scholarly journals Structure Determination of New Phases K1.65V1.78W0.22O2(AsO4)2and K2V2O2(AsO4)2

2014 ◽  
Vol 70 (a1) ◽  
pp. C236-C236
Author(s):  
Djillali Mezaoui ◽  
Sabrina Belkhiri ◽  
Thierry Belkhiri

Two new phases K1.65V1.78W0.22O2(AsO4)2 and K2V2O2(AsO4)2 [1,2] belonging to KTiOPO4 family (KTP) [3] have been synthesized and characterized by single crystal X-ray diffraction. The structure of K1.65V1.78W0.22O2(AsO4)2 shows an irregular MO6 octahedra (M=78%V+22%W) with two abnormal short bonds M–O (1.774 (7) Å) and (1.824 (8) Å) which suggest that the non linear optical property could be more important. In order to show the influence of the tungsten and vanadium on the distortion of the MO6 octahedra, we substituted the tungsten by the vanadium element. The single-crystal K2V2O2(AsO4)2 consists of common VO6 octahedra with one short bond V–O (1.652(2) Å) . We used SUPERFLIP and JANA 2006 programs [4, 5] to resolve and refine these structures. The refinement by JANA 2006 led to the reliability factors: (R =0.048, Rw = 0.064) for K1.65V1.78W0.22O2(AsO4)2, and (R =0.028, Rw = 0.034) for K2V2O2(AsO4). Structure of K1.65V1.78W0.22O2(AsO4)2 Structure of K2V2O2(AsO4)2 Space group: Pc21n Space group: Pc21n Cell parameters: Cell parameters: a = 6.5322 (7) Å a = 6.5368 (2) Å b = 10.7228 (9) Å b = 10.7228 (5) Å c = 13.0782 (5) Å c = 13.0666 (4) Å

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.


1980 ◽  
Vol 35 (8) ◽  
pp. 1015-1018 ◽  
Author(s):  
Werner Winter ◽  
Hanspeter Bühl ◽  
Herbert Meier

Abstract Fragmentation of 1,2,3-thiadiazoles (1) leads to the compounds 5 - 8 with an increasing proportion of sulphur. Numerous structural possibilities exist for the products 7 with the general formula (R2C2)2S3. The number of proposals can be reduced by spectroscopic techniques, but the final structure determination is accomplished by an X-ray analysis of the title compound 7a. 7a crystallizes in the space group P21/c (Z = 4) with cell parameters of a = 9.714(1), b = 16.188(8), c = 9.149(2) Å and β = 98.93(1)°. The structure is solved by direct methods and refined to R = 0.053 with 1955 diffractometer data (I ≥ 2σ(I)). The trithiolane ring has a puckered conformation and the whole molecule shows nearly perfect C2-symmetry, which is not required crystallographically.


Author(s):  
A. E. Gunnæs ◽  
A. Olsen ◽  
P. T. Zagierski ◽  
B. Klewe ◽  
O. B. Karlsen ◽  
...  

AbstractThe crystal structure of


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Akhmatkhodja N. Yunuskhodjayev ◽  
Shokhista F. Iskandarova ◽  
Vahobjon Kh. Sabirov

Abstract The crystal structure of a copper(II) complex of protonated sildenafil, CuCl3C22H31N6O4S⋅2H2O was studied by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P21/n with the unit cell parameters a = 15.4292(2), b = 9.06735(12), c = 21.1752(2) Å, V = 2945.48(7) Å3, Z = 4. The Cu atom is coordinated by the sildenafil ligand via the N2 atom of the pyrazolopyrimidine ring and by three chloride anions. Sildenafil is protonated at the methylated N6 atom of the piperazine ring and it is cation ligand with a 1+ charge.


1988 ◽  
Vol 66 (7) ◽  
pp. 1770-1775 ◽  
Author(s):  
David J. Elliot ◽  
Sanna Haukilahti ◽  
David G. Holah ◽  
Alan N. Hughes ◽  
Stanislaw Maciaszek ◽  
...  

Reactions between Co(II), Diphos, and NaBH3CN lead to Co(BH3CN)2(Diphos)2, 1, or [Co(BH3CN)(Diphos)2]X, 2 (X = ClO4 or BPh4), and, in certain solvents, 2 reacts to produce [Co(CN)(Diphos)2](ClO4). Compound 1 can be reversibly converted to Co(BH3CN)2(DMF)4, 4, via Co(BH3CN)2(Diphos)(DMF). In addition, 1 reacts with CO to form the Co(I) and Co(III) compounds [Co(Diphos)2](CO)]X and [Co(Diphos)2(CN)2]X (X = BH3CN or BPh4). Single crystal X-ray diffraction studies of 4 show that the compound crystallizes in the triclinic space group [Formula: see text], with unit cell parameters a = 7.572(6), b = 9.695(6), c = 9.395(6) Å, α = 81.06(4), β = 68.46(5), γ = 68.19(5)°, V = 595.5 Å3, Z = 1, and dcalcd = 1.202 g cm−3. The structure converged to a conventional R factor of 0.040 for 2841 observations and showed an octahedral arrangement of four O atoms from DMF molecules and two trans N-bound BH3CN groups around the Co(II) center.


2002 ◽  
Vol 17 (1) ◽  
pp. 44-47
Author(s):  
Yu PuLan ◽  
Ding Shuang ◽  
Qiao YuanYuan ◽  
Yao XinKan ◽  
Liu Chong ◽  
...  

Two compounds have been studied by means of powder diffraction and their unit cell parameters are reported. The monoclinic cell parameters for dimethylgermanyl-bridged bis cyclopentadienyl tetracarbonyl diruthenium are a=11.03(2) Å, b=13.65(2) Å, c=11.609(2) Å, β=105.81(1)°, Z=4, space group P21/n (No. 14), Dx=2.135 mg/m3. The monoclinic cell parameters for λ-dimethylsilyl-dicyclopentadienyl-π, π′-tetracarbonyl diruthenium, are a=11.113(3) Å, b=13.60(1) Å, c=11.674(7) Å, and β=106.00(3)°, Z=4, space group P21/n (No. 14), and Dx=1.946 mg/m3. The cells found for the two compounds are in good agreement with those obtained from single crystal X-ray diffractometry.


1989 ◽  
Vol 42 (10) ◽  
pp. 1695 ◽  
Author(s):  
JC Coll ◽  
BW Skelton ◽  
AH White ◽  
AD Wright

Laurencia tenera has been shown to contain two novel sesquiterpenes. The structure of the less abundant metabolite (3) was determined by single-crystal X-ray diffraction as (1S,2R,4S,5R,6R,8S,9R)-4,8-dibromo-2,5,6,9-tetramethyltricyclo[7.2.0.01.6] undecane-3-one.‡ The more abundant, but less stable metabolite (4) was investigated by extensive high-field N.M.R. spectroscopy. Its structure is proposed as (1S*,2R*,4R*,5R*,6R*,8R*)-4-bromo-2,5,6-trimethyl-11-methylenetricyclo[6.2.1.01.6]undecan-3-one.§ The sesquiterpene (3) is isomeric with the known metabolite perforatone (5).


2003 ◽  
Vol 805 ◽  
Author(s):  
Hiroyuki Takakura ◽  
Akiji Yamamoto ◽  
Marc de Boissieu ◽  
Taku J Sato ◽  
An Pang Tsai

ABSTRACTA standard approach for structure solution of ordinary crystals begins with solving the phase problem. We show that a similar procedure can be taken even in the case of quasicrystals using single crystal X-ray diffraction by applying an ab initio structure determination method called the low density elimination method. The first picture of the occupation domains, which must be specified in a higher-dimensional structure determination of quasicrystals, is obtained from a phase-reconstructed density. We present six-dimensional densities determined by this method and give their interpretation for several different types of icosahedral quasicrystals.


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