scholarly journals Low temperature structural studies of zinc substituted copper ferrite using synchrotron X-ray powder diffraction

2015 ◽  
Author(s):  
W. Nowicki ◽  
J. Darul ◽  
A. M. T. Bell
Keyword(s):  
Low Temperature ◽  
Powder Diffraction ◽  
Copper Ferrite ◽  
Structural Studies ◽  
X Ray

Crystal structure of potassium tetraperoxomolybdate (VI) K2[Mo(O2)4]

2005 ◽  
Vol 20 (3) ◽  
pp. 203-206 ◽  
Author(s):  
M. Grzywa ◽  
M. Różycka ◽  
W. Łasocha
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Crystal Structure Refinement ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters

Potassium tetraperoxomolybdate (VI) K2[Mo(O2)4] was prepared, and its X-ray powder diffraction pattern was recorded at low temperature (258 K). The unit cell parameters were refined to a=10.7891(2) Å, α=64.925(3)°, space group R−3c (167), Z=6. The compound is isostructural with potassium tetraperoxotungstate (VI) K2[W(O2)4] (Stomberg, 1988). The sample of K2[Mo(O2)4] was characterized by analytical investigations, and the results of crystal structure refinement by Rietveld method are presented; final RP and RWP are 9.79% and 12.37%, respectively.

New data for lansfordite

1982 ◽  
Vol 46 (341) ◽  
pp. 453-457 ◽  
Author(s):  
R. J. Hill ◽  
J. H. Canterford ◽  
F. J. Moyle
Keyword(s):  
Absorption Spectrum ◽  
Low Temperature ◽  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Room Temperature ◽  
X Ray ◽  
Infra Red ◽  
Bicarbonate Solutions

AbstractEuhedral crystals of the low-temperature mineral lansfordite, MgCO3 · 5H2O, have been prepared from saturated magnesium bicarbonate solutions at temperatures below 10°C. The crystals are monoclinic P21/a with a = 12.4758(7), b = 7.6258(4), c = 7.3463(6)Å, β = 101.762(6)°, V = 684.24Å3, Dcalc. = 1.693 g cm−3, Dobs. = 1.70(1) g m−3. At room temperature, the crystals slowly effloresce to produce pseudomorphs of nesquehonite, MgCO3 · 3H2O. Dehydration is complete at 300°C, with decarbonation taking place in the interval to 560°C. A new X-ray powder diffraction pattern is presented, and details of the infra-red absorption spectrum are discussed.

Low Temperature Phase of NaOD

1986 ◽  
Vol 41 (1-2) ◽  
pp. 283-285 ◽  
Author(s):  
T. J. Bastow ◽  
D. T. Amm ◽  
S. W. Segel ◽  
R. D. Heyding
Keyword(s):  
Low Temperature ◽  
Powder Diffraction ◽  
Temperature Phase ◽  
X Ray ◽  
New Phase ◽  
Low Temperature Phase

The existence of a new phase of NaOD below 160 K is reported. NQR, NMR and DTA spectra are given and preliminary X-ray powder diffraction measurements are discussed.

Influence of Trimethylsilyl Substituents on Primary C - O Bond Lengths at the b-Position: Results from Low-Temperature X-Ray Structural Studies

1997 ◽  
Vol 50 (9) ◽  
pp. 927 ◽  
Author(s):  
Alison J. Green ◽  
William Issa ◽  
Jonathan M. White
Keyword(s):  
Low Temperature ◽  
Ester Bond ◽  
Structural Studies ◽  
Structural Effects ◽  
X Ray ◽  
Bond Lengths

The β-trimethylsilyl substituent in 2-trimethylsilylethyl p-nitrobenzoate (12b) and 2-trimethylsilylethyl 2,4-dinitrobenzenesulfenate (12c) leads to significant lengthening of the C(alkyl)–O(ester) bond. Lengthening of the Si-CH2 distance in the more electronegative ester (12c) relative to (12b) is also observed. These structural effects are consistent with the presence of σC-Si–σ* C-O interactions.

Structural studies of Fe doped Bi2Mo3O12catalysts using neutron and X-ray powder diffraction

2008 ◽  
Vol 23 (1) ◽  
pp. 33-38
Author(s):  
Y. Z. Cheng ◽  
M. M. Wu ◽  
J. Peng ◽  
X. L. Xiao ◽  
Z. X. Li ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Structural Studies ◽  
X Ray

Structure of TlSr2PrCu207−x by Rietveld analysis

1994 ◽  
Vol 9 (3) ◽  
pp. 194-199
Author(s):  
Hoong-Kun Fun ◽  
Ping Yang ◽  
Rusli Othman ◽  
Tsong-Jen Lee ◽  
Chiou-Chu Lai ◽  
...  
Keyword(s):  
Low Temperature ◽  
Crystalline Structure ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Goodness Of Fit ◽  
Rietveld Analysis ◽  
Crystal Data ◽  
X Ray ◽  
Tetragonal System

The crystalline structure of new TlSr2PrCu207−x was obtained at room temperature (300 K) and low temperature (100 K) from X-ray powder diffraction with CuKα radiation using Rietveld analysis. TlSr2PrCu207−x has an isotypical structure with TlBa2CaCu207 (1212). At 300 K, crystal data: Tl0.864Sr2PrCu2O6.75, Mr=727.811, the tetragonal system, P4/mmm, a =3.85404(5) Å, c = 12.1046(2) Å, V=179.80 Å3, Z=1, Dx =6.7218 g cm−3, μ =1143.922 cm−1 (λ = 1.54051 Å), F(000)=317.0, the structure was refined with 28 parameters to Rwp=5.29%, Rp = 3.65% for 3551 step intensities and Rb=7.40%, Rf=639% for 155 peaks, “goodness of fit” 5=3.05. At 100 K, crystal data: Tl0.858Sr2PrCu2O6.61, Mr=724.345, the tetragonal system, P4/mmm, a =3.84872(6) Å, c = 12.0771(3) Å, V=178.89 Å3, Z=1, Dx=6.7235 g cm−3, μ=1146.939 cm−1 (λ= 1.54051 Å), F(000) = 315.4, the structure was refined with 26 parameters to Rwp=6.70%, Rp=5.11% for 2926 step intensities and Rb=7.83%, Rf=6.70% for 131 peaks, “goodness of fit” S = 1.75.

Towards a more reliable symmetry determination from powder diffraction: a redetermination of the low-temperature structure of 4-methylpyridine-N-oxide

2009 ◽  
Vol 65 (6) ◽  
pp. 784-786 ◽  
Author(s):  
Lukáš Palatinus ◽  
Françoise Damay
Keyword(s):  
Low Temperature ◽  
Powder Diffraction ◽  
Tunneling Spectroscopy ◽  
Temperature Structure ◽  
Determination Method ◽  
Neutron Data ◽  
Acta Cryst ◽  
Space Group ◽  
X Ray ◽  
New Space

The low-temperature structure of 4-methylpyridine-N-oxide was previously determined in symmetry P41 [Damay et al. (2006), Acta Cryst. B62, 627–633]. Using a recently published symmetry-determination method it was found that the true symmetry of the structure is P41212. The structure was refined in the new space group using X-ray and neutron data. The previously published structure is close to the newly refined structure, but the new structure is in agreement with the results of rotational tunneling spectroscopy, and, in contrast to the structure in symmetry P41, does not require a twofold degeneracy of the tunneling bands.

Sign in / Sign up

Export Citation Format

Share Document