (Fd 3 m; a = 6.891(1)A, composition Mg2Ni3As) with a statistic distribution of the Ni and As atoms; the relevant homogeneity range extends from Mg2Ni2.9As1.1 to Mg2Ni3.5As0.5.

scholarly journals Hydrothermal Synthesis and Structural Investigation of a Crystalline Uranyl Borosilicate

Inorganics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 25
Author(s):  
Kristen A. Pace ◽  
Vladislav V. Klepov ◽  
Mark D. Smith ◽  
Travis Williams ◽  
Gregory Morrison ◽  
...  
Keyword(s):  
Synthesis Method ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Exploratory Research ◽  
The Novel ◽  
Orthorhombic Space Group ◽  
Crystalline Materials ◽  
Waste Remediation ◽  
And Storage ◽  
X Ray Absorption

The relevance of multidimensional and porous crystalline materials to nuclear waste remediation and storage applications has motivated exploratory research focused on materials discovery of compounds, such as actinide mixed-oxoanion phases, which exhibit rich structural chemistry. The novel phase K1.8Na1.2[(UO2)BSi4O12] has been synthesized using hydrothermal methods, representing the first example of a uranyl borosilicate. The three-dimensional structure crystallizes in the orthorhombic space group Cmce with lattice parameters a = 15.5471(19) Å, b = 14.3403(17) Å, c = 11.7315(15) Å, and V = 2615.5(6) Å3, and is composed of UO6 octahedra linked by [BSi4O12]5− chains to form a [(UO2)BSi4O12]3− framework. The synthesis method, structure, results of Raman, IR, and X-ray absorption spectroscopy, and thermal stability are discussed.

Gemischte Alkalimetall-Oxidosulfidomolybdate A2[MoOxS4– x] (x = 1, 2, 3; A = K, Rb, Cs, NH4). Synthesen, Kristallstrukturen und Eigenschaften / Mixed Alkali Oxidosulfidomolybdates A2[MoOxS4−x] (x = 1, 2, 3; A = K, Rb, Cs, NH4).Synthesis, Crystal Structure and Properties

2012 ◽  
Vol 67 (2) ◽  
pp. 127-22
Author(s):  
Anna J. Lehner ◽  
Korina Kraut ◽  
Caroline Röhr
Keyword(s):  
Bathochromic Shift ◽  
Structure Type ◽  
Structure Theory ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Coordination Numbers ◽  
Preparation Conditions ◽  
Vis Spectroscopy ◽  
Type Orthorhombic

Mixed sulfido/oxidomolybdate anions [MoOxS4−x]2− (x = 1, 2, 3) have been prepared by passing H2S gas through a solution of oxidomolybdates. The alkali salts of K+, Rb+, Cs+, and NH+4 precipitate as crystalline salts from these solutions depending on the pH, the polarity of the solvent, the educt concentrations and the temperature. Their structures have been determined by means of X-ray single-crystal diffraction data. All trisulfidomolybdates A2[MoOS3] (A = NH4/K/Rb/Cs) are isotypic with the tetrasulfido salts, exhibiting the β -K2[SO4] type (orthorhombic, space group Pnma, Z = 4; for A = Rb: a = 940.62(4), b = 713.32(4), c = 1164.56(5) pm, R1 = 0.0281). In contrast, the disulfidomolybdates exhibit a rich crystal chemistry, forming three different structure types depending on the preparation conditions and the size of the A cation: All four cations form salts crystallizing with the (NH4)2[WO2S2] structure type (monoclinic, space group C2/c, Z = 4, for A = Rb: a = 1144.32(11), b = 732.60(4), c = 978.99(10) pm, β = 120.324(7)°, R1 = 0.0274). For the three alkali metal cations a second polymorph with a new structure type (monoclinic, space group P21/c, Z = 4) is observed in addition (for A = Rb: a = 674.83(2), b = 852.98(3), c = 1383.10(9) pm, β = 115.19(1)°, R1 = 0.0216). The cesium salt also crystallizes with a third modification of another new structure type (orthorhombic, space group Pbcn, Z = 4, a = 915.30(6), b = 777.27(7), c = 1120.02(7) pm, R1 = 0.0350). Only for K, an anhydrous monosulfidomolybdate could be obtained (K2[MoO4] structure type, monoclinic, space group C2/m, Z = 4, a = 1288.7(3), b = 615.7(2), c = 762.2(1) pm, β = 109.59(1)°, R1 = 0.0736). The intramolecular chemical bonding in the molybdate anions is discussed and compared with the respective vanadates. Hereby aspects like bond lengths, bond strengths and force constants derived from Raman spectroscopy, are taken into account. Especially for the polymorphic disulfido salts, in-depth analyses of the local coordination numbers and the packing of the ions are presented. The gradual bathochromic shift of the crystal color with increasing S content and increasing size of the counter cations A and molar volumes (for the polymorphic forms), respectively, is in accordance with the increase of the experimental (UV/Vis spectroscopy) and calculated (FP-LAPW band structure theory) band gaps.

scholarly journals Acmonidesite, a new ammonium sulfate chloride from La Fossa crater, Vulcano, Aeolian Islands, Italy

2018 ◽  
Vol 83 (1) ◽  
pp. 137-142 ◽  
Author(s):  
Francesco Demartin ◽  
Carlo Castellano ◽  
Italo Campostrini
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Chlorine Atoms ◽  
Calculated Density ◽  
Sulfate Ions ◽  
Aeolian Islands ◽  
Fossa Crater

AbstractThe new mineral acmonidesite, (NH4,K,Pb2+,Na)9Fe42+(SO4)5Cl8, was found in an active fumarole (fumarole FA, temperature ~250°C) at La Fossa crater, Vulcano, Aeolian Islands, Sicily, Italy. It occurs on a pyroclastic breccia as brown prismatic crystals up to 0.10 mm long, in association with salammoniac, alunite and adranosite. The mineral is orthorhombic, space group C2221 (no. 20) with a = 9.841(1), b = 19.448(3) c = 17.847(3) Å, V = 3415.7(9) Å3 and Z = 4. The six strongest reflections in the powder X-ray diffraction pattern are: [dobs in Å(I)(hkl)] 8.766(100)(110), 1.805(88)(390), 5.178(45)(131), 4.250(42)(221), 2.926(42)(330) and 2.684(32)(261). The empirical formula (based on 28 anions per formula unit [pfu]) is (NH4)5.77K1.42Pb0.62Na1.24Fe3.96Mn0.08S5.04O20.16Cl7.97Br0.08. The idealised formula is (NH4,K,Pb2+,Na)9Fe42+(SO4)5Cl8. The calculated density is 2.551 g cm–3. Using single-crystal diffraction data, the structure was refined to a final R(F) = 0.0363 for 4614 independent observed reflections [I > 2σ(I)]. The structure contains two independent, distorted octahedral iron sites, Fe1 and Fe2, with the iron atoms in the 2+ oxidation state, as confirmed by the interatomic distances and bond-valence calculations (2.06 and 1.94 vu, respectively). Fe1 is surrounded by two chlorine atoms and four oxygens of the sulfate ions, with the following average distances (Å): Fe1–O 2.125 and Fe1–Cl 2.472; and Fe2 is surrounded by three chlorine atoms and three oxygens of the sulfate ions, with the following average distances (Å): Fe2–O 2.110 and Fe2–Cl 2.531. Three independent sulfate anions are also present and are connected with the iron polyhedra to form a three-dimensional structure containing voids occupied by four independent ammonium ions (two of them partially replaced by K+), one Na+/Pb2+ site and one Cl– ion.

Pressure-Induced Phase Transition of the Alkali Metal Amalgam KHg2

1993 ◽  
Vol 48 (1) ◽  
pp. 11-14 ◽  
Author(s):  
Heinz-Jürgen Beister ◽  
Karl Syassen ◽  
Hans-Jörg Deiseroth ◽  
Dirk Toelstede
Keyword(s):  
Phase Transition ◽  
Major Change ◽  
Normal Pressure ◽  
Structure Type ◽  
Type Structure ◽  
Lattice Constants ◽  
First Order ◽  
Β Phase ◽  
First Order Phase Transition ◽  
First Order Phase

Potassium amalgam , KHg2, is a shiny black-purple air-sensitive alloy crystallizing, like RbHg2 and CsHg2, in the CeCu2 structure type, which is an open variant of the AlB2 type. We have investigated the phase stability of KHg2 under pressure by powder X -ray diffraction. At 25 kbar KHg2 undergoes a reversible first order phase transition into the AlB2-type structure. Lattice constants and interatomic distances of the high pressure β-phase phase near the phase transition are close to the values for normal pressure NaHg2 which also crystallizes in the AlB2-type structure. The extremely short K - K distances in the β-phase (dK-K = 3.23 Å) indicate that a major change in charge transfer between K atoms and Hg sublattice is associated with the first-order structural transition, driving the potassium atoms towards a positively charged K+ state.

scholarly journals Synthesis, crystal structure and charge-distribution validation of a new alluaudite-type phosphate, Na2.22Mn0.87In1.68(PO4)3

2020 ◽  
Vol 76 (8) ◽  
pp. 1369-1372
Author(s):  
Abdessalem Badri ◽  
Inmaculada Alvarez-Serrano ◽  
María Luisa López ◽  
Mongi Ben Amara
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Three Dimensional ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Flux Method ◽  
X Ray ◽  
Coordination Numbers ◽  
Dimensional Network ◽  
Anionic Framework

Na2.22Mn0.87In1.68(PO4)3, sodium manganese indium tris(phosphate) (2.22/0.87/1.68), was obtained in the form of single crystals by a flux method and was structurally characterized by single-crystal X-ray diffraction. The compound belongs to the alluaudite structure type (space group C2/c) with general formula X(2)X(1)M(1)M(2)2(PO4)3. The X(2) and X(1) sites are partially occupied by sodium [occupancy 0.7676 (17) and 1/2] while the M(1) and M(2) sites are fully occupied within a mixed distribution of sodium/manganese(II) and manganese(II)/indium, respectively. The three-dimensional anionic framework is built up on the basis of M(2)2O10 dimers that share opposite edges with M(1)O6 octahedra, thus forming infinite chains extending parallel to [10\overline{1}]. The linkage between these chains is ensured by PO4 tetrahedra through common vertices. The three-dimensional network thus constructed delimits two types of hexagonal channels, resulting from the catenation of M(2)2O10 dimers, M(1)O6 octahedra and PO4 tetrahedra through edge- and corner-sharing. The channels are occupied by Na+ cations with coordination numbers of seven and eight.

scholarly journals The Role of Different Alkali Metals in the A15Tl27 Type Structure and the Synthesis and X-ray Structure Analysis of a New Substitutional Variant Cs14.53Tl28.4

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7512
Author(s):  
Vanessa F. Schwinghammer ◽  
Susanne M. Tiefenthaler ◽  
Stefanie Gärtner
Keyword(s):  
Alkali Metal ◽  
Alkali Metals ◽  
Three Dimensional ◽  
Structure Type ◽  
Binary Compound ◽  
Type Structure ◽  
Two Dimensional ◽  
Unique Type ◽  
X Ray ◽  
Quaternary Compounds

Alkali metal thallides have been known since the report of E. Zintl on NaTl in 1932. Subsequently, binary and ternary thallides of alkali metals have been characterized. At an alkali metal proportion of approximately 33% (A:Tl~1:2, A = alkali metal), three different unique type structures are reported: K49Tl108, Rb17Tl41 and A15Tl27 (A = Rb, Cs). Whereas Rb17Tl41 and K49Tl108 feature a three-dimensional sublattice of Tl atoms, the A15Tl27 structure type includes isolated Tl11 clusters as well as two-dimensional Tl-layers. This unique arrangement is only known so far when the heavier alkali metals Rb and Cs are included. In our contribution, we present single-crystal X-ray structure analyses of new ternary and quaternary compounds of the A15Tl27 type structure, which include different amounts of potassium. The crystal structures allow for the discussion of the favored alkali metal for each of the four Wyckoff positions and clearly demonstrate alkali metal dependent site preferences. Thereby, the compound Cs2.27K12.73Tl27 unambiguously proves the possibility of a potassium-rich A15Tl27 phase, even though a small amount of cesium appears to be needed for the stabilization of the latter structure type. Furthermore, we also present two compounds that show an embedding of Tl instead of alkali metal into the two-dimensional substructure, being equivalent to the formal oxidation of the latter. Cs14.53Tl28.4 represents the binary compound with the so far largest proportion of incorporated Tl in the structure type A15Tl27.

Rh2Sb with (anti-)PbCl2-Type Structure

1990 ◽  
Vol 45 (7) ◽  
pp. 947-951 ◽  
Author(s):  
Wolfgang Jeitschko ◽  
Rainer O. Altmeyer
Keyword(s):  
Single Crystal ◽  
Crystal Chemistry ◽  
Homogeneity Range ◽  
Type Structure ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Lattice Constants ◽  
Rich Side

Crystals of Rh2Sb were prepared by sintering the elemental components in a NaCl/KCl flux. They crystallize in the orthorhombic space group Pnma with the lattice constants α = 572.1(1)-573.6(1) pm, b = 417.1(1)-418.1(1) pm, c = 792.8(2)-794.9(1) pm, V = 0.1892-0.1906 nm3 for the antimony- and rhodium-rich side, respectively, of the homogeneity range at 800 °C. The structure belongs to the Co2Si-branch of the (anti-)PbCl2-type. It was refined from single-crystal diffractometer data to a residual R = 0.059. The crystal chemistry of the various PbCl2-type compounds is briefly reviewed.

Interpenetrierende Clusterstränge in der Kristallstruktur von K0,77Nb6Cl15 / Interpenetrating Cluster Chains in the Structure of K0.77Nb6Cl15

2001 ◽  
Vol 56 (11) ◽  
pp. 1238-1240 ◽  
Author(s):  
Andreas Nägele ◽  
Cynthia Day ◽  
Abdessadek Lachgar ◽  
H.-Jürgen Meyer
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Solid State Reaction ◽  
Three Dimensional ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Lattice Constants ◽  
A Value ◽  
Dimensional Network ◽  
Ray Methods

The solid state reaction of KCl, NbCl5 and Nb powder at 760 °C yielded black crystals of KNb6Cl15. The structure of the compound has been determined using single-crystal X-ray methods. KNb6Cl15 crystallizes in the orthorhombic space group Pmma (no. 51) with lattice constants a = 1780.1(2), b = 1341.4(1), and c = 925.5(1) pm, Z = 4, and R1 = 0.039 for all 2727 observed reflections.[(Nb6Cl12i)Cl6/2a-a]- anions in the structure are linked via two Cla-a bridges to form one set of linear and one set of kinked chains along the crystallographic c and a directions. Four remaining Cla-a bridges interconnect both sets of chains to a three-dimensional network. The potassium occupancy on a 4k site was refined to a value of 0.384(3) consistent with the formula K0.77Nb6Cl15-. Ternäre Niobchloride des Formeltyps ANb6Cl15 wurden bereits verschiedentlich beschrieben. Verbindungen mit A = Li [1] und Na [2] kristallisieren kubisch (Ia3̅d) mit identischen Schweratomstrukturen. Die Alkalimetall-Ionen Li (KZ = 4) und Na (KZ = 6 ) besetzen in den Strukturen ANb6Cl15 aber unterschiedliche Splitlagen und sind dynamisch fehlgeordnet. Die Vertreter mit A = In und TI [3] kristallisieren orthorhombisch (Pmma). Ihre Kationen befinden sich in zweifach überdachten, würfelförmigen Cl-Umgebungen (KZ = 10). Die Kenntnis des Formeltyps ANb6Cl15 mit schweren Alkalimetallen ist noch unvollständig. Einkristallstrukturuntersuchungen für A = Rb, Cs ergaben Kationenfehlordnungen [4, 5]. Für die Verbindung KNb6Cl15 wurde eine Einkristallstrukturbestimmung durchgeführt (Tab. 1). Die Verbindung kristallisiert orthorhombisch in der Raumgruppe Pmma (Nr. 51) mit den Gitterkonstanten a = 1780,1(2), b = 1341,4(1) und c = 925,5(1) pm mit Z = 4 und ist isotyp zu den Inund TI-Verbindungen. Die Besetzung der K-Position (4k-Lage, mx-Punktsymmetrie) wurde zu 0,384(3) verfeinert, was der Zusammensetzung K0.77Nb6Cl15 entspricht (Tab. 2)#. Die Nb-Nb-Abstände in KNb6Cl15 liegen zwischen 291,47(6) und 296,45(7) pm, die Bindungslängen Nb-ClI betragen 243,3(1) - 247,18(9) und die Nb-Cla-Abstände 258,7(2) - 271,40(9) pm.

Three of a kind? The non-isotypic triple CsCe[P2Se6], CsSm[P2Se6] and CsEr[P2Se6]

2020 ◽  
Vol 75 (11) ◽  
pp. 959-967
Author(s):  
Beate M. Schulz ◽  
Pia L. Lange ◽  
Thomas Schleid
Keyword(s):  
Three Dimensional ◽  
Structure Type ◽  
Fused Silica ◽  
Double Layers ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Coordination Polyhedra ◽  
Space Group ◽  
New Compounds ◽  
Dimensional Crystal

AbstractThree new compounds of the CsLn[P2Se6] family with Ln = Ce, Sm and Er have been prepared and structurally characterized. Plate-shaped, amber-colored single crystals of these cesium lanthanoid(III) hexaselenodiphosphates(IV) were obtained by heating stoichiometric amounts of Ln, P and Se with CsCl as a reactive flux in fused silica ampoules at 800 °C for four days. CsCe[P2Se6] crystallizes monoclinically in space group P21/c with a = 1297.86(9), b = 776.24(5), c = 1198.43(8) pm, β = 106.589(3)° and Z = 4. The structure is isotypic with that of KLa[P2Se6], the Cs+ cations being ten-fold coordinated by selenium atoms to form double layers of condensed [CsSe10]19− polyhedra. Ce3+ resides in a nine-fold coordination and the [CeSe9]15− polyhedra also form double layers parallel to (100). CsSm[P2Se6] crystallizes in the orthorhombic space group P212121 with a = 688.67(5), b = 754.48(5), c = 2215.21(15) pm and Z = 4. Its structure is isotypic with that of KY[P2Se6] and the Cs+ cations reside in an eleven-fold coordination of selenium atoms constituting monolayers of condensed [CsSe11]21− polyhedra within the (001) plane. Sm3+ exhibits an eight-fold coordination sphere of selenium atoms and the [SmSe8]13− polyhedra are also linked to build up parallel monolayers. CsEr[P2Se6] crystallizes in the monoclinic space group P21/c again, but forms its own structure type with the lattice parameters a = 753.81(5), b = 1281.92(9), c = 1276.47(9) pm and β = 106.898(3)° and Z = 4. The Cs+ cations are twelve-fold coordinated by selenium atoms and erects a three-dimensional framework of condensed [CsSe12]23− polyhedra. The Er3+ cations show seven selenium atoms as neighbors and the [ErSe7]11− polyhedra are edge-connected to form discrete dimers [Er2Se12]18−. All three structures have similar ethane-like [P2Se6]4– anions in staggered conformation with bond lengths of 219–226 pm for d(P1–P2) and 213–222 pm for d(P–Se), which connect the Cs+ and Ln3+ coordination polyhedra into three-dimensional crystal structures.

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