Oxide meets silicide – synthesis and single-crystal structure of Ca21SrSi24O2

2017 ◽  
Vol 72 (4) ◽  
pp. 313-316
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo

AbstractA few black, rectangular thin plates of Ca21SrSi24O2 were obtained by serendipity in a solid-state reaction of calcium metal, strontium chloride and silicon powder at 1200 K for 2 days designed to produce ‘Ca2SrCl2[Si3]’. The title compound forms next to some CaSi and some remaining educts. Ca21SrSi24O2 crystallizes in the monoclinic space group C2/m (no. 12) with unit cell parameters of a=1895.2(2), b=450.63(5) and c=1397.33(18) pm and β=112.008(7)° (Z=1). The title compound shows planar, eight-membered, kinked Si8 chains with Si–Si distances between 241.4 and 245.0 pm indicating bonding interactions and kinked ‘rope ladders’ connecting the chains with interatomic Si–Si distances in the range 268.1–274.7 pm. Embedded in between these silicon substructures are columns of oxygen centered, apex sharing [(Ca1−x Srx)6/2O] octahedra and calcium ions.

1988 ◽  
Vol 41 (9) ◽  
pp. 1363 ◽  
Author(s):  
A Abouhamdan ◽  
SF Lincoln ◽  
MR Snow ◽  
ERT Tiekink

The crystal structure of the title compound [K(-NHCH2CH2OCH2CH2OCH2CH2NHCH2CH2OCH2CH2-)(NCS)] has been determined. Potassium(I) is 1.41 Ǻ above the plane of the three oxygens of the 4,7,13-trioxa-1,10-diazacyclopentadecane ligand, and is seven-coordinated. Potassium(I) is 2.871(7), 2.798(7) and 2.772(7)Ǻ from the three oxygens, and 2.905(8) and 2.945(8)Ǻ from the two nitrogens of 4,7,13-trioxa-1,10-diazacyclopentadecane, 2.861(7)Ǻ from an oxygen of a second such ligand, and 2.809(8)Ǻ from the thiocyanate nitrogen. Crystals are monoclinic, space group P21/n with unit cell parameters a 8.015(4), b 14.755(4), c 13.744(4)Ǻ, β 95.37(3)°, and Z 4. The structure was solved by direct methods and refined by a full-matrix least-squares procedure to final R 0.089, Rw 0.099 for 981 reflections with I ≥ 2.5σ(I).


2017 ◽  
Vol 72 (2) ◽  
pp. 95-99 ◽  
Author(s):  
Yang Chi ◽  
Yan Zhuang ◽  
Sheng-Ping Guo

AbstractThe synthesis and crystal structure of the rare earth borogermanate EuGeBO5 are reported. It is synthesized by high-temperature solid-state reaction and crystallizes in the monoclinic space group P21/c (no. 14) with the unit cell parameters a=4.8860(5), b=7.5229(8), c=9.9587(10) Å, and β=91.709(3)°. Its crystal structure features a polyanion-type layer (GeBO5)3− constructed by BO4 and GeO4 tetrahedra connected alternatingly. Eu3+ ions are located in cavities and are coordinated by eight O atoms. Various structures of the related compounds REMM′O5 (RE=rare earth metal; M=Si, Ge, and Sn; M′=B, Al, and Ga) are also discussed.


2000 ◽  
Vol 55 (3-4) ◽  
pp. 238-242 ◽  
Author(s):  
A. B. M. Shamsur Rahman ◽  
H. Boiler ◽  
K. O. Klepp

Abstract Red-brown crystals of a new bis(thiomolybdate) complex [Me4N]3[(MoOS3)2Ag] were formed at room temperature through the reaction of a solution of [Me4N]2[MoOS3] in MeCN with solid AgCN. They are monoclinic, space group P21/c with unit cell parameters a = 16.662(9), b = 9.464(3), c = 17.890(8) A, /3 = 101.87(2)°, Z = 4. The crystal structure was determined from single crystal diffractometer data (MoKα-radiation) and refined to R = 0.044 (3614 reflections, 236 variable parameters). The structure is characterized by trinuclear complex anions, [(MoOS3)2Ag]3-. According to Weissenberg investigations the homologous tungsten compound is isostructural. The infrared spectrum of the molybdenum complex (KBr powder) shows absorption bands at 884 (vs) and 871 (w) cm-1 (terminal v(Mo-0)), 483 (vs) cm-1 (terminal v(Mo-S)), 451 (vs), and 435 (w) cm-1 (bridging v(Mo-S)). The tungsten complex showed bands at 901 (vs) cm-1 (terminal v(W-O)), 478 (vs) cm-1 (terminal v(W-S)), and 435 (vs) cm-1 (bridging v(W-S)). The anionic mass spectra shows molecular ion peaks at m/z 524 and 700 for [(MoOS3)2Ag]- and [(WOS3)2Ag]-, respectively, as well as peaks for other fragments.


2008 ◽  
Vol 23 (3) ◽  
pp. 232-240
Author(s):  
Abderrahim Aatiq ◽  
Rachid Bakri ◽  
Aaron Richard Sakulich

Synthesis and structure of two phosphates belonging to the ternary Sb2O5–In2O3–P2O5 system are realized. Structures of SbV1.50InIII0.50(PO4)3 and (SbV0.50InIII0.50)P2O7 phases, obtained by solid state reaction in air at 950 °C, were determined at room temperature from X-ray powder diffraction using the Rietveld method. SbV1.50InIII0.50(PO4)3 have a monoclinic (space group P21/n) distortion of the Sc2(W O4)3-type framework. Its structure is constituted by corner-shared SbO6 or InO6 octahedra and PO4 tetrahedra. Monoclinic unit cell parameters are a=11.801(2) Å, b=8.623(1) Å, c=8.372(1) Å, and β=90.93(1)°. (Sb0.50In0.50)P2O7 is isotypic with (Sb0.50Fe0.50)P2O7 and crystallizes in orthorhombic system (space group Pna21) with a=7.9389(1) Å, b=16.0664(2) Å, and c=7.9777(1) Å. Its structure is built up from corner-shared SbO6 or InO6 octahedra and P2O7 groups (two group-types). Each P2O7 group shares its six vertices with three SbO6 and three InO6 octahedra, and each octahedron is connected to six P2O7 groups.


Author(s):  
Analio Dugarte-Dugarte ◽  
Nahum Ramírez Pineda ◽  
Luis Nieves ◽  
José Antonio Henao ◽  
Graciela Díaz de Delgado ◽  
...  

Almost 50 years after the initial report, the crystal structure of Cu2GeSe3, a I2-IV-VI3 semiconductor, has been revised using modern single-crystal X-ray diffraction data. The structure of this material can be properly described in the monoclinic space group Cc (No. 9) with unit-cell parameters a = 6.7703 (4) Å, b = 11.8624 (5) Å, c = 6.7705 (4) Å, β = 108.512 (6)°, V = 515.62 (5) Å3, Z = 4, rather than in the orthorhombic space group Imm2 (No. 44) with unit-cell parameters a = 11.860 (3), b = 3.960 (1), c = 5.485 (2) Å, V = 257.61 Å3, Z = 2, as originally proposed [Parthé & Garín (1971). Monatsh. Chem. 102, 1197–1208]. Contrary to what was observed in the orthorhombic structure, the distortions of the tetrahedra in the monoclinic structure are consistent with the distortions expected from considerations derived from the bond valence model. A brief revision of the structures reported for the I2-IV-VI3 family of semiconducting compounds (I: Cu, Ag; IV: Si, Ge, Sn; and VI: S, Se, Te) is also presented.


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.


2013 ◽  
Vol 9 (2) ◽  
pp. 1975-1987
Author(s):  
Ben Tahar Fayçal ◽  
Perez Olivier ◽  
Slaheddine Chaabouni

An hepta (pyridinium) bis (hexachlorobismuthate (III)) nitrate, (C5H6N)7(BiCl6)2(NO3) crystallizes at room temperature in the monoclinic system, space group P21/n, with the following unit-cell parameters: a = 9.555(1) Å, b = 16.847(1) Å, c = 32.522(1) Å, β = 94.37° , V = 5219.8 Å3 and four molecules per unit cell. Its crystal structure was determined and refined down to R1 = 0.0504, wR2 = 0.0667. The structure of the title compound, (C5H6N)7(BiCl6)2(NO3) consists of seven monoprotonated pyridinium (C5H6N)+ cations, two independent octahedron [BiCl6]3- and an isolated NO3- anion. These entities are linked together through N-H.....Cl and N-H.....O hydrogen bonds, originating from the (C5H6N)+ groups and the isolated anion of nitrate to forming a three dimensional network.


2014 ◽  
Vol 70 (10) ◽  
pp. 1402-1405 ◽  
Author(s):  
Hua Wang ◽  
Huaidong Zhang ◽  
Yanling Mi ◽  
Jianhua Ju ◽  
Qi Chen ◽  
...  

β-Carboline alkaloids (βCs), with tricyclic pyrido[3,4-b]indole rings, have important pharmacological and therapeutic value. In the biosynthesis of βCs, the Pictet–Spengler (PS) cyclization reaction is responsible for the formation of ring structures. McbB is one of a few enzymes that are known to catalyse PS cyclization. It can also catalyse decarboxylation and oxidation. Here, the expression, crystallization and preliminary data analysis of McbB are reported. The crystals diffracted to 2.10 Å resolution and belonged to the monoclinic space groupP21, with unit-cell parametersa= 66.06,b= 85.48,c= 106.19 Å, α = 90.00, β = 106.77, γ = 90.00°. These results provide a basis for solving the crystal structure and elucidating the catalytic mechanism for McbB.


1988 ◽  
Vol 41 (3) ◽  
pp. 405 ◽  
Author(s):  
BF Hoskins ◽  
ERT Tiekink

The crystal structure of the title compound, (c-C6H11)2P(S)C(S)SMe , has been determined and shows that the P(S)C(S)SC chromophore is situated on a crystallographic mirror plane with the cyclohexyl groups related to each other across this plane. Significant interatomic distances are: P=S 1.951(1), P-C 1.860(4), C=S 1.632(4) and C-S 1.700(4)Ǻ. A resonance scheme involving the delocalization of π-electrons over the CS2 moiety has been invoked to account for the observed C-S bond distances in the molecule. Crystals are orthorhombic, space group Pnma with unit cell parameters a 10.196(2), b 10.612(1) and c 15.370(3)Ǻ, and Z 4. The structure was solved by direct methods and refined by a full-matrix least-squares procedure to final R 0.045, Rw 0.047 for 1191 reflections with I ≥ 3.0σ(I).


2013 ◽  
Vol 6 (1) ◽  
pp. 129-132 ◽  
Author(s):  
Darina Lacková ◽  
Iveta Ondrejkovičová ◽  
Marián Koman

Abstract The title compound, (NH4)2[FeCl5H2O] has been prepared by reaction between iron(III) chloride and ammonium chloride which was formed by hydrolysis of isonicotinamide or thionicotinamide in ethanol. The characterization was based on elemental analysis and infrared spectra. The crystal structure of the title compound has been refined by single crystal X-ray diffraction method at 293 K. Crystals are orthorhombic, Pnma, with unit cell parameters: a = 13.760(1) A, b = 9.960(1) A, c = 7.060(1) A, Z = 4 and R = 3.5 %. The iron(III) atom in [FeCl5(H2O)]2- ion is approximately octahedrally coordinated by five Cl atoms and one O atom of H2O molecule. This distortion is caused by the extensively hydrogen-bonded lattice. Structural parameters and IR spectra of similar compounds are compared and discussed.


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