On the determination of unit-cell dimensions from inaccurate powder diffraction data

Werner, Per‐Erik

doi:10.1107/s0021889876010996

Cited by 60 publications

(19 citation statements)

References 2 publications

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“…The positions of the highest d-spacing reflections were manually measured for indexing purposes. Using the autoindexing program TREOR (Werner, 1976), the crystal lattice was indexed to an orthorhombic cell a = 7.1675, b = 7.0919, c = 8.8251 A (see supplementary material*), indicating a V'2 by X/2 increase in cell size within the ab plane. This ease of lattice parameter determination from first principles is typical of time-of-flight powder diffraction experiments when the highest dspacing information is available.…”

Section: The T%phase Structurementioning

confidence: 99%

Neutron diffraction and calorimetric studies of methylammonium iodide

Yamamuro¹,

Matsuo²,

Suga³

et al. 1992

Acta Crystallogr B Struct Sci

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A powerful combination of calorimetric and highresolution neutron powder-diffraction techniques has been used to study the phase transitions in deuterated methylammonium iodide. The neutron powderdiffraction measurements have confirmed the fourfold disorder of the deuterium atoms about the (73 axis of the methylammonium ion in the tetragonal (P4/nmm) a" phase. The structure of the metastable 6 phase was determined using a novel method of chemically constrained profile refinement. It was 0108-7681/92/030329-08506.00 atoms were completely ordered in an anti-parallel manner along the b axis. Heat capacities of the a' and 8 phases of CD3ND3I were measured in the temperature range 13-303 K. A continuous ,~-type anomaly was found at the 8-a' phase transition which occurred at 164.0 K with an associated transition entropy of 8.8 J K-1 mol-i. The results are very similar to those of CH3NH3I measured previously, indicating that deuteration of the methylammonium ion does not affect the mechanism of the 6-a" phase transition of CD3ND3I.

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Section: The T%phase Structurementioning

confidence: 99%

Neutron diffraction and calorimetric studies of methylammonium iodide

Yamamuro¹,

Matsuo²,

Suga³

et al. 1992

Acta Crystallogr B Struct Sci

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“…1. X-ray diffraction peak positions of Li 2 Mn(PO 3 ) 4 /C can be successfully indexed with an orthorhombic lattice using the program TREOR [19]. The lattice parameters were determined to be a=9.426 Å, b=9.271 Å, and c=10.101 Å, which are a little larger than the value reported previously [14] but agree much better with the values recently reported by Moutataouia et al [15].…”

Section: Resultsmentioning

confidence: 93%

Synthesis, characterization, and electrochemical properties of Li2Mn1-x Fe x (PO3)4 cathode material for lithium-ion batteries

Yan

Zhao

Dong

et al. 2015

J Solid State Electrochem

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Li 2 Mn 1-x Fe x (PO 3 ) 4 (x=0, 0.2, 0.4, 0.6, 0.7) solid solution phase has been successfully prepared via solid-state reaction. The Rietveld refinement results indicate that the Li 2 Mn 1-x Fe x (PO 3 ) 4 (x=0, 0.2, 0.4, 0.6, 0.7) solid solutions with orthorhombic structure can be obtained and the lattice parameters (including a, b, c, and V) decrease with the increasing of Fe concentration. Partial substitution of manganese with iron enhances the electrochemical performance; there, the discharge-specific capacity of the samples obviously increases from 21 mAh/g for x=0 to 59 mAh/g for x=0.7, which is 85 % capacity of that one lithium removal. The cyclic voltammetric (CV) curves present the Mn 2+ /Mn 3+ redox couple situated at 4.6 and 1.8 V and Fe 2+ /Fe 3+ redox couple located at 4.3 and 2.3 V, which can be observed in cathodic and anodic sweeps. Such a low discharge potential value for M 2+ / M 3+ redox couple may be attributed to the zigzag [(PO 3 ) 1− ] n chains in this structure.

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“…We deliberately neglected the lower-symmetry systems (monclinic and triclinic) because the density of popu- lation of the observed lines is rather low, indicating a symmetry not less than orthorhombic. Satisfactory agreement for all the experimental lines was obtained for hexagonal, tetragonal and orthorhombic cells (only the cubic system failed with meaningfully small cells): to decide among the best ones purely on the basis of the various criteria proposed as indices of merit (de Wolff, 1968(de Wolff, , 1972Werner, 1976;Smith & Snyder, 1979) proved to be very difficult. However, a careful evaluation of the details of the texture displayed in the Wallace-Ward camera photographs gave a unique unit cell.…”

Section: Cell Datamentioning

confidence: 94%

A new CeO₂form obtained as oxidation product of CeO₂+SiO₂-doped hot-pressed silicon nitride

Celotti¹,

Babini²,

Bellosi³

et al. 1982

J Appl Cryst

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By using data from the Wallace & Ward [J. Appl. Cryst. (1975), 8, 255-260] cylindrical texture camera integrated with other traditional X-ray powder film techniques for very low and very high diffraction angles, a new high-temperature modification of CeO 2 was identified and indexed resulting in a trigonal or hexagonal unit cell with a = 8-36(2) and c = 10.42(2) A, (axial ratio 1.264) and Z= 16. The new phase is an oxidation product of CeO2-doped hot-pressed silicon nitride. It can be quenched to room temperature under appropriate conditions. Its stability on reheating is strictly related to its interaction with the silicate phase.

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On the determination of unit-cell dimensions from inaccurate powder diffraction data

Cited by 60 publications

References 2 publications

Neutron diffraction and calorimetric studies of methylammonium iodide

Neutron diffraction and calorimetric studies of methylammonium iodide

Synthesis, characterization, and electrochemical properties of Li2Mn1-x Fe x (PO3)4 cathode material for lithium-ion batteries

A new CeO₂form obtained as oxidation product of CeO₂+SiO₂-doped hot-pressed silicon nitride

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On the determination of unit-cell dimensions from inaccurate powder diffraction data

Cited by 60 publications

References 2 publications

Neutron diffraction and calorimetric studies of methylammonium iodide

Neutron diffraction and calorimetric studies of methylammonium iodide

Synthesis, characterization, and electrochemical properties of Li2Mn1-x Fe x (PO3)4 cathode material for lithium-ion batteries

A new CeO2form obtained as oxidation product of CeO2+SiO2-doped hot-pressed silicon nitride

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A new CeO₂form obtained as oxidation product of CeO₂+SiO₂-doped hot-pressed silicon nitride