Disordered crystal structure of pentamethylcyclopentadienylsodium as seen by high-resolution X-ray powder diffraction

2001 ◽  
Vol 57 (5) ◽  
pp. 673-679 ◽  
Author(s):  
Consiglia Tedesco ◽  
Robert E. Dinnebier ◽  
Falk Olbrich ◽  
Sander van Smaalen

The crystal structure of pentamethylcyclopentadienylsodium, [NaC10H15] (NaCp*), has been determined from high-resolution X-ray powder diffraction. The compound crystallizes in space group Cmcm with lattice parameters a = 4.61030 (3), b = 16.4621 (3), c = 14.6751 (2) Å, V = 1113.77 (4) Å3 (Z = 4). NaCp* forms polymeric multidecker chains along the a axis. The Rietveld refinement (Rp = 0.050 and RF = 0.163) shows that the Cp* moieties occupy, with disorder, two different orientations rotated away from the eclipsed conformation by ±13.8°.

2008 ◽  
Vol 23 (3) ◽  
pp. 241-245
Author(s):  
L. Khemakhem ◽  
A. Kabadou ◽  
A. Ben Salah ◽  
N. Abdelmoula

Polycrystalline BaTi1−x(Zn1/3Nb2/3)xO3 (x=0.025 and 0.9) compounds were synthesized successfully and studied by XRD and dielectric measurements. The effects of the Ti/(Zn,Nb) ratio on the structure and dielectric properties of the compounds were investigated. XRD results indicated that the crystal structure of the x=0.09 compound is cubic perovskite with space group Pm3m and a=4.0095(4) Å. For the x=0.09 compound, a splitting of the (200) peak was observed near 40.2°, indicating that the crystal structure changed from cubic to tetragonal, with space group P4mm, a=4.026(4) Å, and c=4.0091(4) Å. Rietveld refinement of the crystal structures led to final confidence factors Rp=0.0353 and Rp=0.0349 for x=0.025 and 0.9, respectively. Dielectric measurements showed a relaxor behavior present in BaTi0.1(Zn1/3Nb2/3)0.9.


2007 ◽  
Vol 353-358 ◽  
pp. 3043-3046 ◽  
Author(s):  
Ping Li Qin ◽  
Liang Qin Nong ◽  
Ji Liang Zhang ◽  
Hai Qing Qin ◽  
Jiang Ping Liao ◽  
...  

The crystal structure of a new compound NdFeSb3 has been determined by X-ray powder diffraction using the Rietveld method. The compound crystallizes in the orthorhombic, space group Pbcm (No.57) with the CeNiSb3 structure type and lattice parameters a=1.26828(2)nm, b=0.61666(2)nm, c=1.81867(4) nm, z=12 and Dcalc=7.917g/cm3.


2002 ◽  
Vol 17 (2) ◽  
pp. 132-134
Author(s):  
Y. C. Lan ◽  
X. L. Chen ◽  
Z. Tao ◽  
A. Y. Xie ◽  
P. Z. Jiang ◽  
...  

The structure of a new iodate, (LiFe1/3)(IO3)2, has been determined. The new compound has a hexagonal structure with the lattice parameters a=5.4632(2) Å, c=5.0895(6) Å, Z=1. The density is 4.70 g cm−3. Rietveld refinement confirms that the compound has a space group of P63 (173). Fe and Li atoms randomly distribute on the 2a cation site.


2003 ◽  
Vol 18 (2) ◽  
pp. 140-143 ◽  
Author(s):  
Lingmin Zeng ◽  
Liangwei Chen ◽  
Shaoping Pu ◽  
Yikun Yang ◽  
Wenggui Gao ◽  
...  

X-ray powder diffraction data for the anticancer drug PtCl2(C2H3O2)2(C6H13N)(NH3) are reported. The crystal structure of PtCl2(C2H3O2)2(C6H13N)(NH3) obtained from a Rietveld refinement are: space group P21/a, a=13.547(2) Å, b=8.260(1) Å, c=14.638(3) Å, β=110.429(2)°, V=1534.96 Å3, Z=4 and Dcalc.=2.068 Mg/m3.


1997 ◽  
Vol 12 (2) ◽  
pp. 103-105 ◽  
Author(s):  
Shunkichi Ueno ◽  
Naoki Kamegashira

A Rietveld refinement of X-ray powder diffraction data for orthorhombic BaNd2Mn2O7 is reported. The refined lattice parameters were a=0.5517(5), b=0.5482(3), and c=2.0585(7) nm with space group Fmmm (No. 69).


2014 ◽  
Vol 950 ◽  
pp. 53-56
Author(s):  
Bin He ◽  
Ming Qin ◽  
Liu Qing Liang ◽  
Zhao Lu ◽  
De Gui Li ◽  
...  

Crystal structure and X-ray powder diffraction data for the Al7Cu5Y ternary compound are presented. The compound crystallizes in the body-centered tetragonal with the Al7Fe5Y structure type (space group I4/mmm), the lattice parameters a = 8.6960(9) Å, c = 5.1256(7) Å, V =387.62 Å3, Z =2, ڑx =5.102 g/cm3, F30 = 275.5(0.0033, 33) and RIR =1.23.


1999 ◽  
Vol 14 (4) ◽  
pp. 284-288 ◽  
Author(s):  
Hoong-Kun Fun ◽  
Ping Yang ◽  
Minoru Sasaki ◽  
Masasi Inoue ◽  
Hideoki Kadomatsu

The crystal structure of γ-Mo4O11 was obtained at room temperature (296 K) by Rietveld analysis with X-ray powder diffraction data. The crystal belongs to orthorhombic system, space group: Pna21, Z=4, Mr=559.753 (Atomic weights 1977), Dx=4.1228 g/cm3, F(000)=1024.0, μ=451.293 cm−1 (Int. Tab. Vol. C, Table 4.2.4.2, p. 193, λ=1.540 60 Å), a=24.4756(5) Å, b=6.7516(1) Å, c=5.4572(1) Å, and V=901.80(3) Å3. The structure was refined to Rwp=5.60%, Rp=4.27%, Rb=3.36%, and Rf=2.74% for 65 parameters with 3541 step intensities and 3055 peaks. Goodness of the fit S=3.35.


1994 ◽  
Vol 9 (3) ◽  
pp. 158-160 ◽  
Author(s):  
Zhengmin Fu ◽  
Wenxiu Li

The crystal structure of a new compound Li2Mg2(WO4)3 has been determined by means of X-ray powder diffraction. Li2Mg2(WO4)3 belongs to the orthorhombic system, with space group Pnma and the lattice parameters are: a = 5.1129 Å, b = 10.462 A, and c = 17.612 Å at room.temperature. Its measured density is Dm = 5.48 g/cm3, and each unit cell contains four formula weights.


2006 ◽  
Vol 21 (3) ◽  
pp. 220-224
Author(s):  
Koichiro Fukuda ◽  
Hajime Hasegawa ◽  
Tomoyuki Iwata ◽  
Shinobu Hashimoto

Crystal structure of Ca1.1Co1.9(PO4)2 was successfully determined from laboratory X-ray powder diffraction data (Co Kα) using direct methods and the Rietveld refinement. The crystal structure was found to be monoclinic (space group P21∕n, Z=4) with lattice dimensions of a=1.452 67(5) nm, b=0.494 34(1) nm, c=0.867 50(3) nm, β=92.316(1)°, and V=0.622 45(3) nm3. The final reliability indices calculated from the Rietveld refinement were Rwp=3.93%, Rp=3.02%, RB=4.10%, and S=1.48. Both Co and Ca atoms were distributed over the 2a and 2d sites with a preference of Ca at the 2d site. The coexistence of Co and Ca on the 2a and 2d sites is indispensable for stabilizing Ca1.1Co1.9(PO4)2 in the Ca3(PO4)2-Co3(PO4)2 system.


1993 ◽  
Vol 8 (3) ◽  
pp. 173-174 ◽  
Author(s):  
M. Venkateshwarlu ◽  
K. A. Hussain ◽  
T. Bhaskar Rao

The lattice parameters of triammonium citrate, (NH4)3C6H5O7, were determined by X-ray single crystal and powder diffraction methods. The crystal structure is orthorhombic with a = 6.187 ± 0.001 Å, b = 14.803 ± 0.004 Å, and c = 10.826 ± 0.003 Å, and from the systematic absences, the space group is Pcc2 ().


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