Selenium (Se) crystal structure, lattice and cell parameters, monoclinic selenium (alpha, beta, gamma)

Author(s):  
2012 ◽  
Vol 9 (2) ◽  
pp. 87
Author(s):  
Mohd Abdul Fatah Abdul Manan ◽  
M. Ibrahim M. Tahir ◽  
Karen A. Crouse ◽  
Fiona N.-F. How ◽  
David J. Watkin

The crystal structure of the title compound has been determined. The compound crystallized in the triclinic space group P -1, Z = 2, V = 1839 .42( 18) A3 and unit cell parameters a= 11. 0460( 6) A, b = 13 .3180(7) A, c=13. 7321 (8) A, a = 80.659(3 )0, b = 69 .800(3 )0 and g = 77 .007 (2)0 with one disordered dimethylsulfoxide solvent molecule with the sulfur and oxygen atoms are distributed over two sites; S101/S102 [site occupancy factors: 0.6035/0.3965] and 0130/0131 [site occupancy factor 0.3965/0.6035]. The C22-S2 l and C 19-S20 bond distances of 1. 779(7) A and 1. 788(8) A indicate that both of the molecules are connected by the disulfide bond [S20-S21 2.055(2) A] in its thiol form. The crystal structure reveals that both of the 5-bromoisatin moieties are trans with respect to the [S21-S20 and CI 9-Nl 8] and [S20-S21 and C22-N23] bonds whereas the benzyl group from the dithiocarbazate are in the cis configuration with respect to [S21-S20 and C19-S44] and [S20-S21 and C22-S36] bonds. The crystal structure is further stabilized by intermolecular hydrogen bonds of N9-H35···O16 formed between the two molecules and N28-H281 ···O130, N28-H281 ···O131 and C4 l-H4 l l ···O 131 with the solvent molecule.


2021 ◽  
pp. 1-6
Author(s):  
Mariana M. V. M. Souza ◽  
Alex Maza ◽  
Pablo V. Tuza

In the present work, LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites were synthesized by the modified Pechini method. These materials were characterized using X-ray fluorescence, scanning electron microscopy, and powder X-ray diffraction coupled to the Rietveld method. The crystal structure of these materials is orthorhombic, with space group Pbnm (No 62). The unit-cell parameters are a = 5.535(5) Å, b = 5.527(3) Å, c = 7.819(7) Å, V = 239.2(3) Å3, for the LaNi0.5Ti0.45Co0.05O3, a = 5.538(6) Å, b = 5.528(4) Å, c = 7.825(10) Å, V = 239.5(4) Å3, for the LaNi0.45Co0.05Ti0.5O3, and a = 5.540(2) Å, b = 5.5334(15) Å, c = 7.834(3) Å, V = 240.2(1) Å3, for the LaNi0.5Ti0.5O3.


2015 ◽  
Vol 70 (3) ◽  
pp. 191-196 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo

AbstractThe new compounds LiK[C(CN)3]2 and Li[C(CN)3]·½ (H3C)2CO were synthesized and their crystal structures were determined. Li[C(CN)3]·½ (H3C)2CO crystallizes in the orthorhombic space group Ima2 (no. 46) with the cell parameters a=794.97(14), b=1165.1(2) and c=1485.4(3) pm, while LiK[C(CN)3]2 adopts the monoclinic space group P21/c (no. 14) with the cell parameters a=1265.7(2), b=1068.0(2) and c=778.36(12) pm and the angle β=95.775(7)°. Single crystals of K[C(CN)3] were also acquired, and the crystal structure was refined more precisely than before corroborating earlier results.


Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1028 ◽  
Author(s):  
M. Mashrur Zaman ◽  
Sytle M. Antao

This study investigates the crystal chemistry of monazite (APO4, where A = Lanthanides = Ln, as well as Y, Th, U, Ca, and Pb) based on four samples from different localities using single-crystal X-ray diffraction and electron-probe microanalysis. The crystal structure of all four samples are well refined, as indicated by their refinement statistics. Relatively large unit-cell parameters (a = 6.7640(5), b = 6.9850(4), c = 6.4500(3) Å, β = 103.584(2)°, and V = 296.22(3) Å3) are obtained for a detrital monazite-Ce from Cox’s Bazar, Bangladesh. Sm-rich monazite from Gunnison County, Colorado, USA, has smaller unit-cell parameters (a = 6.7010(4), b = 6.9080(4), c = 6.4300(4) Å, β = 103.817(3)°, and V = 289.04(3) Å3). The a, b, and c unit-cell parameters vary linearly with the unit-cell volume, V. The change in the a parameter is large (0.2 Å) and is related to the type of cations occupying the A site. The average <A-O> distances vary linearly with V, whereas the average <P-O> distances are nearly constant because the PO4 group is a rigid tetrahedron.


2017 ◽  
Vol 81 (4) ◽  
pp. 917-922
Author(s):  
Peter Elliott

AbstractThe crystal structure of the copper aluminium phosphate mineral sieleckiite, Cu3Al4(PO4)2 (OH)12·2H2O, from the Mt Oxide copper mine, Queensland, Australia was solved from single-crystal X-ray diffraction data utilizing synchrotron radiation. Sieleckiite has monoclinic rather than triclinic symmetry as previously reported and is space group C2/m with unit-cell parameters a = 11.711(2), b = 6.9233(14), c = 9.828(2) Å, β = 92.88(3)°, V = 795.8(3) Å3and Z = 2. The crystal structure, which has been refined to R1 = 0.0456 on the basis of 1186 unique reflections with Fo > 4σF, is a framework of corner-, edge- and face- sharing Cu and Al octahedra and PO4 tetrahedra.


2012 ◽  
Vol 76 (3) ◽  
pp. 443-453 ◽  
Author(s):  
J. Plášil ◽  
K. Fejfarová ◽  
R. Skála ◽  
R. Škoda ◽  
N. Meisser ◽  
...  

AbstractTwo crystals of the uranyl carbonate mineral grimselite, ideally K3Na[(UO2)(CO3)3](H2O), from Jáchymov in the Czech Republic were studied by single-crystal X-ray diffraction and electron-probe microanalysis. One crystal has considerably more Na than the ideal chemical composition due to substitution of Na into KO8 polyhedra; the composition of the other crystal is nearer to ideal, and similar to synthetic grimselite. The presence of Na atoms in KO8 polyhedra, which are located in channels in the crystal structure, reduces their volume, and as a result the unit-cell volume also decreases. Structure refinement shows that the formula for the sample with the anomalously high Na content is (K2.43Na0.57)Σ3.00Na[(UO2)(CO3)3](H2O). The unit-cell parameters, refined in space group P2c, are a = 9.2507(1), c = 8.1788(1) Å, V = 606.14(3) Å3 and Z = 2. The crystal structure was refined to R1 = 0.0082 and wR1 = 0.0185 with a GOF = 1.33, based on 626 observed diffraction peaks [Iobs>3σ(I)].


Author(s):  
Yaoguang Chen ◽  
Xiaocheng Huang ◽  
Rongzhi Wang ◽  
Shihua Wang ◽  
Ning Shi

A fluorobody is a manmade hybrid molecule that is composed of green fluorescent protein (GFP) and a fragment of antibody, which combines the affinity and specificity of an antibody with the visibility of a GFP. It is able to provide a real-time indication of binding while avoiding the use of tags and secondary binding reagents. Here, the expression, purification and crystal structure of a recombinant fluorobody for TLH (thermolabile haemolysin), a toxin from the lethal food-borne disease bacteriumVibrio parahaemolyticus, are presented. This is the first structure of a fluorobody to be reported. Crystals belonging to space groupP43212, with unit-cell parametersa=b= 63.35,c = 125.90 Å, were obtained by vapour diffusion in hanging drops and the structure was refined to anRfreeof 16.7% at 1.5 Å resolution. The structure shows a CDR loop of the antibody on the GFP scaffold.


2013 ◽  
Vol 28 (1) ◽  
pp. 13-17 ◽  
Author(s):  
F. Laufek ◽  
A. Vymazalová ◽  
D.A. Chareev ◽  
A.V. Kristavchuk ◽  
J. Drahokoupil ◽  
...  

The (Ag,Pd)22Se6 phase was synthesized from individual elements by silica glass tube technique and structurally characterized from powder X-ray diffraction data. The (Ag,Pd)22Se6 phase crystallizes in Fm$\overline3$m symmetry, unit-cell parameters: a = 12.3169(2) Å, V = 1862.55(5) Å3, Z = 4, and Dc = 10.01 g/cm3. The crystal structure of the (Ag,Pd)22Se6 phase represents a stuffed 3a.3a.3a superstructure of the Pd structure (fcc), where only 4 from 108 available octahedral holes are occupied. Its crystal structure is related to the Cr23C6 structure type.


2005 ◽  
Vol 20 (3) ◽  
pp. 203-206 ◽  
Author(s):  
M. Grzywa ◽  
M. Różycka ◽  
W. Łasocha

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.


2015 ◽  
Vol 71 (9) ◽  
pp. 1189-1193 ◽  
Author(s):  
Yoshiki Aikawa ◽  
Hiroshi Kida ◽  
Yuichi Nishitani ◽  
Kunio Miki

Proper protein folding is an essential process for all organisms. Prefoldin (PFD) is a molecular chaperone that assists protein folding by delivering non-native proteins to group II chaperonin. A heterohexamer of eukaryotic PFD has been shown to specifically recognize and deliver non-native actin and tubulin to chaperonin-containing TCP-1 (CCT), but the mechanism of specific recognition is still unclear. To determine its crystal structure, recombinant human PFD was reconstituted, purified and crystallized. X-ray diffraction data were collected to 4.7 Å resolution. The crystals belonged to space groupP21212, with unit-cell parametersa= 123.2,b= 152.4,c= 105.9 Å.


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