STEREOCHEMISTRY OF ARSENIC: PART XII. BIS(DIPHENYLARSENIC) OXIDE

1963 ◽  
Vol 41 (12) ◽  
pp. 2983-2987 ◽  
Author(s):  
W. R. Cullen ◽  
J. Trotter
Keyword(s):  
Unit Cell ◽  
The Other ◽  
Space Group ◽  
Bond Lengths ◽  
Valency Angle

Crystals of bis(diphenylarsenic) oxide are monoclinic, with four molecules in a unit cell of dimensions a = 11.48, b = 30.2, c = 5.97 Å, β = 93.8°, space group P21/n. The structure has been determined from projections along the a and c axes, using Fourier and difference syntheses. The As—O—As angle is 137°, the increase from the normal oxygen valency angle probably being a result of pπ—dπ bonding involving arsenic 4d orbitals. The As—O distance is 1.67 Å, and all the other bond lengths and angles are normal. The orientations of the substituent phenyl groups have been determined.

scholarly journals Darstellung und Struktur des Bicyclo-[4.4.0]-1.4.6.9-tetraazadecans C6H14N4 Preparation and Structure of Bicyclo-[4,4,0]-l,4,6,9-tetraazadecane C6H14N4

1978 ◽  
Vol 33 (8) ◽  
pp. 881-883 ◽  
Author(s):  
Wolfgang May ◽  
Hans Georg von Schnering
Keyword(s):  
Condensation Reaction ◽  
Weak Acid ◽  
Unit Cell ◽  
The Other ◽  
Formula Unit ◽  
Acid Interaction ◽  
Space Group ◽  
Bond Lengths ◽  
The Mean

Abstract By the weak acid interaction of polymeric phosphanes the condensation of ethylendi-amine yields in a small amount bicyclo-[4,4,0]-1,4,6,9-tetraazadecane C6H14N4. The compound crystallizes triclinic in the space group P1̅ with a = 841.6 pm, b - 463.6 pm, c = 529.2 pm, a= 109.05°, β= 108.35°, γ = 84.13° and Z= 1 formula unit per unit cell. The two condensed six-membered rings have chair conformations. The mean N-C bond lengths are 146.0 pm, the bridging C-C bond is 150.3 pm, whereas the other C-C bonds are 155.1 pm. Structure and condensation reaction are discussed.

STEREOCHEMSTRY OF ARSENIC: PART III. o-PHENYLENEDIARSINE OXYCHLORIDE

1962 ◽  
Vol 40 (6) ◽  
pp. 1113-1117 ◽  
Author(s):  
W. R. Cullen ◽  
J. Trotter
Keyword(s):  
Symmetry Axis ◽  
Van Der Waals ◽  
Membered Ring ◽  
Unit Cell ◽  
The Other ◽  
Van Der Waals Interactions ◽  
Chlorine Atoms ◽  
Space Group ◽  
Bond Lengths ◽  
Aromatic Character

Crystals of o-phenylenediarsine oxychloride, C6H4As2Cl2O, are monoclinic with four molecules in a unit cell of dimensions a = 14.50, b = 8.38, c = 7.66 Å, β = 105.8°, space group C2/c. The structure has been determined from projections along the b and c axes. Each molecule is situated on a 2-fold symmetry axis and is planar except for the chlorine atoms, which lie one on either side of the plane of the other atoms. The values of the bond lengths and valency angles have been obtained. Abnormal valency angles at the arsenic and oxygen atoms are the result of their presence in the five-membered ring, and the unusual stability of the molecule in spite of these angles can be interpreted in terms of aromatic character, involving dπ–pπ bonding. The intermolecular separations correspond to normal van der Waals interactions.

Quaternäre Strontium-Kupfer(I)-Lanthanoid(III)-Selenide mit Cer und Praseodym: SrCuCeSe3 und SrCuPrSe3, ein ungleiches Geschwisterpaar / Quaternary Strontium Copper(I) Lanthanoid(III) Selenides with Cerium and Praseodymium: SrCuCeSe3 and SrCuPrSe3, Unequal Brother and Sister

2004 ◽  
Vol 59 (9) ◽  
pp. 985-991 ◽  
Author(s):  
Sabine Strobel ◽  
Thomas Schleid
Keyword(s):  
Single Crystals ◽  
Coordination Number ◽  
Unit Cell ◽  
Structural Relationship ◽  
The Other ◽  
Space Group ◽  
Lattice Constants ◽  
The Third ◽  
Other Hand ◽  
Third Dimension

Quaternary strontium copper(I) lanthanoid(III) selenides are formed by the oxidation of elemental strontium, copper and the corresponding lanthanoid with selenium. Orange to red needle-shaped single crystals of SrCuPrSe3 and SrCuCeSe3 have been synthesized by heating mixtures of Sr, Cu, Pr / Ce and Se with CsI as a flux in evacuated silica tubes to 800°C for 7 d. Both compounds crystallize orthorhombically in space group Pnma with four formula units per unit cell, but with unlike lattice constants (a = 1097.32(6), b = 416.51(2), c = 1349.64(8) pm for SrCuPrSe3 and a = 846.13(5), b = 421.69(2), c = 1663.42(9) pm for SrCuCeSe3) and therefore different structure types. The Pr3+ cations in SrCuPrSe3 are surrounded octahedrally by six Se2− anions forming chains of edge-sharing [PrSe6]9− octahedra that are joined by common vertices. Together with [CuSe4]7− tetrahedra they form [CuPrSe3]2− layers piled up parallel (001). Between those layers the Sr2+ cations are coordinated by seven Se2− anions in the shape of capped trigonal prisms linking the structure in the third dimension. On the other hand in SrCuCeSe3 the Ce3+ cations as well as the Sr2+ cations adopt a coordination number of seven. Since the bonding distances between cerium and selenium match with those of strontium and selenium the two crystallographically independent sites of these cations are occupied statistically by Ce3+ and Sr2+ with equal ratios. Nevertheless, there is a close structural relationship between SrCuPrSe3 and SrCuCeSe3. Similar to SrCuPrSe3 where Cu+ and Pr3+ cations together with Se2− anions form [CuPrSe3]2− layers parallel (001), the Cu+ cations and [(Ce1/Sr1)Se7]11.5− polyhedra in SrCuCeSe3 build strongly puckered layers which are connected by (Ce2)3+/(Sr2)2+ cations. The copper selenium part in both compounds correlates as well, with [CuSe4]7− tetrahedra linked by common vertices to form [CuSe3]5− chains running along [010].

Thiosemicarbazide complexes of mercury (II) halides

1978 ◽  
Vol 56 (19) ◽  
pp. 2526-2529 ◽  
Author(s):  
Chung Chieh ◽  
Laura P. C. Lee ◽  
Cecilia Chiu
Keyword(s):  
The Other ◽  
Free Molecule ◽  
Space Group ◽  
Bond Lengths ◽  
Strong Band ◽  
Ir And Raman ◽  
Lattice Modes ◽  
Neighboring Molecule

Dibromobis(thiosemicarbazide)mercury(II), HgBr2(tsc)2, is isostructural with dichlorobis-(thiosemicarbazide)mercury(II). The crystal is orthorhombic with a = 8.825(9), b = 8.587(11), c = 15.939(22) Å, Z = 4, space group Pbcn. Some bond lengths and angles are: Hg—Br = 2.860(4) Å, Hg—S = 2.45(1) Å, C—S = 1.76(4) Å and [Formula: see text]. In both HgCl2(tsc)2 and HgBr2(tsc)2, the configuration of the coordinated thiosemicarbazide (tsc) is the same as that of the free molecule. The ir and Raman (R) spectra for the complexes and tsc in the region 300–1600 cm−1 are very similar. The strong band at 800 (807 R) cm−1 in the tsc due to v(C—S) is shifted to 773 (796 R), 777 (796 R), and 660 (680 R) cm−1 for HgCl2−(tsc)2, HgBr2(tsc)2, and HgCl2(tsc) correspondingly. A strong band at 368 (R) cm−1 present uniquely for HgCl2(tsc) can be assigned to v(Hg—N), The halides in HgX2(tsc)2 are bonded to one mercury(II) ion and weakly bridged to a neighboring molecule with Hg … Cl = 3.250(3) Å and Hg…Br = 3.436(4) Å. As a result, two Raman bands due to Hg—X are expected. For HgCl2(tsc)2, the two Raman bands occur at 236 and 166 cm−1, whereas for HgBr2(tsc)2, one was observed at 190 cm−1 but the other was masked by lattice modes. In HgCl2(tsc), the two Hg—Cl bonds are different and bands at 220 and 190 cm−1 are assigned to v(Hg—Cl)t.

Isolation and structure of an 18-membered macrocycle containing two diselenide linkages and its precursor

2019 ◽  
Vol 75 (3) ◽  
pp. 336-341
Author(s):  
Saravanan Raju ◽  
Ray J. Butcher ◽  
Harkesh B. Singh
Keyword(s):  
Unit Cell ◽  
Amino Groups ◽  
Space Group ◽  
Macrocyclic Ring ◽  
Bond Lengths

The structures of the 18-membered diselenide-linked macrocycle 10,27-di-tert-butyl 11,28-dioxo-2,3,19,20-tetraselena-10,12,27,29-tetraazapentacyclo[28.4.0.04,9.013,18.021,26]tetratriaconta-1(30),4(9),5,7,13,15,17,21,23,25,31,33-dodecaene-10,27-dicarboxylate, C36H34N4O6Se4, and its precursor di-tert-butyl 2,2′-[diselane-1,2-diylbis(2,1-phenylene)]dicarbamate, C22H28N2O4Se2, are reported. The precusor to the macrocycle contains two tert-butyl phenylcarbamate arms connected to a diselenide group, with Se—C and Se—Se bond lengths of 1.914 (4) and 2.3408 (6) Å, respectively. The macrocycle resides on a crystallographic center of inversion in space group P\overline{1} with one molecule in the unit cell (Z′ = 1 \over 2). It contains an 18-membered macrocyclic ring with two diselenide linkages. In this macrocycle, there are two free and two protected amino groups.

Formamidinhim-Hexachloroferrat(III) Synthese und Kristallstruktur / Formamidinium-Hexachloroferrate(III) Synthesis and Crystal Structure

1985 ◽  
Vol 40 (3) ◽  
pp. 443-446 ◽  
Author(s):  
Udo Demant ◽  
Elke Conradi ◽  
Ulrich Müller ◽  
Kurt Dehnicke
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
The Other ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
X Ray ◽  
Positional Disorder ◽  
Lattice Constants ◽  
Bond Lengths

[HC(NH2)2]3FeCl6 was obtained together with other products from the reaction of S4N4 with HCl in H2CCl2 in the presence of FeCl3. Its crystal structure was determined from X-ray diffraction data (473 independent observed reflexions, R = 0.047). Lattice constants: a = 961.6, c = 876.4 pm; tetragonal, space group P42/m, Z = 2. Of the two crystallographically independent formamidinium ions HC(NH2)2⊕, one exhibits positional disorder; the other one has C-N bond lengths of 128 pm. The FeCl63⊖ ions have symmetry C2h, but the deviation from Oh is small.

N-TrimethylsilyMminotriphenylphosphoran-Kupfer(II)-chlorid, [Me3 SiNPPh3 · CuCl 2 ]2 Synthese und Kristallstruktur / N-Trimethylsilyl-iminotriphenylphosphorane Copper(II) Chloride, [Me3 SiNPPh3 · CuCl 2] 2 Synthesis and Crystal Structure

1988 ◽  
Vol 43 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Dieter Fenske ◽  
Eberhard Böhm ◽  
Kurt Dehnicke ◽  
Joachim Strähle
Keyword(s):  
Crystal Structure ◽  
Coordination Number ◽  
Structure Determination ◽  
Ir Spectrum ◽  
Title Compound ◽  
Unit Cell ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
Bond Lengths ◽  
Moisture Sensitive

Abstract The title compound has been prepared by the reaction of N-trimethylsilyl-iminotriphenylphos-phorane with copper(II) chloride in boiling CCl4 /C2H5OH, and forms moisture sensitive crystals, which are green in transmittance and black in reflexion. [Me3SiNPPh3 · CuCl2 ] 2 was characterized by its IR spectrum as well as by a crystal structure determination (4197 observed, independent reflexions, R = 0.049). The lattice dimensions are at 20 °C: a = 1102.7. b = 1407.3. c = 1560.2 pm; β = 94.27°; space group P21/n with two formula units in the unit cell. The complex consists of centrosymmetric, dimeric molecules with a planar Cu2 Cl2 ring (Cu-CI bond lengths 229 and 231 pm). A terminally bonded CI atom (Cu-CI = 221 pm) and the N atom of the Me3SiNPPh3 ligand (Cu-N = 198.5 pm) complete the coordination number four of the nearly planar surroundings of the Cu atoms.

THE CRYSTAL STRUCTURE OF 1,4-DIBROMONAPHTHALENE

1961 ◽  
Vol 39 (8) ◽  
pp. 1574-1578 ◽  
Author(s):  
J. Trotter
Keyword(s):  
Crystal Structure ◽  
Detailed Examination ◽  
Unit Cell ◽  
Asymmetric Unit ◽  
Space Group ◽  
Bond Lengths ◽  
Sufficient Precision ◽  
Molecular Dimensions

Crystals of 1,4-dibromonaphthalene are monoclinic with eight molecules in a unit cell of dimensions a = 27.45, b = 16.62, c = 4.09 Å; β = 91.9°; space group P21/a The high proportion of bromine in the crystal probably precludes location of the carbon atoms with sufficient precision to give accurate molecular dimensions, and it has therefore not been considered worth while proceeding beyond the detailed examination of the projection along the short c-axis. There are two molecules in the asymmetric unit, and the solution of the structure from hk0 Patterson and Fourier projections has indicated that these two molecules are related, at least in projection, by a pseudo center of symmetry. The projected bond distances indicate significant deviations of the bromine atoms from the aromatic plane. Approximate values of the bond lengths in the molecule have been deduced from the projected distances and estimated orientation angles.

Barium-Triel-Mercuride BaMxHg4-x und Ba3MxHg11-x (M=Ga, In, Cd) / Barium Triel Mercurides BaMxHg4-x and Ba3MxHg11-x (M =Ga, In, Cd)

2013 ◽  
Vol 68 (4) ◽  
pp. 307-322 ◽  
Author(s):  
Marco Wendorff ◽  
Caroline Röhr
Keyword(s):  
Ternary System ◽  
Theoretical Study ◽  
Structure Type ◽  
Unit Cell ◽  
Partial Ordering ◽  
Space Group ◽  
Bond Lengths ◽  
Type Orthorhombic ◽  
Stability Ranges ◽  
Phase Width

The systematic experimental and bond-theoretical study of the phase width of the BaAl4 structure type in the ternary system BaIn4- BaHg4 shows that this structure type is stable up to BaIn1:7Hg2:3 (tetragonal, tI10, space group I4=mmm, a=474.2(3), c=1228.7(9) pm, R1=0.0529). The planar 44 layers (M(2) site) are preferentially formed by In, whereas Hg occupies the tips (M(1) site) of the [M(1)M(2)4] square pyramids. The layers of the pyramids are connected via short M(1)-M(1) dumbbells (bonds a). The analysis of the calculated band structures of BaIn2Hg2 in comparison to BaIn4 and RbIn4 shows that contributions of Ba-d states (which are missing for RbIn4) and Hg-d states (which are missing in the pure indides) are significant. The respective compound with the smaller triel gallium (Hg-richest phase: BaGa1:9Hg2:1, tetragonal, oI40, space group I41=amd, a=671.3(2), c=2220.4(8) pm, Z =8, R1=0.0641) forms a new superstructure of the BaAl4 structure with a partial ordering of three statistically occupied mixed Ga=Hg positions. The 44 nets are formed by an intermediate proportion of Ga=Hg. The tips of the pyramids are alternately formed by a Ga- and an Hg-rich position leading to smaller and larger bond lengths a’ and a”, respectively, between the tip atoms and, consequentely, a puckering of the 44 net. The two Hg-rich 3 : 11 compounds Ba3InHg10 and Ba3CdHg10 (orthorhombic, oI28, space group Immm, a=513.96(8)=511.50(2), b=993.8(2)=991.54(3), c=1500.7(3)=1499.26(5) pm, Z =2, R1=0.0619=0.0482) crystallize in the La3Al11 structure type, which is also observed for K3Hg11 and is closely related to the BaAl4 type: The square pyramidal nets are corrugated leading to a triplication of the BaAl4 unit cell along one of the tetragonal axes. In each third subcell the tips of adjacent pyramids are directly fused, this position being occupied exclusively by In and Cd. With the smaller triel gallium, the 3 : 11 compound Ba3Ga0:2Hg10:8 crystallizes in the Ba3ZnHg10 structure type (orthorhombic, oP28, space group Pmmn, a=709.36(4), b=1707.96(9), c=630.78(4) pm, Z =2, R1=0.0342). The structure contains folded layers of flat rectangular Ga=Hg pyramids, leaving large channels at the folds, in which Ba(1) and Hg(2) atoms alternate. The formation and stability ranges of 1 : 4, 3 : 11 and related 5 : 19 trieles/mercurides are discussed taking geometric, electronic and M13=Hg ,coloring‘ aspects into account.

The crystal structures of CeSiO4 and Ca2Ce8(SiO4)6O2

2000 ◽  
Vol 15 (4) ◽  
pp. 234-238 ◽  
Author(s):  
J. M. S. Skakle ◽  
C. L. Dickson ◽  
F. P. Glasser
Keyword(s):  
Hydrothermal Synthesis ◽  
Nuclear Waste ◽  
Structure Type ◽  
Unit Cell ◽  
Apatite Structure ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths ◽  
Zircon Structure

Two new solubility-limiting phases relevant to nuclear waste disposal are reported, namely CeSiO4 and Ca2Ce8(SiO4)O2, produced by hydrothermal synthesis at 180 °C. X-ray diffraction data are presented for both compounds. Rietveld refinement was performed for each of these phases. CeSiO4 was confirmed to be a zircon structure type, with space group I41/amd, unit cell type="bold">abold=6.9564(3), type="bold">cbold=6.1953(4) Å. Bond lengths for SiO4 are in excellent agreement with published values; Ce4+ is coordinated to eight oxygen atoms with four regular and four short bonds. Ca2Ce8(SiO4)O2 was shown to have an apatite structure, with space group P63/m and unit cell type="bold">abold=9.4343(3), type="bold">cbold=6.8885(4) Å. The unit cell and bond lengths were found to be slightly smaller than would be expected from other lanthanide-containing analogs; possible reasons for this are discussed.

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