STRUCTURAL CHARACTERIZATION OF CO-PRECIPITATED  Cd1-xZnxS:Cu CRYSTALS

Structural characterization of Cd 1-x Zn x S : Cu solid solutions were carried out with 0≤x≤1. XRD studies have revealed that the compounds are polycrystalline in nature having either Hexagonal (wurtzite) or Cubic (Zincblende) structure irrespective of their composition. Also the compounds have shown the most preferred reflections due to the plane [101] of CdS(H) and [111] of ZnS(C) in addition to other prominent reflections. The various structural parameters such as lattice constant, average internal stress, micro strain, dislocaion density, grain size, and preferred orientation were correlated with the composition. The lattice constant decreased linearly with the increase in Zn concentration. The sign of internal stress indicated elongational and compressional natures corresponding to hexagonal and cubic phases of CdS respectively. The variation of micro strain appeared to be conjugate when compared to grain size variation, and the variation of dislocation density with the composition showed a higher dislocation density till x=0.4 and then decreased till x=0.8 and then increased. The degree of preferred orientation in mixed Cd 1-x Zn x S : Cu crystals as observed by the maximum peak intensity of CdS(H) and ZnS(C) reflection showed that the degree of preferred orientation remained almost constant till x=0.6 and then increased. The results were explained on the basis of different phases of the compound and the defects related to Zn atoms.

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Chemical and Structural Characterization of Maize Stover Fractions in Aspect of Its Possible Applications

Materials ◽

10.3390/ma14061527 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1527

Author(s):

Magdalena Woźniak ◽

Izabela Ratajczak ◽

Dawid Wojcieszak ◽

Agnieszka Waśkiewicz ◽

Kinga Szentner ◽

...

Keyword(s):

Structural Characterization ◽

Biogas Production ◽

Structural Parameters ◽

C:N Ratio ◽

Crystallinity Index ◽

Degree Of Crystallinity ◽

Cellulose Content ◽

X Ray Diffraction ◽

Maize Stover

In the last decade, an increasingly common method of maize stover management is to use it for energy generation, including anaerobic digestion for biogas production. Therefore, the aim of this study was to provide a chemical and structural characterization of maize stover fractions and, based on these parameters, to evaluate the potential application of these fractions, including forbiogas production. In the study, maize stover fractions, including cobs, husks, leaves and stalks, were used. The biomass samples were characterized by infrared spectroscopy (FTIR), X-ray diffraction and analysis of elemental composition. Among all maize stover fractions, stalks showed the highest C:N ratio, degree of crystallinity and cellulose and lignin contents. The high crystallinity index of stalks (38%) is associated with their high cellulose content (44.87%). FTIR analysis showed that the spectrum of maize stalks is characterized by the highest intensity of bands at 1512 cm−1 and 1384 cm−1, which are the characteristic bands of lignin and cellulose. Obtained results indicate that the maize stover fraction has an influence on the chemical and structural parameters. Moreover, presented results indicate that stalks are characterized by the most favorable chemical parameters for biogas production.

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Crystallographic and structural characterization of heterometallic platinum compounds Part VII. Heterohepta- and heterooctanuclear clusters

Open Chemistry ◽

10.1515/chem-2015-0035 ◽

2014 ◽

Vol 13 (1) ◽

Author(s):

Milan Melnik ◽

Peter Mikuš ◽

Clive E. Holloway

Keyword(s):

Structural Characterization ◽

Structural Parameters ◽

Bond Distance ◽

Point Of View ◽

Platinum Compounds ◽

Metal Atoms ◽

Platinum Clusters ◽

Structural Point

AbstractThis review classifies and analyzes over fifty heterohepta- and heterooctanuclear platinum clusters. There are eight types of metal combinations in heteroheptanuclear: Pt6M, Pt5M2, Pt4M3, Pt3M4, Pt2M5, PtM6, Pt3Hg2Ru2 and Pt2Os3Fe2. The seven metal atoms are in a wide variety of arrangements, with the most common being one in which the central M atom (mostly M(I)) is sandwiched by two M3 triangles. Another arrangement often found is an octahedron of M6 atoms asymmetrically capped by an M atom. The shortest Pt-M bond distances (non-transition and transition) are 2.326(1) Å (M = Ga) and 2.537(6) Å (M = Fe). The shortest Pt-Pt bond distance is 2.576(2) Å.In heterooctanuclear platinum clusters there are eight types of metal combinations: Pt6M2, Pt4M4, Pt3Ru5, Pt2M6, PtM7, Pt2W4Ni2, PtAu6Hg and PtAu5Hg2. From a structural point of view, the clusters are complex with bicapped octahedrons of eight metal atoms prevailing. The shortest Pt-M bond distances (non-transition and transition) are 2.651(3) Å (M = Hg) and 2.624(1) Å (M = Os). The shortest Pt-Pt bond distance is 2.622(1) Å. These values are somewhat longer than those in the heteroheptanuclear clusters. Several relationships between the structural parameters were found, and are discussed and compared with the smaller heterometallic platinum clusters

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Characterization of crystal lattice constant and dislocation density of crack-free GaN films grown on Si(111)

Applied Surface Science ◽

10.1016/j.apsusc.2010.07.073 ◽

2010 ◽

Vol 257 (4) ◽

pp. 1161-1165 ◽

Cited By ~ 22

Author(s):

Jijun Xiong ◽

Jianjun Tang ◽

Ting Liang ◽

Yong Wang ◽

Chenyang Xue ◽

...

Keyword(s):

Dislocation Density ◽

Crystal Lattice ◽

Lattice Constant ◽

Crystal Lattice Constant

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Characterization and Alumina Leachability of 12CaO·7Al2O3with Different Holding Times

Advances in Materials Science and Engineering ◽

10.1155/2014/730616 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 3

Author(s):

Hui-lan Sun ◽

Bo Wang ◽

Jian-xin Zhang ◽

Shu-feng Zong

Keyword(s):

Grain Size ◽

Surface Morphology ◽

Lattice Constant ◽

Preferred Orientation ◽

Holding Time ◽

Synthesis Time ◽

Rate Of Increase ◽

Average Grain Size ◽

Long Time ◽

Scherrer Formula

The effect of synthesis time on phase compositions, lattice constant, average grain size, preferred orientation, and surface morphology of 12CaO·7Al2O3synthesized at 1500°C was analyzed by XRD and SEM. The results indicate that the main phase of samples synthesized is 12CaO·7Al2O3when holding time is over 30 min. The lattice constant increases and the preferred orientation decreases as synthesis time prolongs. The average grain size of samples is about 59 nm calculated by Scherrer formula, and it does not change with synthesis time. The synthesis time affects the micromorphology of samples greatly. There are more and bigger holes in samples synthesized for long time. The aspects mentioned above cause the alumina leaching ratio of 12CaO·7Al2O3to increase with the prolonging of synthesis time, but the rate of increase drops.

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Crystallographic and structural characterization of heterometallic platinum complexes Part V. Heteropentanuclear complexes

Open Chemistry ◽

10.2478/s11532-013-0382-5 ◽

2014 ◽

Vol 12 (3) ◽

pp. 283-306 ◽

Cited By ~ 2

Author(s):

Milan Melník ◽

Peter Mikuš ◽

Clive Holloway

Keyword(s):

Structural Characterization ◽

Structural Parameters ◽

Bond Distance ◽

Platinum Complexes ◽

Trigonal Bipyramidal ◽

Metal Atoms ◽

Independent Molecules

AbstractThis review classifies and analyzes over eighty heteropentanuclear Pt complexes. There are eight types of metal combinations: Pt4M, Pt3M2, Pt2M3, PtM4, Pt3MM′, Pt2M2M′, PtM2M′2 and PtM3M′. The five metal atoms are in a wide variety of arrangements: trigonal-bipyramidal (most common), square-pyramidal, spike-triangular, butterfly, cubane, linear and one unique. Platinum bonds to a variety of triad partner metal atoms, soft, through borderline to hard. The shortest Pt-M bond distances for non-transition and transition M are 2.406(4) Å (M = Ge) and 2.30(1) Å (M = Co). The shortest Pt-Pt bond distance is 2.580(1) Å. Several relationships between the structural parameters were found and are discussed. Several complexes exist in two isomeric forms and others contain two crystallographically independent molecules. Both the isomers as well as independent molecules are examples of distortion isomerism.

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Expert System for Structural Characterization of Phyllosilicates: II. Application to Mixed-Layer Minerals

Clay Minerals ◽

10.1180/claymin.1994.029.1.05 ◽

1994 ◽

Vol 29 (1) ◽

pp. 39-45 ◽

Cited By ~ 4

Author(s):

V. A. Drits ◽

A. Plançon

Keyword(s):

Expert System ◽

Mixed Layer ◽

Structural Characterization ◽

Structural Parameters ◽

Margin Of Error ◽

Xrd Patterns

AbstractThe expert system described in the first part of this paper has been applied to the identification of mixed-layer phyllosilicates (mica-smectite, mica-vermiculite, chlorite-smectite, chlorite-vermiculite, chlorite-swelling chlorite, chlorite-mica, chlorite-talc, kaolinite-smectite, talc-smectite), and to the determination of their structural parameters (Reichweite, R, and proportions of constituting layers, Wi). The expert system has been run utilizing the data extracted from (1) experimental XRD patterns for which structural parameters had been evaluated by comparison with calculated patterns, or (2) patterns calculated using pre-selected values of the structural parameters. In all cases examined, the expert system provided correct conclusions concerning the identification of a mixed-layer phyllosilicate and the value of the Reichweite, while the abundances of the component layers were evaluated with a margin of error usually <5%.

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Framework Stoichiometry and Electrical Conductivity of Si-Ge Based Structure-I Clathrates

MRS Proceedings ◽

10.1557/proc-626-z13.2 ◽

2000 ◽

Vol 626 ◽

Cited By ~ 1

Author(s):

Ganesh K. Ramachandran ◽

Paul F. McMillan ◽

Jianjun Dong ◽

Jan Gryko ◽

Otto F. Sankey

Keyword(s):

Electrical Conductivity ◽

Thermal Decomposition ◽

Electronic Properties ◽

Lattice Constant ◽

Structural Characterization ◽

Periodic Table ◽

Preliminary Results ◽

Tetrahedral Sites ◽

Semiconducting Behavior

ABSTRACTWe report the synthesis and structural characterization of two Structure I clathrates in the KSi and Rb-Si systems. The alkali-Si clathrates are fully stoichiometric at the framework sites, i.e., devoid of framework vacancies. This is in sharp contrast to the analogous K-Ge, Rb-Ge and Rb-Sn, Cs-Sn systems, where vacancies are formed at one-third of the crystallographic 6c tetrahedral sites. This is rationalized in terms of Zintl-Klemm rules to remove the tetrahedral atom of its hypervalency. The contrasting behavior is understood in terms of weaker Tt-Tt (Tt – tetrelide, Si, Ge, Sn) bonding as one descends the periodic table, and results in poorly metallic conductivities for vacancy-free K7Si46 and Rb6Si46, but semiconducting behavior of K8Ge44. The observation suggests tuning of the electronic properties of Tt clathrates by substitution of (Si,Ge,Sn) on framework sites, for thermoelectric applications. We describe preliminary results designed to synthesize “mixed” Si-Ge clathrate structures. Thermal decomposition of K2SiGe results in formation of a Structure I clathrate with mixing of Si and Ge on framework sites. The lattice constant ao = 10.523(6) Å, is intermediate between those of K8Si46 and K8Ge44.

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Effect of deposition temperature on the structural and optical properties of chemically prepared nanocrystalline lead selenide thin films

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.3.50 ◽

2012 ◽

Vol 3 ◽

pp. 438-443 ◽

Cited By ~ 40

Author(s):

Anayara Begum ◽

Amir Hussain ◽

Atowar Rahman

Keyword(s):

Thin Films ◽

Dislocation Density ◽

Optical Absorption ◽

Crystallite Size ◽

Lattice Constant ◽

Deposition Temperature ◽

Structural Parameters ◽

Lead Selenide ◽

Complexing Agent ◽

X Ray

Nanocrystalline lead selenide (PbSe) thin films were prepared on glass substrates by a chemical bath deposition method, using sodium selenosulfate (Na2SeSO3) as a source of Se2− ions, and lead acetate as a source of Pb2+ ions. Trisodium citrate (TSC) was used as a complexing agent. PbSe films were prepared at various deposition temperatures while the pH value was kept fixed at 11, and the effect on the resulting film properties was studied by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and optical absorption studies. The structural parameters, such as the lattice constant (a), crystallite size (D), dislocation density (ρ) and microstrain (ε) were evaluated from the XRD spectra. It was found that average crystallite size, as calculated from Scherrer’s formula, increased from 23 to 33 nm as the deposition temperature was varied from 303 to 343 K. The dislocation density and microstrain were found to vary inversely with the crystallite size, whereas the lattice constant was found to increase with an increase in crystallite size. The optical absorption spectra of the nanocrystalline PbSe films showed a blue shift, and the optical band gap (E g ) was found to increase from 1.96 to 2.10 eV with the decrease in crystallite size.

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Crystallographic and structural characterization of heterometallic platinum compounds part IV: heterotetranuclear clusters

Open Chemistry ◽

10.2478/s11532-013-0320-6 ◽

2013 ◽

Vol 11 (12) ◽

pp. 1902-1953 ◽

Cited By ~ 3

Author(s):

Milan Melník ◽

Peter Mikuš ◽

Clive Holloway

Keyword(s):

Structural Characterization ◽

Structural Parameters ◽

Platinum Compounds ◽

Metal Atoms ◽

Platinum Clusters

AbstractThis review includes over two hundred heterotetranuclear platinum clusters. The clusters are of the compositions Pt3M, Pt3M2, PtM3, Pt′2MM′, PtM2M′ and PtMM′M”. There are twenty five different M atoms (transition and non-transition) as a partner(s) of platinum. The four metal atoms are found in a tetrahedral, planar-rhombohedral, butterfly, spited-triangular, cubane, eight — and oligo-membered rings and a unique structures. There is wide variety of the ligands from uni to- undecadentate, with the most common P and C donor sites. The shortest Pt-M (transition) versus Pt-M (non-transition) bond distances are 2.4833(8)Å (M=Pd) vs. 2.4365(5)Å (Ge). Several relationships between the various structural parameters were found and are discussed.

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Compositional and Structural Characterization of Heterostructure InGaN-Based Light-Emitting Diode by High Resolution X-Ray Diffraction

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.620.22 ◽

2012 ◽

Vol 620 ◽

pp. 22-27 ◽

Cited By ~ 1

Author(s):

Ahmad Hadi Ali ◽

Ahmad Shuhaimi ◽

Hassan Zainuriah ◽

Yushamdan Yusof

Keyword(s):

High Resolution ◽

Dislocation Density ◽

Structural Characterization ◽

Light Emitting Diode ◽

X Ray Diffraction ◽

Rocking Curve ◽

Light Emitting ◽

X Ray ◽

Multi Quantum Well

This paper focuses on the compositional and structural characterization of InGaN-based light-emitting diode (LED) using high resolution x-ray diffraction (HRXRD) system. The LED was epitaxially grown on Si (111) substrate that comprises of In0.11Ga0.89N multi-quantum-well (MQW) active layer. Phase analysis 2θ-scan proved the composition of GaN (0002) and (0004) at 34.63oand 72.98o, respectively. Rocking curveφ-scan showed six significant peaks of the hexagonal GaN structures with consistent angular gaps of ~60o. From x-ray rocking curve (XRC)ω-scan, screw and mix dislocation density is found as 2.85 × 109cm-2, while pure edge dislocation density is found as 2.23 × 1011cm-2.

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