• Title, Summary, Keyword: B20 crystal structure

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B20 Crystal Structure and Electromagnetic Property of MnGe and MnSi (B20 결정구조와 MnGe와 MnSi의 전자구조 및 자기적 특성)

  • Jeong, Tae Seong
    • Korean Journal of Materials Research
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    • v.29 no.8
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    • pp.477-482
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    • 2019
  • The magnetic properties and electronic structures of the B20 crystal structure MnGe and MnSi were investigated using the density functional theory with local density approximation. The low symmetry of the B20 crystal structure plays a very important role to make electromagnetic characteristics of these materials. The important result of the calculations is that it can be observed the appearance of a pair of gaps in the density of states near the Fermi level in both compounds. These features are results from d-band splitting by the low symmetry of the crystal field from B20 crystal structure. It can be seen that there is half-metallic characteristics from the density of states in both compounds. The calculation shows that the value of magnetic moment of MnGe is 5 times bigger than that of MnSi even though they have same crystal structure. The electronic structures of paramagnetic case have a very narrow indirect gap just above the Fermi level in both compounds. These gaps acquire some significance in establishing the stability of the ferromagnetic states within the local density approximation. Calculation shows that the Mn 3d character dominates the density of states near the Fermi level in both materials.

The synthesis and crystal structure of $[({\eta}^5-Cp)Co]_2$(1,2-S,S-o-Carborane) $(C_{12}H_{20}B_{10}S_2Co_2)$ ($[({\eta}^5-Cp)Co]_2$ (1,2-S,S-o-Carborane) $(C_{12}H_{20}B_{10}S_2Co_2)$의 합성 및 결정구조)

  • Cho, Sung-Il
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.18 no.2
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    • pp.62-67
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    • 2008
  • An Organometallic compound, $C_{12}H_{20}B_{10}S_2Co_2$, was synthesized from o-carborane, $Cp^*Co(S_2B_2B_{10}H_{10})$ and $BH_3{\cdot}THF$. The molecular structure of this complex has been determined by X-ray diffraction. Crystallographic data: monoclinic, space group Cc, a=15.981(4) ${\AA}$, b=15.478(17) ${\AA}$, c=12.0562(17) ${\AA}$, ${\beta}=115.063(16)^{\circ}$, Z=4, V=9683(4) ${\AA}^3$. The structure was solved by direct methods and refined by full-matrix leat-squares methods to give a model with a reliability factor R = 0.0630 for 9948 reflections.

The Crystal Structure of Licarin-B $(C_{20}H_{20}O_4)$, A Component of the Seeds of Myristica fragrans

  • Kim, Yang-Bae;Park, Il-Yeong;Shin, Kuk-Hyun
    • Archives of Pharmacal Research
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    • v.14 no.1
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    • pp.1-6
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    • 1991
  • The crystal structure of licarin-B, a component of Myristicae Semen was determined by single crystal X-ray diffraction analysis. Crystal of the compound, which was recrystallized from the mixture of hexane and ether, is monoclinic with a=12.740(1), b=7.219(1), c=9.284(1) ${\AA}$, ${\beta}=94.75(1)^{\circ}$, $D_x=1.26$, $D_m=1.27\;g/cm^3$, space group P21, and Z=2. The structure was solved by direct method and refined by least-squares procedure to the final R value of 0.040 for 1532 independent reflections ${F{\ge}3{\sigma}(F)}$. The compound is a dimeric phenylpropanoid, and belongs to the neolignan analogues. The molecules are arranged along with the screw axis. The intermolecular contacts appear to be the normal van der Waals' forces.

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The Growth and Optical Properties of $MgGa_2Se_4$ Single Crystal ($MgGa_2Se_4$ 단결정의 성장과 광학적 특성)

  • 김형곤;이광석;이기형
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.4
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    • pp.402-406
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    • 1988
  • The MgGa2Se4 single crystal for study of optical properties is for the first time grown by Bridgmna method. The crystal structure of grown MgGa2Se4 single crystal has the Rhomobohedral structure (R3m) and its lattice constant are a=3.950\ulcorner c=38.893\ulcornerin Hexagonal structure. The energy band structure of grown MgGa2Se4 single crystal structure has direct band gap and the optical energy gap measured from optical absorption in this crystal is 2.20eV at 290K. The temperature dependence of energy gap was given Eg(T)=Eg(O)-aT\ulcorner)B+T), from varshni equation, where Eg(O)=2.34eV, a=8.79x10**-4eV/and b=250K.

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The Crystal and Molecular Structure of Niclosamide monohydrate, $C_{13}H_8Cl_2N_2O_4\cdotH_2O$ (Niclosamide monohydrate, $C_{13}H_8Cl_2N_2O_4\cdotH_2O$의 결정 및 분자구조)

  • 김의성;신현소
    • Korean Journal of Crystallography
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    • v.4 no.1
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    • pp.1-5
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    • 1993
  • The crystal structure of N-(2'-chloro-4'-vitrophenyl)-5-chlorosalicylamide( Niclosamide ) monohydrate has been determined from 1976 sig- nificant independent reflections collected on an automated CAD4 diffractometer using graphitemonochromated Mo-Ka radiation. The crystal is monoclinic, space group P211c, with unit cell dimensions, a=11.331 (3), b=16.964(2), c=7.347(4)A , P =98.20(3)° and Z=4 at T=293k. The structure was solved by direct method using seminvariants of ggg Parity group and refined by the full-matrix least-square method, resulting model with reliability factor, R=0.046. The feature of the molecule show planar structure in parallel to the ab crystal plane.

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The Crystal Structure of One Natural Compound Cyclo-(1,10-Docandiamino-11,20-Docanedioic) Amide (1,12-Diazacyclodocosane-2,11-Dione)

  • Wei, Wan-Xing;Pan, Yuan-Jiang
    • Bulletin of the Korean Chemical Society
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    • v.23 no.11
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    • pp.1527-1530
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    • 2002
  • 1,12-diazacyclodocosane-2,11-dione was first isolated from a plant Phyllanthus niruri Linn. Its structure has been determined by means of spectroscopy methods and X-ray crystallography. Two peptide groups in the big ring (lactam) are the main factors influencing intermolecular contacts. The hydrogen-bond interaction of these hydrophilic groups is observed in the crystal structure. Meanwhile, C-H···O hydrogen bonds in molecules contribute to the formation of the whole crystal. These two kinds of hydrogen-bond form six- member rings among molecules. This compound crystallizes in the triclinic space group P-1 with a= 9.588(1) $\AA$, b= $9.850(1)\AA$, c = $11.810(1)\AA$, $\alpha=$ 68.18(1)$^{\circ}C$ , $\beta=$ 84.98(1), $\gamma$ = 86.03(1)$^{\circ}C$ , V = $1030.66(17)\AA3$ , Z = 2. A disorder of five-member carbon chain in the whole ring is observed in the title compound. The bond angle 105.8(4) is determined for a extreme configuration C(14)-C(15)-C(16), and 117.7(10) for another extreme configuration C(14')-C(15')-C(16'). In this crystal, two molecules are tied each other by short intermolecular hydrogen bonds, the oxygen atom being tied by hydrogen bond to nitrogen atom of another two molecules. The NMR and IR spectral data coincides to the structure of the compound.

Crystal and Molecular Structure of 12-(2-Methoxyphenyl)-9-[(4-methylbenzene)sulfonyl]-22-oxo-13,21-dioxa-9-azapentacyclo [12.8.0.02,11.03,8.015,20]docosa-1(14),3,5,7,15(20),16,18-heptaene-11-carbonitrile

  • Ganapathy, Jagadeesan;Damodharan, Kannan;Manickam, Bakthadoss;Sanmargam, Aravindhan
    • Journal of the Chosun Natural Science
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    • v.7 no.3
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    • pp.149-158
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    • 2014
  • The crystal structure of the title compounds with both coumarin and sulfonamide moieties were examined. These two groups have very special for their pharmaceutical and medicinal properties have been determined from single crystal X-ray diffraction data. In the title compound crystallizes in the monoclinic space group $P2_1/c$ with unit cell dimension a=$8.5775(4){{\AA}$, b=$24.9943(13){\AA}$ and c=$13.7319(7){\AA}$ [alpha & gamma=$90^{\circ}$ beta=$103.558(2)^{\circ}$]. In the structure The S1 atom shows a distorted tetrahedral geometry, with O1-S1-O2 [$121.08(1)^{\circ}$] and N1-S1-C5 [$105.85(1)^{\circ}$] angles deviating from ideal tetrahedral values are attributed to the Thrope-Ingold effect. The sum of bond angles around N1 ($354.9^{\circ}$) indicates that N1 is in $sp^2$ hybridization. The Pyridine ring adopts boat conformation and pyran rings adopt a sofa conformation. Crystal structure is stabilized by C-H...O intra molecular hydrogen bond interactions.

Crystal Structure Analysis of N,N'-bis(3-chloro-2-methylsalicylidene)-1,4-butanediamine

  • Sharmila, P.;Rajesh, R.;Venkatesan, R.;Ganapathy, Jagadeesan;Aravindhan, S.
    • Journal of the Chosun Natural Science
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    • v.9 no.4
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    • pp.255-260
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    • 2016
  • The crystal structure of the saliciline derivatives N,N'-bis(3-chloro-2-methylsalicylidene)-1,4-butanediamine ($C_{20}H_{22}Cl_2N_2O_2$) has been determined from single crystal X-ray diffraction data. In the title compound crystallizes in the triclinic space group $P{\bar{i}}$ with unit cell dimension $a=4.6085(3){\AA}$, $b=5.9747(3){\AA}$ and $c=5.9747(3){\AA}$ [${\alpha}=83.889(4)^{\circ}$, ${\beta}=86.744(5)^{\circ}$ and ${\gamma}=82.085(5)^{\circ}$]. The title compound is essentially planar conformation. The compound lies across a crystallographic inversion centre and adopts E configurations with respect to the C-N bonds. The crystal packing of the molecules of compound is stabilized through weak O-H...N intra molecular interactions

Synthesis and Characterization of Dinuclear Ni(II) Complexes with Tetraazadiphenol Macrocycle Bearing Cyclohexanes

  • Kim, Ki-Ju;Jung, Duk-Sang;Kim, Duk-Soo;Choi, Chi-Kyu;Park, Ki-Min;Byun, Jong-Chul
    • Bulletin of the Korean Chemical Society
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    • v.27 no.11
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    • pp.1747-1751
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    • 2006
  • The dinuclear tetraazadiphenol macrocyclic nickel(II) complexes [$Ni_2$([20]-DCHDC)]$Cl_2$ (I), [$Ni_2$([20]-DCHDC)]$(ClO_4)_2{\cdot}2CH_3CN $ (II(b)) and [$Ni_2$([20]-DCHDC)$(NCS)_2$] (III) {$H_2$[20]-DCHDC = 14,29-dimethyl-3,10,18,25-tetraazapentacyclo-[25,3,1,$0^{4,9}$,$1^{12,16}$,$0^{19,24}$]ditriacontane-2,10,12,14,16(32),17,27(31), 28,30-decane-31,32-diol} have been synthesized by self-assembly and characterized by elemental analyses, conductances, FT-IR and FAB-MS spectra, and single crystal X-ray diffraction. The crystal structure of II(b) is determined. It crystallizes in the monoclinic space group P2(1)/c. The coordination geometries around Ni(II) ions in I and II(b) are identical and square planes. In complex III each Ni(II) ion is coordinated to $N_2O_2$ plane from the macrocycle and N atoms of NCS- ions occupying the axial positions, forming a square pyramidal geometry. The nonbonded Ni…Ni intermetallic separation in the complex II(b) is 2.8078(10) $\AA$. The FAB mass spectra of I, II and III display major fragments at m/z 635.1, 699.4 and 662.4 corresponding to [$Ni_2$([20]-DCHDC)(Cl + 2H)]$^+$, [$Ni_2$([20]-DCHDC)$(ClO_4\;+\;2H)]^+$ and [$Ni_2$([20]-DCHDC)(NCS) + 6H]$^+$, respectively.