منابع مشابه
A polymorph of terephthalaldehyde
A new ortho-rhom-bic polymorph of terephthalaldehyde, C(8)H(6)O(2), with a melting point of 372 K, has been obtained by recrystallization from ethanol. At room temperature, the crystals transform into the well known monoclinic form, with a melting point of 389 K. The crystal structure of the monoclinic form involves C-H⋯O hydrogen bonds, but no such bonds are observed in the orthorhombic form. ...
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The crystal structure of a previously unreported polymorph (form II) of 2,4-dinitro-phenyl-hydrazine (DNPH), C6H6N4O4, was determined at 90 K. The first polymorph (form I) is described in the monoclinic space group P21/c [Okabe et al. (1993 ▶). Acta Cryst. C49, 1678-1680; Wardell et al. (2006 ▶). Acta Cryst. C62, o318-320], whereas form II is in the monoclinic space group Cc. The mol-ecular str...
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The structure of the title compound, C(8)H(20)N(+)·Cl(-), is compared with a polymorph that was described earlier in the same space group. Differences in the conformations of the ethyl groups of the cation exist between the polymorphs. This study is given here in order to provide additional unit-cell data for use in qualitative identification of crystalline samples obtained in syntheses in whic...
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The title compound, C33H42O4 [systematic name: (1S,5S,7R)-3-benzoyl-4-hy-droxy-8,8-dimethyl-1,5,7-tris-(3-methyl-but-2--enyl)bi-cyclo-[3.3.1]nona-3-ene-2,9-dione], has a central bi-cyclo-[3.3.1]nonane-2,4,9-trione surrounded by tetra-prenyl-ated and benzoyl groups. The compound was recrystallized several times in methanol using both a slow evaporation method and with a crystal-seeding technique...
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A monoclinic polymorph of theophylline, C(7)H(8)N(4)O(2), has been obtained from a chloro-form/methanol mixture by evaporation under ambient conditions. The new polymorph crystallizes with two mol-ecules in the asymmetric unit. The structure features inter-molecular N-H⋯O hydrogen bonds, resulting in the formation of dimers between two crystallographically different mol-ecules; each mol-ecule a...
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ژورنال
عنوان ژورنال: Acta Crystallographica Section E Structure Reports Online
سال: 2013
ISSN: 1600-5368
DOI: 10.1107/s1600536813004571