scholarly journals Twinning, Superstructure and Chemical Ordering in Spryite, Ag8(As3+0.50As5+0.50)S6, at Ultra-Low Temperature: An X-Ray Single-Crystal Study

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 286
Author(s):  
Luca Bindi ◽  
Marta Morana
Keyword(s):  
Single Crystal ◽  
Point Of View ◽  
New Mineral ◽  
Orthorhombic Symmetry ◽  
Temperature Structure ◽  
Crystal Chemical ◽  
Space Group ◽  
X Ray ◽  
Symmetry Space ◽  
Symmetry Space Group

Spryite (Ag7.98Cu0.05)Σ=8.03(As5+0.31Ge0.36As3+0.31Fe3+0.02)Σ=1.00S5.97, and ideally Ag8(As3+0.5As5+0.5)S6, is a new mineral recently described from the Uchucchacua polymetallic deposit, Oyon district, Catajambo, Lima Department, Peru. Its room temperature structure exhibits an orthorhombic symmetry, space group Pna21, with lattice parameters a = 14.984(4), b = 7.474(1), c = 10.571(2) Å, V = 1083.9(4) Å3, Z = 4, and shows the coexistence of As3+ and As5+ distributed in a disordered fashion in a unique mixed position. To analyze the crystal-chemical behaviour of the arsenic distribution at ultra-low temperatures, a structural study was carried out at 30 K by means of in situ single-crystal X-ray diffraction data (helium-cryostat) on the same sample previously characterized from a chemical and structural point of view. At 30 K, spryite still crystallizes with orthorhombic symmetry, space group Pna21, but gives rise to a a × 3b × c superstructure, with a = 14.866(2), b = 22.240(4), c = 10.394(1) Å, V = 3436.5(8) Å3 and Z = 4 (Ag24As3+As5+Ge4+S18 stoichiometry). The twin laws making the twin lattice simulating a perfect hexagonal symmetry have been taken into account and the crystal structure has been solved and refined. The refinement of the structure leads to a residual factor R = 0.0329 for 4070 independent observed reflections [with Fo > 4σ(Fo)] and 408 variables. The threefold superstructure arises from the ordering of As3+ and (As5+, Ge4+) in different crystal-chemical environments.

Dicobaltoarsenat -(CoAsO7) -Baugruppen im Cobaltoxid-Tellurat Co6O2[T eO4(CoAsO5)2] / Dicobaltoarsenate - (CoAsO7) - Groups in the Cobalt Oxide Tellurate Co6O2[TeO4(CoAsO5)2]

1997 ◽  
Vol 52 (5) ◽  
pp. 643-646 ◽  
Author(s):  
M. Staack ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Cobalt Oxide ◽  
Structure Type ◽  
Solid State Reactions ◽  
Orthorhombic Symmetry ◽  
X Ray ◽  
Group D ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract The compound Co6O2 [TeO4(CoAsO5)2] has been prepared by solid state reactions. Single crystal X -ray techniques led to orthorhombic symmetry, space group D 182h-Cmca, a = 6.020(1), b = 23.763(5), c = 8.841(2) Å , Z = 4. The new structure type contains the hitherto unknown cobaltoarsenate group CoAsO7, oxidic oxygen connected exclusively to cobalt, and TeO6 octahedra.

Zur Kenntnis des Kupfer-Oxid-Arsenats Cu4O(A sO4)2 / On the Copper Oxide Arsenate Cu4O(AsO4)2

1996 ◽  
Vol 51 (9) ◽  
pp. 1279-1282 ◽  
Author(s):  
M. Staack ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Copper Oxide ◽  
Single Crystal ◽  
Copper Ions ◽  
Space Group ◽  
X Ray ◽  
Different Types ◽  
Symmetry Space ◽  
Symmetry Space Group ◽  
Anionic Part

The copper oxide arsenate Cu4O(AsO4)2 has been prepared and investigated by single crystal X-ray techniques. The compound crystallizes with triclinic symmetry, space group C1i-P1̄, a = 6.4148(7), b = 7.6549(5), c = 8.2241(7) Å, α = 98.52(1), β = 112.39(1), 7 = 98.38(1)°, Z = 2. Cu4O(AsO4)2 is isotypic to Cu4(PO4)2O . Copper ions on one of the four specified sites show nearly planar coordination by O2- and may be assigned to the anionic part of the crystal structure. One of the nine different types of oxygen atoms is coordinated by copper exclusively. The compound is therefore classified as an oxide arsenate.

Darstellung und Strukturbeschreibung von NaCa3 Mn(V2O7)(V3O10) / Preparation and Structure of NaCa3Mn(V2O7)(V3O10)

1998 ◽  
Vol 53 (5-6) ◽  
pp. 507-511 ◽  
Author(s):  
R. Rettich ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Argon Atmosphere ◽  
Statistical Distribution ◽  
The Other ◽  
Space Group ◽  
X Ray ◽  
Point Position ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract Single crystals of NaCa3 Mn(V2O7)(V3O10) have been prepared by crystallization from flux in argon atmosphere. X-Ray single crystal methods led to triclinic symmetry, space group C1i - P 1̄, a = 6.8798(9), b = 6.902(1), c = 15.480(2) Å, α = 87.39(1), β = 85.32(1), γ = 86.25(2) °, Z = 2. The compound belongs to the rare trivanadates showing V2O7 and V3O10 groups incorporated into a NaCaMn/O framework. One point position of the cations is occupied by Ca2+, three by Na+ and Ca2+ in a statistical distribution and a fourth one by Mn2+. The surrounding of Mn2+ and the statistically occupied position M(3) are octahedra, the other metal positions are centers of capped trigonal prisms.

Zur Kristallstruktur von ( Cu ,Mn )3,66Mo3O12/On the Crystal Structure of (Cu ,Mn)3,66Mo3O12

1996 ◽  
Vol 51 (3) ◽  
pp. 447-449 ◽  
Author(s):  
O. Sedello ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Orthorhombic Symmetry ◽  
Space Group ◽  
X Ray ◽  
Group D ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract Single crystals of (Cu,Mn)3.66Mo3O12 have been prepared in sealed copper tubes. X-ray investiga­tions lead to orthorhombic symmetry, space group D2h16-Pnma, a = 5.1541(9), b = 10.788(2), c = 18.114(3)) Å , Z = 4. (Cu,Mn)3.66Mo3O12 is iso­typic to NaCo2.31Mo3O12 and (Cu,Co)3.75Mo3O12 with split positions for two of the metals.

The low-temperature form of calcium gold stannide, CaAuSn

2014 ◽  
Vol 70 (8) ◽  
pp. 773-775 ◽  
Author(s):  
Qisheng Lin ◽  
John D. Corbett
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Single Crystal ◽  
Diffraction Analysis ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Symmetry Space ◽  
High Temperature Polymorph ◽  
Symmetry Space Group

The EuAuGe-type CaAuSn phase has been synthesized and single-crystal X-ray diffraction analysis reveals that it has an orthorhombic symmetry (space groupImm2), witha= 4.5261 (7) Å,b= 7.1356 (11) Å andc= 7.8147 (11) Å. The structure features puckered layers that are connected by homoatomic Au—Au and Sn—Sn interlayer bonds. This structure is one of the two parent structures of its high-temperature polymorph (ca873 K), which is an intergrowth structure of the EuAuGe- and SrMgSi-type structures in a 2:3 ratio.

Zur Kenntnis von SrCo2V2O8 und SrCo2(AsO4)2 / On SrCo2V2O8 and SrCo2(AsO4)2

1994 ◽  
Vol 49 (7) ◽  
pp. 923-926 ◽  
Author(s):  
D. Osterloh ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Single Crystal ◽  
Tetragonal Symmetry ◽  
Space Group ◽  
X Ray ◽  
Symmetry Space ◽  
Symmetry Space Group

SrCo2V2O8 (I) and SrCo2(As04)2 (II) were prepared by crystallization from melts and investigated by X-ray single crystal technique. (I) is isotypic to the SrNi2V2O8-type and crys­tallizes with tetragonal symmetry, space group C124v-I41cd, a = 12.267: c = 8.424 Å: Z = 8. (II) is isotypic to the lately found SrNi2(PO4)2, space group C1i-P1̅, a = 5.713; b = 6.903; c = 9.417 Å: a = 110.48; β = 101.43; γ = 99.13°, Z = 2.

Zur Kenntnis des Oxocuprats (Cu,Co)3,75Mo3O12 / On the Oxocuprate (C u,Co)3,75Mo3O12

1995 ◽  
Vol 50 (5) ◽  
pp. 707-711 ◽  
Author(s):  
H. Szillat ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
The Other ◽  
Rectangular Prism ◽  
Orthorhombic Symmetry ◽  
Space Group ◽  
X Ray ◽  
Group D ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract Single crystals of (Cu,Co)3,75Mo3O12 have been prepared by recrystallization from melts and investigated by X-ray diffractometer techniques. The compound crystallizes with orthorhombic symmetry, space group D162h-Pnma, a = 5.092(1), b = 10.624(3), c = 17.804(4) Å, Z = 4 and is isotypic to NaCo2.31Mo3O12. The crystal structure is discussed and it is shown, that the trigonal prismatically coordinated copper positions are occupied in a different manner. One of the alternate sites is beside the centre of the prisms, and the other one is shifted towards one of the faces of the rectangular prism. This detail may be interpreted by assigning the valance states CuI and CuII. The MO6 octahedra are occupied statistically by copper and cobalt.

Neue Einsichten zur Stabilisierung des Hulsit-Strukturtyps am Beispiel von MnII,2MnIII(BO3)O2 und MnIISrMnIII(BO3)O3 / New Insights into the Stabilization of the Hulsite Structure During Crystal Structure Determination of MnII2MnIII(BO3)O2 and MnIISrMnIII(BO3)O2

1996 ◽  
Vol 51 (10) ◽  
pp. 1433-1438 ◽  
Author(s):  
Anne Utzolino ◽  
Karsten Bluhm
Keyword(s):  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Oxygen Coordination ◽  
Octahedral Oxygen ◽  
Group D ◽  
Symmetry Space ◽  
Symmetry Space Group

The compounds MnII2MnIII(BO3)O2 (I) and MnIISrMnIII(BO3)O2 (II) were prepared by using a B2O3 flux technique. Single crystals were investigated by X-ray diffraction. I showed orthorhombic symmetry, space group D92h - Pbam (No. 55), a = 926.0; b = 1241.5; c = 304.96pm ; Z = 4 and II monoclinic symmetry, space group C12h - P2/m (No. 10), a = 1107.5; b = 311.04; c = 542.93 pm, β = 95,10(2)°; Z = 2. MnII2MnIII(BO3)O2 i is isotypic with the mineral Ludwigite while MnnIISrMnmIII(BO3)O2 is isostructural with the mineral Hulsite. In the structure of MnII2Mnlll(BO3)O2 (I) all metal point positions showed octahedral oxygen coordination, one point position is occupied by Mn3+ . The structure of Mnll2Sr2Mnlll2(BO3)2O4 (II) contains five octahedrally coordinated metal sites, three of them statistically occupied by Mn2+ or Mn 3+ and Sr2+. The incorperation of Sr2+ seems to be responsible for the Hulsite structure. Both structures contain isolated, trigonal planar BO3 units and oxygen atoms that are not coordinated to boron.

Ein [Ba(Ca,Mn)O6]-Gerüst mit eingelagerten V-O-V-Gruppen in der Kristallstruktur von Ba(Ca0.6Mn0.4)V2O7 /A [Ba(Ca,Mn)O6] Framework with Incorporated V-O-V Groups in the Crystal Structure of Ba(Ca0.6Mn0.4)V2O7

1997 ◽  
Vol 52 (7) ◽  
pp. 785-789 ◽  
Author(s):  
R. Rettich ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Vanadium Oxide ◽  
Single Crystals ◽  
Orthorhombic Symmetry ◽  
Space Group ◽  
X Ray ◽  
Group D ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract Single crystals of Ba(Ca0.6Mn0.4)V2O7 have been prepared by crystallization from melts. X-ray investigations revealed a new quaternary vanadium oxide of the type BaMV2O7. The M positions are occupied statistically by Ca2+ and Mn2+. The compound crystallizes with orthorhombic symmetry, space group D2h16-Pnma, a = 15.429(2), b - 5.7005(12), c = 7.364(2) Å, Z = 4. The crystal structure can be interpreted as a [Ba(Ca,Mn)O6] network with incorporated V-O- V groups. Considering the nearest O2- neighbours of the incorporated vanadium, the V-O-V groups are complemented to give V2O7 divanadate units. Ba(Ca0.6Mn0.4)V2O7 is isotypic to BaMV2O7 (M=Ca,Cd) but not to BaMnV2O7.

Röntgenstrukturanalyse von zwei Verbindungen des Kupfertyps BaMLn2O5 (M = Zn, Ln = Sm, Tm) und von BaSmAIZn3O7 / X-Ray Analysis of Two Compounds of the Copper Type BaMLn2O5 (M=Zn, Ln=Sm, Tm) and of BaSmAlZn3O7

1997 ◽  
Vol 52 (4) ◽  
pp. 546-548 ◽  
Author(s):  
Ch. Rabbow ◽  
S. Panzer ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Metal Coordination ◽  
Orthorhombic Symmetry ◽  
Space Group ◽  
X Ray ◽  
Group D ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract Kupfertyps BaMLn2O5 (M=Zn, Ln=Sm, Tm) und von BaSmAIZn3O7 X-Ray Analysis of Two Compounds of the Copper Type BaMLn2O5 (M=Zn, Ln=Sm, Tm) and of BaSmAlZn3O7 The barium zinc lanthanoide oxides BaZnSm2O5 (I) and BaZnTm2O5 (II) crystallize in the BaCuLn2O3 copper type with orthorhombic symmetry, space group D162h,Pnma, (I)a = 12.575(2), b = 5.804(1), c = 7.198(1) Å and (II): a = 12.258(2), b = 5.684(1), c = 7.010(2) Å, Z = 4. Zinc shows square pyramidal oxygen coordina­ tion, but the strong elongation of the CuO5 pyramid in the copper type is missing. BaSmAlZn3O7 crystallizes in the space group C46V-P63mc, a = 6.346(1), c = 10.237(3) Å, Z = 2. The metal coordination of oxygen and the shifts of the ratio Al : Zn at the sites (6c) and (2a) depending on the size of the lanthanoid ions are discussed.

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