Structural Systematics of Rare Earth Complexes. I. Structural Characterization of Lanthanoid(III) Picrate Hydrates: Monoclinic (P21/C) (Quasi-)Dodecahydrates of the Related La → Pr and Nd → Tb Families

1994 ◽  
Vol 47 (2) ◽  
pp. 321 ◽  
Author(s):  
JM Harrowfield ◽  
WM Lu ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Type A ◽  
Water Molecules ◽  
Complex Species ◽  
X Ray ◽  
Structural Types ◽  
Group Oxygen ◽  
Group Oxygen Atom ◽  
History Of ◽  
Similar Complex

Single-crystal room-temperature X-ray studies on hydrated specimens (deposited from aqueous solutions) of the sequence of trivalent lanthanoid picrates La → Tb have shown, with certain qualifications/reservations discussed herein and in Parts III and IV following, their existence as dodecahydrates in two closely related but subtly different monoclinic P21/c structural types. Nd → Tb generally conform to a 'low-β' type: a 7.767(1) → 7.603(3), b 27.525(9) → 27.440(10), c 18.198(11) → 18.182(8) Ǻ, β 105.11(3) → 105.18(4)°, V 3712(3) → 3674(3) Ǻ3, Z = 4 formula units, while La → Pr are a 'higher-β' type: a 7.933(1) → 7.9435(9), b 26.856(6) → 26.74(1), c 18.244(6) → 18.215(2) Ǻ, β 107.96(2) → 108.238(8)°, V 3697(2) → 3675(2) Ǻ3, Z = 4 formula units; the latter form is frequently found partially desolvated toward the undecahydrate without loss of crystal integrity, as water is lost from tunnels in the lattice, with the actual hydrate stoichiometry dependent on the history of the specimen. In both sets of compounds, similar complex species [ Ln ( pic )2(OH2)6]+ are observed, with one picrate uncoordinated as counter ion, and six lattice water molecules. The lanthanoid ion is >8-coordinate, one of the coordinated picrate moieties being quasi-bidentate , with an ortho-nitro group oxygen atom having a long contact to the metal atom in both series.

Characterization of Dislocations and Micropipes in 4H n+ SiC Substrates

2008 ◽  
Vol 600-603 ◽  
pp. 333-336 ◽  
Author(s):  
Ping Wu ◽  
Murugesu Yoganathan ◽  
Ilya Zwieback ◽  
Yi Chen ◽  
Michael Dudley
Keyword(s):  
Etch Pits ◽  
Screw Dislocations ◽  
X Ray ◽  
Nitrogen Doped ◽  
Different Types ◽  
History Of ◽  
Density Analysis ◽  
Threading Defects ◽  
Edge Dislocations

Etching of 4H-SiC wafers in molten KOH as a method for micropipe and dislocation density analysis was investigated. The obtained results were correlated with those of the synchrotron white beam x-ray topography. Heavily nitrogen-doped SiC shows a significantly different etching behavior in comparison with the low-doped material. This complicates identification of different types of threading defects. In particular, it is difficult to separate Threading Screw Dislocations (TSD) from Threading Edge Dislocations (TED). Depending on the level of doping and thermal history of the crystal, some of the etch pits emerging due to the 1c screw dislocations can be as large as those due to the micropipes.

Synthesis and crystallographic studies of two new 1,3,5-triazines

2020 ◽  
Vol 76 (4) ◽  
pp. 322-327
Author(s):  
Emmanuel Blas Patricio-Rangel ◽  
Margarita Tlahuextl ◽  
Hugo Tlahuext ◽  
Antonio Rafael Tapia-Benavides
Keyword(s):  
Noncovalent Interactions ◽  
Synthesis And Characterization ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
Positional Disorder ◽  
Hydrated Salt ◽  
Symmetry Space ◽  
Symmetry Space Group

The synthesis and characterization of two new 1,3,5-triazines containing 2-(aminomethyl)-1H-benzimidazole hydrochloride as a substituent are reported, namely, 2-{[(4,6-dichloro-1,3,5-triazin-2-yl)amino]methyl}-1H-benzimidazol-3-ium chloride, C11H9Cl2N6 +·Cl− (1), and bis(2,2′-{[(6-chloro-1,3,5-triazine-2,4-diyl)bis(azanediyl)]bis(methylene)}bis(1H-benzimidazol-3-ium)) tetrachloride heptahydrate, 2C19H18ClN9 2+·4Cl−·7H2O (2). Both salts were characterized using single-crystal X-ray diffraction analysis and IR spectroscopy. Moreover, the NMR (1H and 13C) spectra of 1 were obtained. Salts 1 and 2 have triclinic symmetry (space group P-1) and their supramolecular structures are stabilized by hydrogen bonding and offset π–π interactions. In hydrated salt 2, the noncovalent interactions yield pseudo-nanotubes filled with chloride anions and water molecules, which were modelled in the refinement with substitutional and positional disorder.

scholarly journals Mineralogical Characterization of Dolomitic Aggregate Concrete: The Camarasa Dam (Catalonia, Spain)

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 117
Author(s):  
Encarnación Garcia ◽  
Pura Alfonso ◽  
Esperança Tauler
Keyword(s):  
Portland Cement ◽  
Type A ◽  
Alkali Silica Reaction ◽  
Type B ◽  
Mineralogical Characterization ◽  
Group Mineral ◽  
X Ray ◽  
Concrete Type ◽  
Further Development

The Camarasa Dam was built in 1920 using dolomitic aggregate and Portland cement with two different compositions: type A (dolomite and Portland cement) and type B (dolomite and sand-cement). The sand cement was a finely powdered mixture of dolomite particles and clinker of Portland cement. The mineralogy of concrete was studied by optical microscopy, scanning electron microscopy, and x-ray powder diffraction. Reaction of dedolomitization occurred in the two types of concrete of the Camarasa Dam, as demonstrated by the occurrence of calcite, brucite, and/or absence of portlandite. In the type A concrete, calcite, brucite, and a serpentine-group mineral precipitated as a rim around the dolomite grains and in the paste. The rims, a product of the dedolomitization reaction, protected the surface of dolomite from the dissolution process. In type B concrete, in addition to dolomite and calcite, quartz and K-feldspar were present. Brucite occurred in lower amounts than in the type A concrete as fibrous crystals randomly distributed in the sand-cement paste. Although brucite content was higher in the type A concrete, type B showed more signs of loss of durability. This can be attributed to the further development of the alkali-silica reaction in this concrete type.

Synthesis and Structural Characterization of the Mixed Ligand Complex [Cu(Hml)2(Phen)] · 2 H2O (H2ml = 2-Methyllactic Acid)

2003 ◽  
Vol 58 (1) ◽  
pp. 151-154 ◽  
Author(s):  
Rosa Carballo ◽  
Berta Covelo ◽  
Ezequiel M. Vázquez-Lópeza ◽  
Alfonso Castiñeiras ◽  
Juan Niclós
Keyword(s):  
Magnetic Measurements ◽  
Mixed Ligand Complex ◽  
Three Dimensional ◽  
Mixed Ligand ◽  
Water Molecules ◽  
Ligand Complex ◽  
X Ray ◽  
Dimensional Network ◽  
Distorted Octahedral

Abstract A new mixed-ligand complex of copper(II) with 1,10-phenanthroline and 2-methyllactate was prepared. [Cu(HmL)2(phen)] ·2H2O (where HmL = monodeprotonated 2-methyllactic acid) was characterized by elemental analysis, IR, electronic and EPR spectroscopy, magnetic measurements at room temperature, thermogravimetric analysis and X-ray diffractometry. The copper atom is in a tetragonally distorted octahedral environment and the 2-methyllactato ligand is bidentately chelating. The presence of lattice water molecules mediates the formation of a three-dimensional network.

A Molecular Chain of Four CoII Ions Stabilized by a Tris-Pyridyl/Bis-?-Diketonate Ligand

2009 ◽  
Vol 62 (9) ◽  
pp. 1130 ◽  
Author(s):  
Leoní A. Barrios ◽  
David Aguilà ◽  
Olivier Roubeau ◽  
Keith S. Murray ◽  
Guillem Aromí
Keyword(s):  
Exchange Interactions ◽  
Molecular Chain ◽  
Water Molecules ◽  
Spin Orbit Coupling ◽  
Antiferromagnetic Exchange ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bulk Magnetization ◽  
Hexadentate Ligand

The synthesis and characterization of a tris-pyridyl/bis-β-diketone molecule (H2L) is reported. This compound acts as a hexadentate ligand towards CoII to facilitate the assembly of a tetranuclear molecular chain of closely spaced metals with formula [Co4L2(MeOH)8](NO3)4 (1), which exhibits a very flat [Co4L2]4+ platform, as determined by single-crystal X-ray diffraction crystallography. Complex 1 readily exchanges axial methanol ligands with water molecules. The bulk magnetization of the resulting hydrate, 1a, shows that the metals in the [Co4L2]4+ moiety exhibit spin-orbit coupling and antiferromagnetic exchange interactions.

Synthesis, Structure and Characterization of a Novel 3D Zinc Organophosphonate

2014 ◽  
Vol 936 ◽  
pp. 915-918
Author(s):  
Hui Duan Li
Keyword(s):  
Powder Diffraction ◽  
Organic Ligand ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
One Dimensional ◽  
X Ray ◽  
Open Framework ◽  
Solvothermal Conditions

A novel zinc organophosphonate was synthesized under solvothermal conditions by using [piperazine-1,4-diyldi (methylene)] bis (phosphonic acid) as a organic ligand. Single-crystal X-ray diffraction analysis reveals that compound 1 crystallized in the triclinic space group P-1 (No. 2). Compound 1 formulated as Zn (O3PCH2NHC4H8NHCH2PO3)·H2O. Compound 1 featured a 3D open-framework. Notably, the structure of compound 1 featured one-dimensional channel in the [00 direction. Water molecules were located in these channels. Further characterizations of compound 1 have been performed, including X-ray powder diffraction, IR, ICP and CHN analyses.

Different structural types of copper(II) furan- and thiophencarboxylates: X-ray structural, EPR, spectral and magnetic analyses‡

2016 ◽  
Vol 70 (1) ◽  
Author(s):  
Petra Bertová ◽  
Vladimír Kuchtanin ◽  
Zdeňka Růžičková ◽  
Ján Moncoľ ◽  
Jozef Švorec ◽  
...  
Keyword(s):  
Synthesis And Characterization ◽  
X Ray ◽  
Structural Types

Synthesis and characterization of eight new complexes of various structural types are reported. With 5-nitro-2-furancarboxylic acid (5-NO

scholarly journals KARAKTERISASI ABU KAYU MERBAU (Intsia, spp.): PENGARUH TEMPERATUR DAN LAMA KALSINASI

2019 ◽  
Vol 15 (1) ◽  
pp. 30-38
Author(s):  
Darma Santi ◽  
Jacson Victor Morin
Keyword(s):  
Calcination Temperature ◽  
Wood Ash ◽  
Hexagonal Structure ◽  
Rhombohedral Structure ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Cubic Structure

Characterization of merbau wood ash (Intsia, spp.) due to the influence of temperature and time of calcination has been studied. The variations in calcination temperature were 500 ᴼC (as M500) and 600 ᴼC (as M600), while the variations in the duration of calcination were 1, 2, and 3 hours, noted as M1, M2, and M3, respectively. Characterization was carried out using X-ray diffraction (XRD) and spectroscopic analysis using FT-IR. XRD results identified the presence of CaCO3 species (rhombohedral structure) and K2Si4O9 species with a hexagonal structure on M500. The M600 species identified Si (cubic structure), SiO2 (cubic structure), K2Si4O9 (hexagonal structure), and CaCO3 (rhombohedral structure). In general, the calcination temperature increases the crystallinity of several compounds contained in merbau wood ash. The length of time calcination reduces the absorption peak due to the decomposition and adsorption reactions of the presence of water molecules bound to the ash material of merbau wood (Intsia, spp).

Synthesis, Structure and Characterization of Trisodium Bis[N-(2-oximinopropionyl)glycinato(3 – )-O,N,N'] Cobaltate(III) Nonahydrate

1993 ◽  
Vol 48 (3) ◽  
pp. 270-276 ◽  
Author(s):  
Igor O. Fritsky ◽  
Rostislav D. Lampeka ◽  
Victor V. Skopenko ◽  
Yury A. Simonov ◽  
Alexander A. Dvorkin ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Free Ligand ◽  
Unit Cell ◽  
Water Molecules ◽  
Amide Nitrogen ◽  
Triclinic Space Group ◽  
X Ray ◽  
Peptide Complexes ◽  
Complex Anions

A cobalt(III) complex with pyruvylglycine oxime (H3G) of composition Na3[CoG2] · 9 H2O is synthesized and investigated by means of X-ray analysis, infrared, electronic and NMR spectroscopy. The crystals are triclinic, space group P1̄, a = 15.477(5), b = 9.931(4), c = 7.773(4)Å; α = 75.60(3); β = 82.86(4); γ = 93.54(3)°; Ζ = 2. The structure was refined to final R = 0.036 for 3347 independent observed reflections. The structure consists of the complex anions, Na+ cations and water molecules. The ligands are coordinated via the deprotonated oxime and amide nitrogen and the carboxyl oxygen atoms in a meridional fashion (Co—O(carboxyl) = 1.971 and 1.947 Å; Co— N(oxime) = 1.891 and 1.909; Co— N(amide) = 1.876 and 1.866Å). The Co(III) coordination octahedron is slightly distorted; the Co—O and Co—N distances are in agreement with the data for oxime and peptide complexes of Co(III). The unit cell contains 2 enantiomeric complex anions related by a center of symmetry. The electronic, IR and NMR (1H and 13C) spectra of the complex are compared to those of the free ligand and of dipeptidato complexes of Co(III).

Structural Studies of Alkaline Earth Metal Picrates

1995 ◽  
Vol 48 (7) ◽  
pp. 1333 ◽  
Author(s):  
JM Harrowfield ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Nitro Group ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Linear Polymer ◽  
Alkaline Earth Metal ◽  
Water Molecules ◽  
X Ray ◽  
Main Group Metal ◽  
Group Oxygen ◽  
Structure Determinations

Room-temperature, single-crystal X-ray structure determinations are recorded for alkaline earth metal picrates , M( pic )2.nH2O(M = Mg, Sr , Ba ; Hpic = 2,4,6-trinitrophenol, HOC6H2(NO2)3), all crystallized from aqueous solution. Magnesium picrate ,shown to be the nonahydrate, Mg( pic )2.9H2O, forms monoclinic crystals, space group P21/c, a 15.023(3), b 6.718(4), c 26.516(2) Ǻ, β 109.55(1)°, Z = 4 f.u .,conventional R on |F| was 0.049 for No = 4062 'observed' (I > 3σ(I)) reflections. The structure, unusually among the main group metal picrates studied so far, has no coordinative interaction between the metal and the picrate anion; the complex may be formulated as [Mg(OH2)6] ( pic )2.3H2O, with the metal present as the hexaaqua species (Mg-O 2.043(2)-2.077(2)Ǻ). The picrate ions are stacked end to end, presumably as a result of charge-transfer interactions, parallel to b, with side-by-side stacks forming a sheet along ab, and successive sheets are interleaved by layers of cations and water molecules. The strontium salt is a pentahydrate , monoclinic, C2/c, a 24.515(6), b 10.142(6), c 17.932(4) Ǻ, β 98.76(2)°, Z = 8 f.u .; R was 0.046 for No 2731. The complex is a linear polymer, [(H2O)3Sr(O,O′- pic )2(μ-OH2)](∞|∞).H2O, with eight-coordinate (SrO8) strontium. The barium salt is a hexahydrate , also a linear polymer [(H2O)5Ba(O,O′-pic )( O,O′,μ-O″-pic )]∞|∞).H2O, the ten-coordinate (BaO10) barium environment comprising the five water molecules, a pair of picrates, bidentate /chelating via the phenolic oxygen and a 2-nitro group oxygen, with one of the picrates from an adjacent metal atom offering an additional 4-nitro group oxygen, this bridging successive barium atoms. The complex is triclinic, Pī , a 15.120(5), b 11.633(3), c 6.766(3) Ǻ, α 87.24(3), β 79.16(3), γ 84.88(2)°, Z = 2 f.u .; R was 0.027 for No 3904. Repeated attempts to obtain crystals of beryllium picrate suitable for an X-ray structure determination were unsuccessful.

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