scholarly journals A NOVEL OCTAHEDRAL NIOBIUM OXYCHLORIDE CLUSTER BUILT FROM INTERCONNECTED Nb6Cl12O4 UNITS: Cs2Sc3Nb1227O8

2011 ◽  
Vol 11 (2) ◽  
pp. 109-116
Author(s):  
Fakhili Gulo
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Three Dimensional ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Stoichiometric Mixture ◽  
Orthorhombic System ◽  
X Ray ◽  
Solid State Route ◽  
Valence Electrons

A novel octahedral niobium cluster oxychloride compound, Cs2Sc3Nb12Cl27O8 was synthesized by solid-state route techniques from stoichiometric mixture of CsCl, Sc2O3, Nb, NbCl5, and Nb2O5, heated at 700 °C for two days. The crystal structure was determined by single crystal X-ray diffraction method. It crystallizes in orthorhombic system with space group of Pnma, a = 17.5206(1) Å, b = 29.6899(3) Å, c = 9.2114(1) Å, and V = 4791.63(8) Å3. The structure is based on  unit in which four oxygen ligands selectively occupy inner positions arranged in sets of three and one on opposite side of the Nb6 octahedron. Each cluster shares three apical-chlorine ligands with three adjacent clusters to form layers with topology similar to that of graphite. The cluster units are also connected to each other by both cesium and scandium atoms to form a three-dimensional framework. This compound exhibits 14 valence electrons per cluster.

scholarly journals X-ray diffraction studies of enkephalins. Crystal structure of [(4′-bromo) Phe4,Leu5]enkephalin

1984 ◽  
Vol 218 (3) ◽  
pp. 677-689 ◽  
Author(s):  
T Ishida ◽  
M Kenmotsu ◽  
Y Mino ◽  
M Inoue ◽  
T Fujiwara ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Least Squares Method ◽  
Heavy Atom ◽  
Three Dimensional ◽  
Diffraction Method ◽  
Biologically Active ◽  
Type I ◽  
X Ray Diffraction ◽  
X Ray ◽  
Relationship Of

In order to investigate the structure-activity relationship of [Leu5]- and [Met5]enkephalins, [(4′-bromo)Phe4, Leu5]-, [(4′-bromo)Phe4, Met5]- and [Met5] enkephalins were synthesized and crystallized. The crystal structure of [(4′-bromo) Phe4, Leu5]- enkephalin was determined by X-ray diffraction method using the heavy atom method and refined to R = 0.092 by the least-squares method. The molecule in this crystal took essentially the same type I' beta-turn conformation found in [Leu5]enkephalin [Smith & Griffin (1978) Science 199, 1214-1216). On the other hand, the preliminary three-dimensional Patterson analyses showed that the most probable conformations of [(4′-bromo)Phe4,Met5]- and [Met5]enkephalins are both the dimeric extended forms. Based on these insights, the biologically active conformation of enkephalin was discussed in relation to the mu- and delta-receptors.

Synthesis, spectroscopic study, and crystal structure of a new organotin(IV) selenate derivative

2018 ◽  
Vol 41 (5-6) ◽  
pp. 183-188
Author(s):  
Waly Diallo ◽  
Libasse Diop ◽  
Cheikh Abdoul Khadir Diop ◽  
Hélène Cattey ◽  
Laurent Plasseraud
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Three Dimensional ◽  
Resonance Spectroscopy ◽  
Zigzag Chain ◽  
X Ray Diffraction ◽  
Oh Groups ◽  
Orthorhombic System ◽  
X Ray ◽  
Dimensional Network

Abstract The polymeric organotin(IV) selenate complex [(Me3Sn)3(SeO4)(OH)]n (1) has been isolated as single crystals from the reaction of [(Me2NH2)2SeO4] and Me3SnCl in methanol. In the solid state, compound 1 was characterized by X-ray diffraction analysis, Fourier transform-infrared spectroscopy, and elemental analysis. 1 crystallizes in the orthorhombic system space group Pbca with a=11.0231(2) Å, b=16.3461(3) Å, c=20.9945(4) Å, α=β=γ=90°, V=3782.89(12) Å3, and Z=8. Its structure can be described as a polymeric zigzag chain based on Me3Sn moieties linked by tridentate selenate anions. Pendant (Me3Sn)2OH groups are also connected to the chain, according to a syndiotactic organization, and via Sn-O-Se bonds. Intermolecular OH···O hydrogen bonds and long Se-O···Sn distance interactions promote the association of chains together and lead to the propagation of a three-dimensional network. In addition, the behavior of 1 in solution (methanol) was also studied by multinuclear nuclear magnetic resonance spectroscopy and mass spectrometry.

Determination of Crystal Structure of Cd3(BO3)2 by Powder X-Ray Diffraction

1991 ◽  
Vol 6 (1) ◽  
pp. 28-30 ◽  
Author(s):  
Y. Laureiro ◽  
M.L. Veiga ◽  
M.L. López ◽  
S. García-Martín ◽  
A. Jerez ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Low Temperatures ◽  
Rietveld Analysis ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Orthorhombic System ◽  
X Ray ◽  
Cell Parameters

AbstractCd3(BO3)2 was prepared by a solid state reaction between B(OH)3 and Cd(OH)2 at low temperatures ranging between 523° and 623° and at a pressure of 10−4 – 10−5 Hg mm. The crystal structure has been refined by Rietveld analysis of X-ray powder diffraction data. The compound crystallizes in the orthorhombic system, space group Pnnm, Z = 2, with cell parameters of a = 5.967(5) Å, b = 4.78 (0) Å and c = 9.009(5) Å.

Synthesis and structural characterization of Ca12Ge17B8O58

2016 ◽  
Vol 71 (11) ◽  
pp. 1141-1146
Author(s):  
Sebastian Bräuchle ◽  
Klaus Wurst ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Temperature ◽  
Solid State ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Open Structure ◽  
X Ray ◽  
Tetragonal Crystal ◽  
Tetragonal Crystal System

AbstractCa12Ge17B8O58 was prepared by high-temperature solid state synthesis at 1100°C in a platinum crucible from calcium carbonate, boric acid, and germanium(IV) oxide. The compound crystallizes in the tetragonal crystal system in the space group P4̅ (No. 81) isotypically to Cd12Ge17B8O58. The structure was refined from single-crystal X-ray diffraction data: a = 15.053(8), c = 4.723(2) Å, V = 1070.2(2) Å3, R1 = 0.0151, and wR2 = 0.0339 for all data. The crystal structure of Ca12Ge17B8O58 consists of [Ge4O12]n chains composed of GeO4 tetrahedra and GeO6 octahedra. The chains are interconnected into a [Ge4O10.5]n network via corner sharing. By additional [Ge(B2O7)4]28– clusters, these units are connected to a three-dimensional [Ge17B8O58]24– framework. The open structure forms three types of tunnels with five-, six-, and seven-membered rings (MRs) along the c axis, where the Ca2+ are located.

scholarly journals Crystal structure of a new tripotassium hexanickel iron hexaphosphate

2019 ◽  
Vol 75 (3) ◽  
pp. 402-404 ◽  
Author(s):  
Said Ouaatta ◽  
Abderrazzak Assani ◽  
Mohamed Saadi ◽  
Lahcen El Ammari
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Solid State Reaction ◽  
Three Dimensional ◽  
Iron Phosphate ◽  
X Ray Diffraction ◽  
Coordination Polyhedra ◽  
X Ray ◽  
Nickel Iron ◽  
Eds Analysis

A new potassium-nickel iron phosphate, K3Ni6Fe(PO4)6, has been synthesized by solid-state reaction and structurally characterized by single-crystal X-ray diffraction and qualitative energy dispersive X-ray spectroscopy (EDS) analysis. The structure is built up by [FeO6], [PO4], and [NiO6] coordination polyhedra, which are linked to each other by edge and corner sharing to form zigzag layers parallel to the ab plane. These layers are interconnected by [PO4] tetrahedra and [NiO6] octahedra via common corners, leading to a three-dimensional framework delimiting large channels running along the [100] direction in which the K+ cations are localized.

scholarly journals Synthesis, crystal structure, spectroscopic and thermal investigations of neodymium(III) biphenyl-4,4′-dicarboxylate framework

2012 ◽  
Vol 10 (4) ◽  
pp. 1165-1174 ◽  
Author(s):  
Renata Łyszczek ◽  
Liliana Mazur
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Oxygen Atom ◽  
Solvothermal Method ◽  
3D Structure ◽  
Three Dimensional ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Investigations

AbstractThe three-dimensional complex {[Nd(bpdc)1.5(DMF)]·1.4DMF}n (DMF=N,N′-dimethylformamide, bpdc=biphenyl-4,4′-dicarboxylate) was synthesized using the solvothermal method. The crystal structure of the neodymium(III) complex has been determined by single-crystal X-ray diffraction method at 100(2) K. The polymeric structure consists of neodymium polyhedra bridged by bpdc ligands. Eight-coordinated Nd(III) atoms are surrounded by seven oxygen atoms from six bpdc moieties and one oxygen atom from the DMF molecule. The 3D structure of the complex contains two types of channels occupied by DMF molecules. Thermal analysis revealed that DMF molecules are lost in a stepwise manner. The infrared spectrum confirmed full deprotonation of acid and presence of DMF molecules in the structure.

scholarly journals An investigation of polyhedral deformation in two mixed-metal diarsenates: SrZnAs2O7and BaCuAs2O7

2015 ◽  
Vol 71 (4) ◽  
pp. 330-337 ◽  
Author(s):  
Sabina Kovač ◽  
Ljiljana Karanović ◽  
Tamara Đorđević
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
General Formula ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Open Framework ◽  
Geometrical Characteristics ◽  
Barium Copper

Two isostructural diarsenates, SrZnAs2O7(strontium zinc diarsenate), (I), and BaCuAs2O7[barium copper(II) diarsenate], (II), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. The three-dimensional open-framework crystal structure consists of corner-sharingM2O5(M2 = Zn or Cu) square pyramids and diarsenate (As2O7) groups. Each As2O7group shares its five corners with five differentM2O5square pyramids. The resulting framework delimits two types of tunnels aligned parallel to the [010] and [100] directions where the large divalent nine-coordinatedM1 (M1 = Sr or Ba) cations are located. The geometrical characteristics of theM1O9,M2O5and As2O7groups of known isostructural diarsenates, adopting the general formulaM1IIM2IIAs2O7(M1II= Sr, Ba, Pb;M2II= Mg, Co, Cu, Zn) and crystallizing in the space groupP21/n, are presented and discussed.

A MOF based on a lead(II) 2-oxido-6-methylpyridine-4-carboxylate network

2020 ◽  
Vol 75 (4) ◽  
pp. 365-369
Author(s):  
Long Tang ◽  
Yu Pei Fu ◽  
Na Cui ◽  
Ji Jiang Wang ◽  
Xiang Yang Hou ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Carboxylic Acid ◽  
Thermogravimetric Analysis ◽  
Metal Organic Framework ◽  
X Ray Diffraction ◽  
X Ray ◽  
Connected Node ◽  
Metal Organic ◽  
Solid State Fluorescence

AbstractA new metal-organic framework, [Pb(hmpcaH)2]n (1), has been hydrothermally synthesized from Pb(OAc)2 · 3H2O and 2-hydroxy-6-methylpyridine-4-carboxylic acid (hmpcaH2; 2), and characterized by IR spectroscopy, elemental and thermogravimetric analysis, and single-crystal X-ray diffraction. In complex 1, each hmpcaH− ligand represents a three-connected node to combine with the hexacoordinated Pb(II) ions, generating a 3D binodal (3,6)-connected ant network. The crystal structure of 2 was determined. The solid-state fluorescence properties of 1 and 2 were investigated.

scholarly journals Investigation of Solvatomorphism and Its Photophysical Implications for Archetypal Trinuclear Au3(1-Methylimidazolate)3

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4404
Author(s):  
Shengyang Guan ◽  
David C. Mayer ◽  
Christian Jandl ◽  
Sebastian J. Weishäupl ◽  
Angela Casini ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Density Functional ◽  
Bulk Material ◽  
Variable Temperature ◽  
Active Phase ◽  
Solvent Free ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aurophilic Interactions

A new solvatomorph of [Au3(1-Methylimidazolate)3] (Au3(MeIm)3)—the simplest congener of imidazolate-based Au(I) cyclic trinuclear complexes (CTCs)—has been identified and structurally characterized. Single-crystal X-ray diffraction revealed a dichloromethane solvate exhibiting remarkably short intermolecular Au⋯Au distances (3.2190(7) Å). This goes along with a dimer formation in the solid state, which is not observed in a previously reported solvent-free crystal structure. Hirshfeld analysis, in combination with density functional theory (DFT) calculations, indicates that the dimerization is generally driven by attractive aurophilic interactions, which are commonly associated with the luminescence properties of CTCs. Since Au3(MeIm)3 has previously been reported to be emissive in the solid-state, we conducted a thorough photophysical study combined with phase analysis by means of powder X-ray diffraction (PXRD), to correctly attribute the photophysically active phase of the bulk material. Interestingly, all investigated powder samples accessed via different preparation methods can be assigned to the pristine solvent-free crystal structure, showing no aurophilic interactions. Finally, the observed strong thermochromism of the solid-state material was investigated by means of variable-temperature PXRD, ruling out a significant phase transition being responsible for the drastic change of the emission properties (hypsochromic shift from 710 nm to 510 nm) when lowering the temperature down to 77 K.

A New X‐Ray Diffraction Method for Studying Imperfections of Crystal Structure in Polycrystalline Specimens

1951 ◽  
Vol 22 (5) ◽  
pp. 665-672 ◽  
Author(s):  
Alfred J. Reis ◽  
Jerome J. Slade ◽  
Sigmund Weissmann
Keyword(s):  
Crystal Structure ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray
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