• 대한화학회지
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• 제14권1호
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• pp.123-126
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• 1970

The approximate crystal structure of benzidine monoperchlorate has been determined by single crystal X-Ray diffraction technique and patterson method. As the molecule has a center of symmetry in it and location of perchlorate ion is symmetrically on the mirror plane in the unit cell, perchlorate ion is forming hydrogen bond with two -$NH_2$ groups in the different molecule. Thus, one molecule of benzidine and perchloric acid combines 1:1 by mole ratio.

• Bulletin of the Korean Chemical Society
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• 제6권4호
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• pp.222-224
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• 1985

The crystal structure of sulindac, $C_{20}H_{17}Fo_3S$, one of the nonsteroid antiinflammatory agents, has been determined by the X-ray diffraction techniques using diffractometer data obtained by the $\varpi-2{\theta}$ scan technique with Cu $$K_{\alpha}$$ radiation from a crystal with space group symmetry Pbca and unit cell parameters a = 8.166(1), b = 18.291(8), c = 23.245(10) ${\AA}.$ The structure was solved by direct methods and refined by full-matrix least-squares to a final R = 0.11 for the 1153 observed reflections. The carboxyl group is nearly perpendicular to the indenyl ring as observed in indomethacin. The dihedral angle between the indenyl and phenyl rings is $35^{\circ}while$ the corresponding angle in indomethacin is $67^{\circ}.$ Crystal packing consists of a hydrogen bond and partial ring stacking between the indenyl rings.

• Archives of Pharmacal Research
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• 제11권2호
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• pp.127-133
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• 1988

The crystal structure of fenbufen was determined by X-ray diffraction techniuques. The compound was recrystallized in orthorhombic crystal system, space group $Pca2_1$ a = 31. 918(10), b = 5.550 (2), c = 15.078 (9) ${\AA}, D_m$= $1.26, {\D_x$= 1.264 g/$\textrm{cm}^3$, and Z = 8. The structure was solved by direct methods and refined by least squares procedure to the final R value of 0.051 for 1780 independent reflections. Two molecules in the asymmetric unit are related by a pseudo center of symmetry and dimerized via O-H...O hydrogen bonds. The carbonyl group attached to the phenyl ring is nearly coplanar to the ring. In the crystal the molecules are arranged in paralle stacks in the a direction.

• Bulletin of the Korean Chemical Society
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• 제5권4호
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• pp.158-162
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• 1984

The crystal structure of chloramphenicol base, $C_9H_{l2}N_2O_4$, the deacylated base of antibiotic chloramphenicol, has been determined by X-ray diffraction techniques using diffractometer data obtained by the ${\omega}-2{\theta}$ scan technique with CuK${\alpha}$ radiation from a crystal with space group symmetry $P2_12_12_1$ and unit cell parameters a = 22.322(6), b = 7.535(6), c = 5.781(5) ${\AA}$. The structure was solved by direct methods and refined by full-matrix least-squares to a final R = 0.051 for the 573 observed reflections. The overall conformation of the base is quite different from those of the chloramphenicol congeners which are similar despite the presence of many rotatable single bonds. The propane chain in the base is bent with respect to the phenyl ring, while it is extended in the chloramphenicol congeners. There is no intramolecular hydrogen bond between the hydroxyl groups of the propanediol moiety. All of the molecules in the crystal lattice are connected by a three-dimensional hydrogen bonding network.

• 비파괴검사학회지
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• 제36권1호
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• pp.1-8
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• 2016

Single crystalline silicon wafers having (100), (110), and (111) directions are employed as specimens for obtaining slowness profiles. Leaky Lamb waves (LLW) from immersed wafers were detected by varying the incident angles of the specimens and rotating the specimens. From an analysis of LLW signals for different propagation directions and phase velocities of each specimen, slowness profiles were obtained, which showed a unique symmetry with different symmetric axes. Slowness profiles were compared with elastic moduli of each wafer. They showed the same symmetries as crystal structures. In addition, slowness profiles showed expected patterns and values that can be inferred from elastic moduli. This implies that slowness profiles can be used to examine crystal structures of anisotropic solids.

• Bulletin of the Korean Chemical Society
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• 제4권2호
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• pp.79-83
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• 1983

The structure of thiamphenicol, one of the congeners of chloramphenicol which is a well-known antibiotic, has been determined by single crystal x-ray diffraction techniques. The crystal structure was determined using diffractometer data obtained by the $2{\theta}:{\omega}$ scan technique with $MoK{\alpha}$ radiation from a crystal having space group symmetry $P2_{1}2_{1}2_{1}$, and unit cell parameters a = 5.779, b = 15.292 and c = 17.322 ${\AA}$ . The structure was solved by direct methods and refined by least squares to an R = 0.070 for the 2116 reflections. The overall V-shaped conformation of thiamphenicol revealed in this study is consistent with those from the crystallographic studies and the proposed models from the theoretical and nmr studies of chloramphenicol. However there is no intramolecular hydrogen bond and the propanediol moiety is fully extended in the thiamphenicol molecule, while the crystal structures of chloramphenicol show the existence of the hydrogen bond between the two hydroxyl groups of the propanediol moiety forming an acyclic ring. All of the thiamphenicol molecules in the crystal are linked by a threedimensional hydrogen bonding network.

• Journal of Pharmaceutical Investigation
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• 제26권1호
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• pp.55-59
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• 1996

The crystal structure of diflunisal, 2',4'-difluoro-4-hydroxy-3-biphenyl-carboxylic acid, was determined by single crystal X-ray diffraction technique. The compound was recrystallized from a mixture of acetone and water in monoclinic, space group C2/c, with $a\;=\;34.666(6),\;b\;=\;3.743(1),\;c\;=\;20.737(4)\;{\AA},\;{\beta}=\;110.57(2)^{\circ}$, and Z = 8. The calculated density is $1.324\;g/cm^3$. The structure was solved by the direct method and refined by full matrix least-squares procedure to the final R value of 0.045 for 1299 observed reflections. It was found that the molecules in the crystal are partially disordered, that is, the two equivalent conformers $(180^{\circ}$ rotated ones through C(1)-C(7)) are packed alternatively without regular symmetry or sequence. The two phenyl rings of the biphenyl group is tilted to each other by the dihedral angle of $43.3^{\circ}$. The carboxyl group at the salicylic moiety is just coplanar to the phenyl ring, and the planarity of this salicylic moiety is stabilized by an intramolecular hydrogen bond of O(3)-H(O3) O(2). The molecules are dimerized through the intermolecular hydrogen bonds at the carboxyl group in the crystal.

• 한국초전도ㆍ저온공학회논문지
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• 제26권1호
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• pp.10-13
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• 2024

We performed angle-resolved Raman spectroscopy experiments on lead-doped and undoped Bi₂Sr₂CaCu₂O_8+δ(Bi2212) samples using a 660 nm laser and analyzed the Raman tensor of the phonon modes. The phonon mode was clearly observed at the 60, 103, and 630 cm^-1 Raman shifts. The 60, 630 cm^-1 peaks were only clearly observed when the incident and scattered light polarizations were configured to be parallel. The polarization angle dependence of the amplitude of the 60, 630 cm^-1 peak on the parallel configuration shows a twofold symmetry; therefore, both peaks originate from Ag phonons and the crystal structure of Bi2212 should be considered orthorhombic. On the other hand, the 103 cm^-1 peak is clearly observed in both parallel and perpendicular configurations. Remarkably, the off-diagonal component of the Raman tensor of the 103 cm^-1 peak showed an anti-symmetry that could not be realized within the known crystal structure of Bi2212. The implications of our findings are discussed.

• Bulletin of the Korean Chemical Society
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• 제4권3호
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• pp.123-127
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• 1983

The crystal structure of metoclopramide, $C_14H_22ClN_3O_2$, has been determined by X-ray diffraction techniques using diffractometer data obtained by the ${\omega}-2{\theta}$ scan technique with Mo $K\alpha$ radiation from a crystal with space group symmetry $P{\overline{1}}$ and unit cell parameters a = 7.500(1), b = 8.707(2), c = 13.292(2) ${\AA}$; ${\alpha}$ = 101.70(2), ${\beta}$ = 81.20(2), and ${\gamma}$ = $114.90(l)^{\circ}$. The sructure was solved by direct methods and refined by full-matrix least-squares to a final R = 0.055 for the 1524 observed reflections. The bent overall-conformation of the molecule seems to be determined mainly by the bifurcated intramolecular hydrogen bond from the amide nitrogen atom to the methoxy oxygen and the amine nitrogen atoms. The crystal packing consists of the hydrogen bonds, ${\pi}-{\pi}$ interaction and hydrophobic interaction.

• 한국결정학회지
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• 제6권2호
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• pp.75-79
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• 1995

The crystal structure of Tris(ethylenediamine)nickel(II)Chromate has been determined by X-ray crystallography. Crystal data : a=9.027(2)Å, c=9.751(5)Å이며, Z=2, V=687.9(2)Å3, Dc=1.714gcm-3, μ=21.635-1. The intensity were collected with Mo-Kα radiation (λ=0.7107Å) on an automatic four-circle diffractometer with a graphite monochromator. The structure was solved by Patterson method and refined by full matrix least-square methods using unit weights. The final R and S values were R=0.029, Rw=032, Rall=0.049 andS=0.018 for 342 observed reflections. The chromate ions are located at position of point of point symmetry 32 and their oxygens are sixfold disodered in an unusual way. Extensive strong hydrogen bonds between complex cations and chromatic anions are found in axial and equatorial directions.