Tetramethylammonium bifluoride, crystal structure and vibrational spectra

1989 ◽  
Vol 67 (11) ◽  
pp. 1898-1901 ◽  
Author(s):  
William W. Wilson ◽  
Karl O. Christe ◽  
Jin-an Feng ◽  
Robert Bau

Single crystals of [N(CH3)4]HF2 were obtained as a by-product during the recrystallization of [N(CH3)4]ClF4 from CH3CN solution. X-ray diffraction data show that [N(CH3)4]HF2 crystallizes in the orthorhombic space group Pmn21 with Z = 2 and unit cell dimensions a = 6.611(5), b = 8.753(5), and c = 5.386(4) Å. The structure was solved by direct methods and refined by least squares to a final R = 0.055 by using 205 independent reflections. The HF2− anions are symmetric, exhibit an unusually short [Formula: see text] distance of 2.213(4) Å, and vibrational frequencies close to those of the free HF2− anion. Keywords: tetramethylammonium bifluoride, crystal structure, Raman spectrum.

1987 ◽  
Vol 65 (12) ◽  
pp. 2830-2833 ◽  
Author(s):  
David M. McKinnon ◽  
Peter D. Clark ◽  
Robert O. Martin ◽  
Louis T. J. Delbaere ◽  
J. Wilson Quail

3,5-Diphenyl-1,2-dithiolium-4-olate (1) reacts with aniline to form 1-phenylimino-2-phenylamino-3-phenylindene (3a). Under suitable conditions, 6-phenylbenzo[b]indeno[1,2-e]-1,2-thiazine is also formed. These structures are confirmed by alternative syntheses. The molecular structure of 3a has been determined by single crystal X-ray diffraction. Compound 3a crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 20.777(3) Å, b = 6.130(3) Å, c = 31.327(3) Å, 3 = 99.59(1)°, and Z = 8. The structure was solved by direct methods and refined by least squares to a final R = 0.055. The molecular structure of 3a shows the three phenyl containing substituents to have the planes of their ring systems tilted between 40° and 60° from the plane of the indene system due to steric repulsions.


2005 ◽  
Vol 61 (6) ◽  
pp. 717-723 ◽  
Author(s):  
Patricia Lozano-Casal ◽  
David R. Allan ◽  
Simon Parsons

The crystal structure of cyclopropylamine at 1.2 GPa has been determined by X-ray diffraction methods. The structure of this phase is orthorhombic, space group Pbca and the unit-cell dimensions are a =  5.0741 (10), b  =  9.7594 (10) and c  =  13.305 (2) Å. Only one of the two H atoms of the amino group actively participates in the formation of the hydrogen-bonded chains, C(2) in graph-set notation, which lie parallel to the crystallographic a axis. Additionally, the topology of the crystal packing is studied using both Voronoi–Dirichlet polyhedra and Hirshfeld surface analyses for the low-temperature and the high-pressure structures of cyclopropylamine and the results are compared.


2020 ◽  
Vol 28 (2) ◽  
pp. 322-330
Author(s):  
Jakub Plášil

The crystal structure of the rare supergene Pb2+-containing uranyl-oxide mineral wölsendorfite has been revisited employing the single-crystal X-ray diffraction. The new structure refinement provided deeper insight into the complex structure of this mineral, revealing additional H2O sites in the interlayer complex and confirming the entrance of the Ca2+ into the structure. Studied wölsendorfite is orthorhombic, space group Cmcm, with unit cell dimensions a = 14.1233(8) Å, b = 13.8196(9) Å, c = 55.7953(12) Å, V = 10890.0(10) Å3, and Z = 8. The structure has been refined to an agreement index (R) of 10.74% for 3815 reflections with I > 3σ(I) collected using a microfocus X-ray source from the microcrystal. In line with the previous structure determination, the refined structure contains U–O–OH sheets of the wölsendorfite topology and an interstitial complex comprising nine symmetrically unique Pb sites, occupied dominantly by Pb2+. Nevertheless, one of the sites seems to be plausible for hosting Ca2+. Its presence has been successfully modeled by the refinement and further supported by the crystal-chemical considerations. The structural formula of wölsendorfite crystal studied is Pb6.07Ca0.68[(UO2)14O18(OH)5]O0.5(H2O)12.6, with Z = 8, Dcalc. = 6.919 g·cm–3 (including theoretical 30.2 H atoms). The rather complex structure of wölsendorfite makes it the third most complex known uranyl-oxide hydroxy-hydrate mineral.


1992 ◽  
Vol 7 (2) ◽  
pp. 109-111 ◽  
Author(s):  
C.J. Rawn ◽  
R.S. Roth ◽  
H.F. McMurdie

AbstractSingle crystals and powder samples of Ca2Bi5O5and Ca4Bi6O13have been synthesized and studied using single crystal X-ray diffraction as well as X-ray and neutron powder diffraction. Unit cell dimensions were calculated using a least squares analysis that refined to a δ2θof no more than 0.03°. A triclinic cell was found with space group , a = 10.1222(7), b = 10.1466(6), c = 10.4833(7) Å. α= 116.912(5), β= 107.135(6) and γ= 92.939(6)°, Z = 6 for the Ca2Bi2O5compound. An orthorhombic cell was found with space group C2mm, a = 17.3795(5), b = 5.9419(2) and c = 7.2306(2) Å, Z = 2 for the Ca4Bi6O13compound.


2011 ◽  
Vol 6 (11) ◽  
pp. 1934578X1100601
Author(s):  
Yang Li ◽  
Jun-Hui Zhou ◽  
Gui-Jun Han ◽  
Min-Juan Wang ◽  
Wen-Ji Sun ◽  
...  

The crystal structure of natural diterpenoid alkaloid ranaconitine isolated from Aconitum sinomontanum Nakai has been determined by single crystal X-ray diffraction analysis. The crystal presents a monoclinic system, space group C2 with Z = 4, unit cell dimensions a = 30.972(19) Å, b = 7.688(5) Å, and c = 19.632(12) Å. Moreover, the intermolecular O–H···O hydrogen bonds and weak π-π interactions play a critical role in expanding the dimensionality.


1994 ◽  
Vol 9 (1) ◽  
pp. 56-62 ◽  
Author(s):  
C. G. Lindsay ◽  
C. J. Rawn ◽  
R. S. Roth

Single crystals and powder samples of Ba4ZnTi11O27 and Ba2ZnTi5O13 have been synthesized and studied using single-crystal X-ray precession photographs and X-ray powder diffraction. Unit cell dimensions were calculated from a least-squares refinement with a final maximum Δ2θ of 0.05°. Both phases were found to have monoclinic cells, space group C2/m. The refined lattice parameters for the Ba4ZnTi11O27 compound are a= 19.8687(8) Å, b=11.4674(5) Å, c=9.9184(4) Å, β= 109.223(4)°, and Z=4. The refined lattice parameters for the Ba2ZnTi5O13 compound are a= 15.2822(7) Å, b=3.8977(1) Å, c=9.1398(3) Å, β=98.769(4)°, and Z=2.


1976 ◽  
Vol 29 (9) ◽  
pp. 1905 ◽  
Author(s):  
CL Raston ◽  
AH White ◽  
SB Wild

The crystal structure of the title compound has been determined by direct methods from X-ray diffraction data and refined by least squares to a residual of 0.071 for 2647 'observed' reflections. Crystals are monoclinic, C2/c, a = 36.81(1), b = 11.181(2), c = 20.369(5) �, β = 95.28(3)�, Z = 32. There are four independent molecules in the asymmetric unit, all with the cis disposition of ligands (<Fe-Hg), 2.498 �; <Hg-Fe-Hg), 80.9�); in one of the molecules one of the carbonyl sites is occupied by a more substantial moiety, possibly a result of partial occupancy of HgCl as a result of disorder or decomposition.


1981 ◽  
Vol 36 (2) ◽  
pp. 135-137 ◽  
Author(s):  
Evamarie Hey ◽  
Ulrich Müller

The crystal structure of [MePh3P]2TiCl6 was determined from X-ray diffraction data and refined to a residual index of R = 0.065. It crystallizes in the space group P2i/n with two formula units per unit cell; the cell dimensions are a - 921, b = 1314, c = 1648 pm and y - 100.87°. The TiCl62- ion occupies an inversion center and has the shape of a slightly distorted octahedron with Ti-Cl distances between 233 and 235 pm.


2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Ataf A. Altaf ◽  
Adnan Shahzad ◽  
Zarif Gul ◽  
Sher A. Khan ◽  
Amin Badshah ◽  
...  

1,3-Diisobutyl thiourea was synthesized and characterized by single crystal X-ray diffraction. It gives a monoclinic (α=γ= 90 andβ  ≠90) structure with the space group P21/c. The unit cell dimensions area= 11.5131 (4) Å,b= 9.2355 (3) Å,c= 11.3093 (5) Å,α= 90°,β= 99.569° (2),γ= 90°,V= 1185.78 (8) Å3, andZ= 4. The crystal packing is stabilized by intermolecular (N–H⋯S) hydrogen bonding in the molecules. The optimized geometry and Mullikan's charges of the said molecule calculated with the help of DFT using B3LYP-6-311G model support the crystal structure.


1986 ◽  
Vol 39 (12) ◽  
pp. 2145 ◽  
Author(s):  
MI Bruce ◽  
MR Snow ◽  
ERT Tiekink

The crystal structure of OsPt2(μ-CO)3(CO)2(PPh3)3 has been determined by single-crystal X-ray diffraction techniques. Crystals are triclinic, space group Pī with unit cell dimensions a 13.593(4), b 15.839(4), c 12.633(8) Ǻ, α 102.97(3), β 108.18(2), γ 84.86(3)° with Z2. The structure was refined by a full-matrix least-squares procedure on 5896 reflections [I ≥ 2.5σ(I)] to final R 0.028 and Rw 0.034. A triphenylphosphine ligand binds each of the metal atoms disposed at the corners of a triangle. Each metal-metal bond is spanned by a bridging carbonyl group. The coordination about the osmium atom is completed by two terminal carbonyl groups.


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