Synthesis, X-Ray Diffraction (XRD), Differential Thermal Analysis (DTA), and Scanning Electron Microscopy (SEM) of the Alloy (CuInTe2)1-x(NbTe)x with x=0.5

A polycrystalline ingot (30mm long, 10mm diameter) of the alloy (CuInTe2)1-x(NbTe)x with x=0.5 has been produced using the melt and anneal technique and characterized by X-Ray Diffraction (XRD), Diferential Thermal Analysys (DTA) and Scanning Electron Microscopy (SEM). From XRD results, and using Rietveld refinement method, the crystal structure has been obtained indicating than this alloy crystallizes in a chalcopyrite-like structure, space group  (Nº 112), unit cell parameters a = 6.1933(2) Å, c = 12.4293(2) Å, V = 476.75(2) Å3, figures of merit Rexp= 6.7%, Rp= 7.5%, Rwp= 7.3%, and S = 1.1. DTA measurements indicate three thermal transitions at 1028, 977 and 886 K in the heating cycle, and 1016, 900 and 848 K in the cooling. The transitions at 1028 and 1016 correspond to the melting and solidification point, respectively; the transitions at 977 and 900 K are of solid to liquid+solid type, whereas the transitions at 886 and 848 K correspond to order-disorder. The melting point is incongruent. In the diffraction pattern, traces of a secondary phase are observed; this phase has been identified using SEM technique as (CuIn)0.5NbTe2. DOI: http://dx.doi.org/10.17807/orbital.v14i1.167

Synthesis and Crystal Structure of the Ordered Vacancy Compound Cu3In5Se9

This work focuses on the preparation and structural characterization of the semiconductor Cu3In5Se9, an important member of ordered vacancy compounds family, belonging to the semiconductor system I3-III5--VI9, where denotes the cation vacancy which is included in the formula to maintain the same number of cations and anions sites. This material was synthesized by the Bridgman-Stockbarger technique, and its structure was refined from powder X-ray diffraction data using the Rietveld method. Cu3In5Se9 crystallizes with tetragonal symmetry in the space group P2c (Nº 112), with a = 5.7657(1) Å, c = 11.5353(4) Å, V = 383.47(2) Å3. This ternary compound consists of a three-dimensional arrangement of distorted CuSe4 and InSe4 tetrahedral connected by common faces. In this structure, each Se atom is coordinated by four cations located at the corners of a slightly distorted tetrahedron, and each cation is tetrahedrally bonded to four anions. Cu3In5Se9 is related to the p-type CuInSe2 and n-type CuIn3Se5 semiconductor compounds, which are being used in the preparation of high-efficiency solar cells. DO: http://dx.doi.org/10.17807/orbital.v13i3.156

Synthesis, X-Ray Diffraction (XRD), Differential Thermal Analysis (DTA), and Scanning Electron Microscopy (SEM) of the Alloy (CuInTe2)1-x(NbTe)x with x=0.5

A polycrystalline ingot (30mm long, 10mm diameter) of the alloy (CuInTe2)1-x(NbTe)x with x=0.5 has been produced using the melt and anneal technique and characterized by X-Ray Diffraction (XRD), Diferential Thermal Analysys (DTA) and Scanning Electron Microscopy (SEM). From XRD results, and using Rietveld refinement method, the crystal structure has been obtained indicating than this alloy crystallizes in a chalcopyrite-like structure, space group  (Nº 112), unit cell parameters a = 6.1933(2) Å, c = 12.4293(2) Å, V = 476.75(2) Å3, figures of merit Rexp= 6.7%, Rp= 7.5%, Rwp= 7.3%, and S = 1.1. DTA measurements indicate three thermal transitions at 1028, 977 and 886 K in the heating cycle, and 1016, 900 and 848 K in the cooling. The transitions at 1028 and 1016 correspond to the melting and solidification point, respectively; the transitions at 977 and 900 K are of solid to liquid+solid type, whereas the transitions at 886 and 848 K correspond to order-disorder. The melting point is incongruent. In the diffraction pattern, traces of a secondary phase are observed; this phase has been identified using SEM technique as (CuIn)0.5NbTe2. DOI: http://dx.doi.org/10.17807/orbital.v14i1.167

Synthesis and structural characterization of magnetic semiconductor silver iron germanium selenide (Ag2FeGeSe4)

The quaternary semiconductor compound Ag2FeGeSe4, belonging to the system I2-II-IV-VI4 and synthesized by the meltand anneal technique, was structurally characterized by Rietveld refinement of the powder X-ray diffraction data. Thiscompound crystallizes in the orthorhombic space group Pmn21, Z = 4, with unit cell parameters a = 7.6478(1) Å, b =6.5071(1) Å, c = 6.4260(1) Å, and V = 319.79(1) Å3, in a wurtzite-stannite arrangement with a Cu2CdGeS4-type structure.The Debye temperature (D) estimated for this compound was 194 K

Synthesis, thermal studies and crystal structure of 4-aminopyridinium semi-oxalate hemihydrate

The title compound has been synthesized by grinding in an agate mortar. Its structure was characterized by TGA-DSC studies and single-crystal X-ray diffraction. This compound crystallize in the monoclinic system with space group C2/c, Z = 4, and unit cell parameters a = 16.109(2) Å, b = 5.748(7) Å, c = 20.580(3) Å, β = 107.36(1)°. The salt, C2HO4 -.C5H7N+.0.5 H2O, is an ionic ensemble assisted by hydrogen bonds established between 4-aminopyridinium cations, oxalate anions and water molecules. The three components thus construct a supramolecular assembly with a three-dimensional hydrogen bonded framework

rac-1-Acetyl-5-benzyl-2-thioxoimidazolidin-4-one

In the title compound, C12H12N2O2S, the mol­ecules have a wing-like conformation, with a distance of 3.797 (2) Å between the centroids of the five- and six-membered rings. In the crystal structure, mol­ecules are linked by N—H⋯O hydrogen bonds, forming infinite one-dimensional zigzag chains, running along [001], with a C(4) graph-set motif

Estructura cristalina y molecular de diacuo-bis-{μ2-N-(4- metilbenzoil)glicina-O,O}-bis{N-(4-metilbenzoil)glicinato- O,O’} de disodio dihidratado

Se presenta la síntesis y caracterización estructural del polímero de coordinación: diacuo-bis-{μ2-N-(4-metilbenzoil)glicina-O,O}-bis{N-(4-metilbenzoil)glicinato-O,O’} de disodio dihidratado (C60H66N6Na2O20*2H2O). La reacción se llevó a cabo en proporción 2:1 de N-(4 metilbenzoil)glicina con Hidróxido de Sodio en una mezcla etanol:agua 1:1. Los cristales obtenidos se caracterizaron por espectroscopia FT-IR, difracción de Rayos-X de cristal único. El compuesto cristaliza en una celda triclínica con grupo espacial P1̅ (N°2) y parámetros de celda: a= 6.947(3)Å, b= 7.857(3)Å, c=20.114(7)Å, α=89.948(9)°, β= 83.351(1)° y γ=75.535(9)°. El sodio coordina con dos moléculas de N-(4-metilbenzoil)glicina, dos iones N-(4-metilbenzoil)glicinato y una molécula de agua, por ello exhibe una geometría de bipirámide trigonal distorsionada. El compuesto forma cadenas infinitas a lo largo del eje b las cuales se unen por interacciones de enlace de hidrógeno N—H···O y O—H···O. Las cadenas se apilan entre sí en la dirección [001] y se estabilizan por interacciones C—H···π y π···π.The synthesis and structural characterization of the coordination polymer: disodiumdiaqua-bis-{N-(4-methylbenzoyl)glycin-O,O}-bis-{N-(4ethylbenzoyl)glycinate- O,O’} dihydrate (C60H66N6Na2O20*2H2O) is presented. The reaction was carried out in a 2:1 ratio of N-(4-methylbenzoyl)glycine with Sodium Hydroxide in an ethanol:water 1:1 mixture. The crystals obtained were characterized by FT-IR spectroscopy and single crystal X-Ray. The compound crystallizes in a triclinic cell with space group P1̅ (N°2) and cell parameters: a= 6.947(3)Å, b= 7.857(3)Å, c=20.114(7)Å, α=89.948(9)°, β= 83.351(1)° and γ=75.535(9)°. Sodium coordinates with two N-(4-methylbenzoyl)glycine molecules, two N-(4-methylbenzoyl)glycinate ions and a water molecule, thus exhibiting distorted trigonal bipyramid geometry. The compound forms infinite chains along the b-axis which are joined by interactions N—H···O and O—H···O hydrogen bond type. The chains are stacked together in the direction [001] and stabilized by interactions C—H···π and π···π

Estudio de un indicador natural. Extracción y caracterización de curcumina a partir de los rizomas de cúrcuma cultivada en lagunillas estado Mérida, Venezuela

La extracción de compuestos de origen natural es una de las industrias en mayor crecimiento debido a los beneficios que presentan frente a sus análogos de origen sintético. En esta investigación se extrajo el principal compuesto coloreado de los rizomas de la cúrcuma (Curcuma longa L.): Curcumina (C₂₁H₂₀O₆) (1E,6E)-1,7-bis(4-hidroxi-3-metoxifenil)-1,6-heptadieno-3,5-diona, con un rendimiento del 3.42% tras 8 horas de extracción, utilizando un sistema de extractor soxhlet con solventes orgánicos (hexano y etanol). La separación y purificación se realizó por cromatografía de capa fina y de columna, usando como fase móvil una mezcla de cloroformo- hexano 3:2. El colorante fue caracterizado por análisis espectroscópico de infrarrojo (IR) y ultravioleta visible (UV-Vis), además de su estudio en la sensibilidad de viraje como indicador ácido base.The extraction of naturally occurring compounds is one of the fastest growing industries because of the benefits that have against its synthetic analogues. In this research the main compound colored rhizome of turmeric (Curcuma longa L.) is extracted: Curcumin (C₂₁H₂₀O₆)(1E,6E)-1,7-bis(4-hydroxy-3- methoxyphenyl)-1,6-heptadiene-3,5-dione, in a yield of 3.42% after 8 hours of extraction using Soxhlet extractor system with organic solvents (hexane and ethanol). Separation and purification was performed by thin layer chromatography and column using as mobile phase a mixture of chloroform-hexane 3:2. The dye was characterized by spectroscopic analysis of visible ultraviolet (UV-Vis) and infrared (IR), in addition to his studio in steering sensitivity as acid-base indicator

Evidence of a new ordered vacancy crystal structure in the compound Cu3In7Te12

The crystal structure of the ordered vacancy compound (OVC) Cu3In7Te12 is analyzed using powder X-raydiffraction data. It is found that this OVC crystallizes with a chalcopyrite-related structure, in the tetragonalspace group P 4 2c (Nº 112), with unit cell parameters and volume a = 6.1720(2) Å, c = 12.3597(8) Å, and V= 470.83(4) Å3. The Rietveld refinement of 28 instrumental and structural parameters led to Rp = 9.27 %, Rwp= 10.30 %, Rexp = 6.95% and S = 1.48, for 4501 step intensities and 130 independent reflections, respectively.This compound is isostructural with Cu3In7Se12, and has a defect adamantane structure.Keywords: semiconductors, ordered vacancy compounds, crystal structure, X-ray diffraction, Rietveld

Estructura cristalina y molecular de un nuevo pseudopolimorfo del ácido 4-metilhipúrico

En este trabajo se presenta la estructura cristalina de un nuevo pseudopolimorfo de ácido 4 metilhipúrico, obtenido por molienda y reflujo en medio básico. La determinación estructural a partir de difractometría de cristal único indica que la unidad asimétrica, conformada por dos moléculas del ácido y dos moléculas de agua, cristaliza en un sistema triclínico con grupo espacial P (No.2) y parámetros de celda: a= 6.947(3)Å, b= 7.857(3)Å, c=20.114(7)Å, α=89.948(9)°, β= 83.351(1)°, γ=75.535(9)°. El empaquetamiento cristalino del ácido 4-metilhipúrico di hidratado, está estabilizado por enlaces de hidrógeno del tipo O—H···O y N—H···O, donde las moléculas de agua juegan un papel fundamental, ya que actúa como un puente entre los dímeros molécula A-molécula B del ácido a lo largo de la dirección [010]. La estructura cristalina y características del empaquetamiento de este pseudopolimorfo se comparan con los polimorfos I y II de ácido 4-metilhipúrico.In this work we present the crystalline structure of a new pseudopolymorph of 4-methylhippuric acid, obtained by grinding and reflux in basic medium. The structural determination from single crystal diffractometry indicates that the asymmetric unit, formed by two acid molecules and two water molecules, crystallizes in a triclinic system with a space group P (No.2) and cell parameters: a= 6.947(3)Å, b= 7.857(3)Å, c=20.114(7)Å, α=89.948(9)°, β= 83.351(1)°, γ=75.535(9)°. The crystal packing of 4-methylhippuric di hydrated, is stabilized by of O—H···O and N—H···O hydrogen bonds type, where the water molecules play a fundamental role, as it acts as a bridge between the dimer molecule A-molecule B of the acid along the [010] direction. The crystal structure and packaging characteristics of this pseudopolymorph are compared with the polymorphs I and II of 4 methylhippuric acid