نتایج جستجو برای: polymorph

تعداد نتایج: 2081  

Journal: :CrystEngComm 2021

A new polymorph of tolfenamic acid, form IX, has been crystallised from a simple cooling crystallisation experiment raising the question as to why this had never reported before.

2012
Meenesh R. Singh Jayanta Chakraborty Nandkishor Nere Hsien-Hsin Tung Shailendra Bordawekar Doraiswami Ramkrishna

A new technique for the measurement of 3D crystal morphology and identification of its polymorph using tomographic images is proposed. Confocal microscopy is used for the first time to obtain tomographic images of crystals that are coated with a suitable fluorescent dye. A convex polyhedron is fitted through a stack of tomographic images of a crystal to obtain the normal vectors of each facet a...

Journal: :Mineralogy and petrology 2014
Udo Haefeker Reinhard Kaindl Peter Tropper Hannes Krüger Volker Kahlenberg Maria Orlova

The crystal structures of synthetic hexagonal and orthorhombic Fe-cordierite polymorphs with the space groups P6/mcc and Cccm were refined from single-crystal X-ray diffraction data to R1, hex = 3.14 % and R1, ortho = 4.48 %. The substitution of the larger Fe2+ for Mg leads to multiple structural changes and an increase of the unit cell volumes, with a, c (hex) = 9.8801(16) Å, 9.2852(5) Å and a...

Journal: :Acta crystallographica. Section C, Crystal structure communications 2005
Gary S Nichol William Clegg

Vigorous reaction of barbituric acid with caesium hydroxide in water resulted in an unexpected coupling product, 5-hydroxyhydurilic acid, complexed to caesium, giving poly[[caesium-mu5-5-hydroxyhydurilato] hemihydrate], {[Cs(C8H5N4O7)].0.5H2O}n. This was obtained in two different polymorphic forms, depending on the method of crystal growth. Slow solvent evaporation yielded an orthorhombic polym...

Journal: :Dalton transactions 2004
Andrew E Whitten Birger Dittrich Mark A Spackman Peter Turner Trevor C Brown

High-resolution X-ray diffraction data have been collected on the cubic polymorph of antimony(III) oxide (senarmontite) to determine the charge distribution in the crystal. The results are in quantitative agreement with crystal Hartree-Fock calculations for this polymorph, and have been compared with theoretical calculations on the orthorhombic polymorph (valentinite). Information about the nat...

Journal: :Chemical communications 2007
Marta Dabros Venkat R Thalladi

Carboxy terminated alkanethiol self-assembled monolayers promote the face-selective nucleation of the P-monoclinic polymorph of carbamazepine; the type of face nucleated depends on the parity of the alkyl chain.

2013
Kiichi Amimoto Hiromitsu Nishiguchi

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...

2009
Yong Yan Joel T. Mague James P. Donahue

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...

Journal: :Archives of disease in childhood 1981
R J Levinsky B A Harvey D M Roberton O H Wolff

We describe a child with primary defect of polymorph bacterial killing associated with systemic lungs erythematosus. We suggest that her autoimmune disease results from chronic bacterial antigen stimulation and propose a hypothetical model linking immunodeficiency with autoimmunity.

Journal: :Chemical communications 2009
Leo Merz Tobias Bauert Manfred Parschau Georg Koller Jay S Siegel Karl-Heinz Ernst

A phase transition between two-dimensional polymorphs of the buckybowl corannulene on a Cu(111) surface can be suppressed by spatial confinement, allowing stabilisation of the metastable polymorph over the stable one.

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