Investigation by the use of profile refinement of neutron powder diffraction data of the geometry of the [Si2O7]6− ions in the high temperature phases of rare earth disilicates prepared from the melt in crucible-free synthesis

1994 ◽  
Vol 209 (1) ◽  
Author(s):  
A. Nørlund Christensen
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Single Crystals ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Neutron Powder Diffraction ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Neutron Powder Diffraction Data ◽  
Profile Refinement

AbstractPowders and X-ray size single crystals of the rare earth disilicates REThe high temperature modifications of LaThe high temperature modifications of HoEr

scholarly journals Superconducting Cuprates and Related Oxides. II. Profile Refinement of Neutron Powder Diffraction Data.

1990 ◽  
Vol 44 ◽  
pp. 902-906 ◽  
Author(s):  
A. Nørlund Christensen ◽  
B. Lebech ◽  
Michinobu Kato ◽  
Knut Maartmann-Moe ◽  
Yoneichiro Muto ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Neutron Powder Diffraction ◽  
Powder Diffraction Data ◽  
Superconducting Cuprates ◽  
Neutron Powder Diffraction Data ◽  
Profile Refinement

BaCeN2, ein Bariumnitridocerat(IV) mit einer Struktur vom anti-TiP-Typ / BaCeN2, a Bariumnitridocerate(IV ) with a Structure of the anti-TiP Type

1994 ◽  
Vol 49 (9) ◽  
pp. 1169-1174 ◽  
Author(s):  
Oliver Seeger ◽  
Joachim Strähle
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Neutron Powder Diffraction ◽  
Type Structure ◽  
Stoichiometric Ratio ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Neutron Powder Diffraction Data ◽  
Moisture Sensitive ◽  
Trigonal Prismatic

Reaction of Ba3N2 with CeN in the stoichiometric ratio 1:3 at 850 °C under an atmosphere of N2 followed by quenching yields air and moisture sensitive BaCeN2. The product crystallizes isotypically to β-RbScO2 with the anti-TiP type structure in the hexagonal space group P63/mmc with a = 365.06(2), c = 1266.03(3) pm, Z = 2. The structure was determined using X-ray and neutron powder diffraction data. In the structure the Ba2+ cations occupy trigonal prismatic holes with distances Ba-N = 288(1) pm while the Ce atoms are in octahedral positions with distances C e -N = 242.4(8) pm

ChemInform Abstract: Structure of Y4O(OH)9NO3 from X-Ray and Neutron Powder Diffraction Data.

ChemInform ◽  
2010 ◽  
Vol 23 (26) ◽  
pp. no-no
Author(s):  
A. N. CHRISTENSEN ◽  
M. NIELSEN ◽  
K. P. J. O'REILLY ◽  
T. WROBLEWSKI
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Neutron Powder Diffraction ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Neutron Powder Diffraction Data ◽  
Abstract Structure

Crystal and molecular structures of 2-[1-(2-aminoethyl)-2-imidazolidinylidene]-2-nitroacetonitrile (C7H11N5O2) and 2,6-diamino-5-hydroxy-3-nitro-4H-pyrazolo[1,5-a]pyrimidin-7-one monohydrate (C6H6N6O4·H2O) from X-ray, synchrotron and neutron powder diffraction data

1999 ◽  
Vol 55 (4) ◽  
pp. 554-562 ◽  
Author(s):  
V. V. Chernyshev ◽  
A. N. Fitch ◽  
E. J. Sonneveld ◽  
A. I. Kurbakov ◽  
V. A. Makarov ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Neutron Powder Diffraction ◽  
Molecular Structures ◽  
Search Procedure ◽  
Grid Search ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Neutron Powder Diffraction Data

The crystal and molecular structures of 2-[1-(2-aminoethyl)-2-imidazolidinylidene]-2-nitroacetonitrile [C7H11N5O2; space group P21/n; Z = 4; a = 7.4889 (8), b = 17.273 (2), c = 7.4073 (8) Å, β = 111.937 (6)°], (I), and 2,6-diamino-5-hydroxy-3-nitro-4H-pyrazolo[1,5-a]pyrimidin-7-one monohydrate [C6H6N6O4·H2O; space group P21/n; Z = 4; a = 17.576 (3), b = 10.900 (2), c = 4.6738 (6) Å, β = 92.867 (8)°], (II), have been determined from X-ray, synchrotron and neutron powder diffraction data using various methods. The structures were originally solved from Guinier photographs with a grid search procedure and the program MRIA using a priori information from NMR and mass spectra on the possible geometry of the molecules. Because the conformation of molecule (I) changed during the bond-restrained Rietveld refinement, solvent water was found in (II) and, moreover, as both Guinier patterns were corrupted by texture, high-resolution texture-free synchrotron data were collected at the BM16 beamline, ESRF, to confirm the original results. Using the set of |F| 2 values derived from the synchrotron patterns after full-pattern decomposition procedures, the structures of (I) and (II) were solved by direct methods via SHELXS96, SIRPOW.92 and POWSIM without any preliminary models of the molecules, and by Patterson search methods via DIRDIF96 and PATSEE with the use of rigid fragments from each of the molecules. The neutron patterns allowed (I) and (II) to be solved using the grid search procedure and correct initial models of the molecules including H atoms. The results obtained from powder patterns measured on different devices demonstrate the high level of reproducibility and reliability of various powder software and equipment, with a certain preference for synchrotron facilities.

Sign in / Sign up

Export Citation Format

Share Document