The Crystal Structure of Tl2.36Sb5.98As4.59S17, the Lead-Free Endmember of the Chabournéite Homeotypic Group

ABSTRACT The crystal structure of Tl2.36Sb5.98As4.59S17, the lead-free endmember of the chabournéite homeotypic group, from the Tl-As-Sb-rich gold deposit at Vorontsovskoye (the Urals, Russia) was determined and refined to R(obs) 0.099 for 9340 unique observed X-ray reflections. The triclinic unit-cell parameters determined from single-crystal data are as follows: a = 8.63253(19) Å, b = 16.3055(7) Å, c = 21.8196(8) Å, α = 75.094 (3)°, β = 83.631(2)°, γ = 89.303 (2)°, V = 2949.18(18) Å3 (Z = 4), space group . The crystal structure is composed of (001) slabs based on PbS and SnS archetypes, arranged in regular alternation. All Sb(As) coordination polyhedra are (Sb,As)S3+2+(1 or 2) coordination pyramids, in the majority of cases with a mixed Sb-As occupancy in both slab types. Bond-length distributions were studied in detail. The zig-zag boundary between the slabs is composed of a repeating sequence of [100] Tl-Tl, Sb-Sb (1/3 substituted by As), Tl-Tl, and Tl-Sb columns. Thallium forms tricapped trigonal coordination prisms and (Sb,As) forms bicapped prisms. Differences compared to two related structures—parapierrotite and tsygankoite—are specified. Twinning of chabournéite is connected with the (imperfect) order-disorder character of the structure, which is connected with the configurations observed on slab boundaries. The structure refinement of the lead-free Tl-(Sb,As) chabournéite endmember presented in this paper is the best starting point for a restudy of all complexities of the chabournéite homeotypic group.

Crystal structure of strontium hydrogen citrate monohydrate, Sr(HC6H5O7)(H2O)

The crystal structure of strontium hydrogen citrate monohydrate has been solved using laboratory X-ray powder diffraction data, refined using both laboratory and synchrotron data, and optimized using density functional techniques. Strontium hydrogen citrate monohydrate crystallizes in space group C2/c (#15) with a = 25.15601(17), b = 10.90724(6), c = 6.37341(4) Å, β = 91.9846(6)°, V = 1747.704(12) Å3, and Z = 8. The Sr coordination and the hydrogen bonding result in a layered structure. The SrO8 coordination polyhedra share edges to form corrugated layers parallel to the bc-plane. Hydrogen bonds between the carboxylic acid groups and water molecules link the layers. Intermolecular hydroxyl–carboxyl hydrogen bonds also link the layers in a ring pattern with a graph set symbol R2,2(12). After storage for 2 years, partial re-crystallization occurred, to an as-yet unknown compound with a triclinic unit cell.

Crystal structure of a new hydrate form of the NSAID sodium diclofenac

The crystal structure is reported of sodium 2-[2-(2,6-dichloroanilino)phenyl]acetate 3.5-hydrate or tetra-μ-aqua-κ8 O:O-decaaquabis{μ3-2-[2-(2,6-dichloroanilino)phenyl]acetato-κ3 O:O:O}tetrasodium(I) bis{2-[2-(2,6-dichloroanilino)phenyl]acetate}, {[Na4(C14H10Cl2NO2)2(H2O)14](C14H10Cl2NO2)2} n , which represents a new hydrate form of the NSAID sodium diclofenac (SD). The triclinic unit cell contains one ionic compound with formula Na4(C14H10Cl2NO2)4(H2O)14, in which two symmetry-related carboxylate anions C14H10Cl2NO2 − are bonded to a centrosymmetric [Na4]4+ core cationic cluster, while the others are only hydrogen bonded to the cationic cluster. The conformation for the anions is similar to that found in other diclofenac compounds, and the [Na4(Ocarbox)2(H2O)14]4+ cluster displays an unprecedented geometry, which can be described as an incomplete dicubane cluster formed by face-sharing incomplete cubes. A complex framework of O—H...O hydrogen bonds stabilizes the crystal structure. The herein reported crystal structure for SD·3.5H2O in space group P\overline{1} is different from those previously reported for other hydrates, namely SD·4.75H2O (P21) and SD·5H2O (P21/m).

Bis(1-dodecyl-4-aza-1-azoniabicyclo[2.2.2]octane)tetraisothiocyanatocobalt(II)

The title compound, [Co(C18H37N2)2(NCS)4], consists of a cobalt(II) ion positioned on the origin of the triclinic unit cell. It is coordinated by the N atoms of two trans-oriented 1-dodecyl-4-aza-1-azoniabicyclo[2.2.2]octane (DABCO+) cations, which carry n-dodecyl chains at the non-coordinating N atoms. The distorted octahedral coordination environment of the CoII ion is completed through four N atoms of isothiocyanate ions, which are arranged within the equatorial plane. Non-classical hydrogen bonding of the types C—H...N and C—H...S between the filamentous molecules lead to the formation of layers parallel to (001).

From structure topology to chemical composition. XXVII. Revision of the crystal chemistry of the perraultite-type minerals of the seidozerite supergroup: Jinshajiangite, surkhobite, and bobshannonite

ABSTRACT The crystal structures of the three perraultite-type minerals (bafertisite group, seidozerite supergroup)—jinshajiangite from Norra Kärr, Sweden, ideally NaBaFe2+4Ti2(Si2O7)2O2(OH)2F, Z = 4; surkhobite (holotype) from the Darai-Pioz massif, Tajikistan, ideally NaBaMn4Ti2(Si2O7)2O2(OH)2F, Z = 4; and bobshannonite (holotype) from Mont Saint-Hilaire, Canada, ideally Na2KBa(Mn7Na)Nb4(Si2O7)4O4(OH)4O2, Z = 2—were refined in space group C to R1 = 2.73, 2.85, and 2.02% on the basis of 2746, 2657, and 4963 unique reflections [Fo > 4σFo], respectively. Refinement was done using data from twinned crystals (jinshajiangite: three twin components; surkhobite and bobshannonite: two twin components). The parameters of a C-centered triclinic unit cell are as follows: jinshajiangite: a = 10.720(5), b = 13.823(7), c = 11.044(6) Å, α = 108.222(6), β = 99.28(1), γ = 89.989(6)°, V = 1532.0(2.2) Å3; surkhobite: a = 10.728(6), b = 13.845(8), c = 11.072(6) Å, α = 108.185(6), β = 99.219(5), γ = 90.001(8)°, V = 1540.0(2.5) Å3; and bobshannonite: a = 10.831(7), b = 13.903(9), c = 11.149(8) Å, α = 108.145(6), β = 99.215(9), γ = 90.007(7)°, V = 1572.6(3.2) Å3. New electron microprobe data are reported for the holotype surkhobite and new IR data for jinshajiangite. In the perraultite-type structure (structure type B1BG, B – basic, BG – bafertisite group), there is one type of TS (Titanium-Silicate) block and one type of I (Intermediate) block; they alternate along c. The TS block consists of HOH sheets (H-heteropolyhedral, O-octahedral). In the O sheet, the ideal composition of the five [6]MO sites is Fe2+4apfu (jinshajiangite), Mn4apfu (surkhobite), and (Mn7Na) (bobshannonite). There is no order of Fe2+ and Mn in the O sheet. In the H sheet, the ideal composition of the two [6]MH sites is Ti2apfu (jinshajiangite, surkhobite) and Nb4apfu (bobshannonite). The four [4]Si sites are occupied solely by Si. The MH octahedra and Si2O7 groups constitute the H sheet. The TS blocks link via common vertices of MH octahedra. The I block contains AP(1,2) and BP(1,2) cation sites. In the I block of jinshajiangite and surkhobite, the AP(1) site is occupied by Ba and the AP(2) site by K > Ba; the ideal composition of the two AP(1,2) sites is Ba apfu. In the I block of bobshannonite, Ba and K are ordered at the AP(1) and AP(2) sites, Ba:K ∼ 1:1 , ideally BaK apfu. The two BP(1,2) sites are each occupied by Na > Ca, ideally Na apfu (jinshajiangite, surkhobite) and solely by Na, ideally Na2apfu (bobshannonite). There is no order of Na and Ca at the BP(1,2) sites in jinshajiangite and surkhobite [currently defined as a Ca-ordered analogue of perraultite, ideally NaBaMn4Ti2(Si2O7)2O2(OH)2F, Z = 4]. The ideal formulae of surkhobite, KBa3Ca2Na2Mn16Ti8(Si2O7)8O8(OH)4(F,O,OH)8 (current IMA formula) and of bobshannonite, Na2KBa(Mn,Na)8(Nb,Ti)4(Si2O7)4O4(OH)4(O,F)2 (current IMA formula) have been revised as follows: NaBaMn4Ti2(Si2O7)2O2(OH)2F, Z = 4 (surkhobite) and Na2KBa(Mn7Na)Nb4(Si2O7)4O4(OH)4O2, Z = 2 (bobshannonite). The revised ideal formula of surkhobite is identical to the ideal formula of perraultite and hence surkhobite should be discredited.

Di-μ-benzoato-di-μ-ethanolato-tetrakis[μ3-5-(hydroxymethyl)-2-methyl-4-(oxidomethyl)pyridin-1-ium-3-olato]tetrakis[μ3-5-(hydroxymethyl)-2-methyl-4-(oxidomethyl)pyridin-3-olato]di-μ3-oxido-heptamanganese(II,III) ethanol octasolvate

Our work in the area of synthesis of polynuclear manganese complexes and their magnetic properties led to the synthesis and crystallization of the title compound, [Mn7(C8H9NO3)4(C8H10NO3)4(C2H5O)2(C7H5O2)2O2]·8C2H5OH. Herein, we report the molecular and crystal structure of the title compound, which was synthesized by the reaction of Mn(C6H5COO)2 with pyridoxine (PNH2, C8H11NO3) followed by the addition of tetramethylammonium hydroxide (TMAOH). The core of this centrosymmetric complex is a cage-like structure consisting of six MnIII ions and one MnII ion bound together through Mn—O bonds. The compound crystallizes in hydrogen-bonded layers formed by O—H...N hydrogen bonds involving the aromatic amine group of the ligand PN2− with the neighboring O atoms from the PNH− ligand. The crystal structure has large voids present in which highly disordered solvent molecules (ethanol) sit. A solvent mask was calculated and 181 electrons were found in a volume of 843 Å3 in one void per triclinic unit cell. This is consistent with the presence of seven ethanol molecules per formula unit, which accounts for 182 electrons per unit cell. Additionally, one ethanol molecule was found to be ordered in the crystal.

Crystal structure of the thortveitite-relatedMphase, (MnxZn1–x)2V2O7(0.75

The determination of the crystal structure of theMphase, (MnxZn1–x)2V2O7(0.75 <x< 0.913), in the pseudobinary Mn2V2O7–Zn2V2O7system forx≃ 0.8 shows that the previously published triclinic unit-cell parameters for this thortveitite-related phase do not describe a true lattice for this phase. Instead, single-crystal X-ray data and Rietveld refinement of synchrotron X-ray powder data show that theMphase has a different triclinic structure in the space groupP-1 withZ= 2. As prior work has suggested, the crystal structure can be described as a distorted version of the thortveitite crystal structure of β-Mn2V2O7. A twofold superstructure in diffraction patterns of crystals of theMphase used for single-crystal X-ray diffraction work arises from twinning by reticular pseudomerohedry. This superstructure can be described as a commensurate modulation of a pseudo-monoclinic basis structure closely related to the crystal structure of β-Mn2V2O7. In comparison with the distortions introduced when β-Mn2V2O7transforms at low temperature to α-Mn2V2O7, the distortions which give rise to theMphase from the β-Mn2V2O7prototype are noticeably less pronounced.

Another step toward the solution of the real structure of zinkenite

The crystal structure of Cu-bearing zinkenite from Saint-Pons (Alpes Maritimes department, France), having idealized chemical composition Cu0.7Pb9.7Sb21.3S42, has been studied. It has a pronounced hexagonal sub-cell, with unit-cell parametersa=22.1219(11),c=4.3207(3) Å,V=1831.2(2) Å3, space groupP63,Z=1. The sub-cell crystal structure was refined toR1=0.072 on the basis of 3905 reflections withFo>4σ(Fo) and 133 refined parameters. It can be described as formed by one kind of rod, with walls of columns of (Pb/Sb)-centered polyhedra flanking both the rods and the sites located along the 63screw axis. Minor Cu is hosted in the tetrahedral voids between the rods and the walls of polyhedra. Alternatively, the crystal structure of zinkenite can be described as formed by trigonal rods, delimited by lone electron-pair micelles, and tunnels hosting (Pb/Sb) atoms. The occurrence of weak superstructure reflections points to a triclinic unit cell with parametersa=38.271(2),b=22.1219(13),c=8.6475(5) Å, α=89.931(3), β=90.030(3), γ=89.957(3)°,V=7323.6(7) Å3, space groupP1,Z=4. The twin laws making the twin lattice hexagonal have been taken into account and the crystal structure has been solved and refined. Notwithstanding the very lowR1value (R1=0.038 on the basis of 22563 reflections withFo>4σ(Fo) and 1194 refined parameters), several shortcomings, mainly due to the low diffraction quality of the available crystals, allow only the description of the main structural features of the superstructure of zinkenite, indicating the correctness of the triclinic model hypothesized by previous authors.

Crystal structure of 1-[2-(4-nitrophenyl)-4,5-diphenyl-1H-imidazol-1-yl]propan-2-ol

The title compound, C24H21N3O3, crystallizes with two unique but closely r.m.s. overlay fit = 0.215 Å) comparable molecules (1 and 2) in the asymmetric unit of the triclinic unit cell. In molecule 1, the dihedral angles between the central imidazlole ring and the benzene-ring substituents are 42.51 (9), 45.41 (9) and 56.92 (8)°, respectively. Comparable data for molecule 2 are 39.36 (10), 34.45 (11) and 60.34 (8)°, respectively. The rings at the 2-positions carryp-nitro substituents that subtend dihedral angles of 12.9 (4)° in molecule 1 and 11.7 (4)° in molecule 2 to their respective benzene ring planes. The imidazole rings also have propan-2-ol substituents on the 1-N atoms, which adopt extended conformations for the N—C—C—C chains. In the crystal, classical O—H...N hydrogen bonds combine with C—H...O, C—H...N and C—H...π(ring) hydrogen bonds and stack the molecules along thea-axis direction.

Crystal structure and physical properties of 1-methyl-3-(carboxymethyl)benzimidazolium betaine·CuBr2 in crystal and water solution

Planar CuO2Br2 complex exists in a triclinic unit cell. Single crystal EPR and MO-theory give electron spin density delocalization parameters.