New X-Ray Powder Data for Gorceixite, BaAl3(PO4)2(OH)5·H2O, an Evaluation of d-Spacings and Intensities, Pseudosymmetry and Its Influence on the Figure of Merit

1989 ◽  
Vol 4 (4) ◽  
pp. 227-230 ◽  
Author(s):  
Frank N. Blanchard

AbstractNew powder and crystallographic data for gorceixite, a mineral of the crandallite subgroup of the alunite group, are reported and compared with current Powder Data File (PDF) patterns and with calculated patterns. Both d-spacings and intensities have been evaluated, and the results indicate a significant improvement over existing patterns. Indexing of the reflections is given for the true monoclinic symmetry, Cm (8), the pseudorhombohedral symmetry, (166) (to compare with structurally analogous minerals), and the pseudocubic symmetry, Fm3m (225). Because of the strong pseudosymmetry, the overall figure of merit is lower than would be the case for indexing in one of the pseudospace groups.

1985 ◽  
Vol 18 (6) ◽  
pp. 541-541
Author(s):  
A. Sen Gupta ◽  
C. Aravindakshan

Indexing of the powder diffraction data and refinement of the unit-cell parameters for N,N'-bis(aminoacetyl)urea (NH2CH2CO)2(NH)2CO are reported. The refined crystallographic data are: C5H10N403, P21/n (probable) a = 5.5436 (6) Å, b = 12.0338 (8) Å, c = 5.1243 (4) Å, β = 111.696 (6)°, V = 317.63, Z = 2, Dm = 1.84, Dx = 1.82 g cm-3 Cu Kα. The quantitative figure of merit (FN ) is F 20 = 22(0.014556, 64). The JCPDS Diffraction File No. for C5H10N403 is 36-1999.


1984 ◽  
Vol 259 (20) ◽  
pp. 12714-12717
Author(s):  
M A Navia ◽  
J P Springer ◽  
M Poe ◽  
J Boger ◽  
K Hoogsteen

1985 ◽  
Vol 21 (1) ◽  
pp. 65-70 ◽  
Author(s):  
P. Corradini ◽  
R. Napolitano ◽  
V. Petraccone ◽  
B. Pirozzi ◽  
A. Tuzi

2006 ◽  
Vol 61 (6) ◽  
pp. 758-765 ◽  
Author(s):  
Matthias Nolte ◽  
Ingo Pantenburg ◽  
Gerd Meyer

[{Hg(CF3)2}(ThpH)(H2O)](H2O) (1), [{Hg4(Thp)4}(ClO4)4(H2O)8](H2O)4 (2), [{Hg(ThpH)2} (NO3)](NO3) (3) and {Hg(Thp)Cl}(H2O) (4) (ThpH = theophylline, C7H8N4O2) have been synthesized by slow evaporation of aqueous solutions of the mercuric salts Hg(CF3)2, Hg(ClO4)2, Hg(NO3)2, or HgCl2 and theophylline. Their crystal structures were determined on the basis of single crystal X-ray data. The coordination polymers 1 and 2 crystallize with triclinic symmetry, P1̅ (no. 2), with a = 468.8(2), b = 1256.4(5), c = 1445.5(6) pm, α = 67.15(3), β = 89.21(3), γ = 89.40(3)° and a = 833.6(1), b = 1862.7(2), c = 2182.9(2) pm, α = 111.61(1), β = 90.98(1), γ = 95.51(1)°, respectively. 3 and 4 crystallize with monoclinic symmetry, Pc (no. 7), a =1194.1(1), b=1258.8(2), c=735.5(2) pm, β =96.96(2)° and P21/n (no. 14), a=1069.0(2), b =911.6(1), c=1089.9(2) pm and β = 96.87(2)°. In 1 the theophylline molecules are non-coordinating to mercury and leave the Hg(CF3)2 molecule unchanged. Only weak electrostatic attractions to one keto-oxygen atom of theophylline and one water molecule hold this co-crystallisate together. In 2, the theophyllinate anion, Thp−, strongly coordinates with both N(7) and N(9) to HgII forming a large ring with eight Hg atoms that incorporates the water molecules. One sort of nitrate ions in 3 is weakly attached to HgII with the theophylline molecules still bound strongly through N(9). The chloride ligand and the theophyllinate ion seem to have the same strengths as ligands in 4 as they are both attached to HgII with the shortest distances possible


2010 ◽  
Vol 25 (3) ◽  
pp. 247-252 ◽  
Author(s):  
F. Laufek ◽  
J. Návrátil

The crystal structure of skutterudite-related phase IrGe1.5Se1.5 has been refined by the Rietveld method from laboratory X-ray powder diffraction data. Refined crystallographic data for IrGe1.5Se1.5 are a=12.0890(2) Å, c=14.8796(3) Å, V=1883.23(6) Å3, space group R3 (No. 148), Z=24, and Dc=8.87 g/cm3. Its crystal structure can be derived from the ideal skutterudite structure (CoAs3), where Se and Ge atoms are ordered in layers perpendicular to the [111] direction of the original skutterudite cell. Weak distortions of the anion and cation sublattices were also observed.


1999 ◽  
Vol 604 ◽  
Author(s):  
Rosa E. Meléndez ◽  
Andrew J. Carn ◽  
Kazuki Sada ◽  
Andrew D. Hamilton

AbstractThe use of organic molecules as gelators in certain organic solvents has been the target of recent research in materials science. The types of structures formed in the gel matrix have potential applications as porous solids that can be used as absorbents or in catalysis. We will present and discuss the organogelation properties of a family of bis-ureas. Studies presented will include a molecule structure activity relationship, thermodynamic properties, comparison to x-ray crystallographic data and potential functionalization of the gels formed by this class of compounds


Author(s):  
Robert E. Dinnebier ◽  
Hanne Nuss ◽  
Martin Jansen

AbstractThe crystal structures of solvent-free lithium, sodium, rubidium, and cesium squarates have been determined from high resolution synchrotron and X-ray laboratory powder patterns. Crystallographic data at room temperature of Li


1995 ◽  
Vol 10 (4) ◽  
pp. 290-292 ◽  
Author(s):  
Mikio Sakaguchi ◽  
Ichiro Sakamoto ◽  
Ryuichi Akagi ◽  
Hideo Toraya

X-ray powder diffraction data for a new potassium sodium silicate Na1.3K0.7Si2O5are reported. The sample was prepared by calcining a mixture of NaOH, KOH, and sodium silicate (SiO2/Na2O=3.54, moisture content=60%) at 873 K for 2 h. The crystallographic data obtained by using the whole-powder-pattern decomposition method are Na1.3K0.7Si2O5, monoclinic, P21/c, a=4.8426(1) Å,b= 8.6892(2) Å,c= 11.9686(3) Å,β=90.373(2)°,V=503.60(2) Å3,Z=4,Dx= 2.51 g/cm3.


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