On the relationship between crystal structure and morphology; The anomalous crystal growth of potassium bichromate

1981 ◽  
Vol 54 (3) ◽  
pp. 541-545 ◽  
Author(s):  
Wilfried Wagner ◽  
Heinz Follner
Keyword(s):  
Crystal Structure ◽  
Crystal Growth ◽  
Potassium Bichromate ◽  
Structure And Morphology ◽  
The Relationship

Structure and Morphology of Metallic-Conductive Polyacetylene

1992 ◽  
Vol 247 ◽  
Author(s):  
Jun Tsukamoto ◽  
Akio Takahashi
Keyword(s):  
Crystal Structure ◽  
Electrical Properties ◽  
Resonance Raman ◽  
Granular Structure ◽  
X Ray Diffraction ◽  
Raman Analysis ◽  
X Ray ◽  
Sem Observation ◽  
Structure And Morphology ◽  
The Relationship

ABSTRACTWe have carried out structural analyses of highly conductive polyacetylene in order to elucidate the relationship between stucture and electrical properties. Sharp X-ray diffraction lines were observed for the heavily iodine-doped polyacetylene showing high conductivity, in contrast with the diffused diffractions of the conventional one. SEM observation reveals that granular structure of the new polyacetylene is composed of densely packed micro-fibrils. The result from the resonance Raman analysis indicates that the new cis-polyacetylene contains more longer conjugated segments than conventional polyacetylene. The relationship between the structure and conductivity is discussed, basing on the crystal structure and morphology observed.

Origin of low-symmetry growth sectors in edingtonite and yugawaralite, and crystal structure of the k{011} and v{120} sectors of yugawaralite

2002 ◽  
Vol 66 (3) ◽  
pp. 409-420 ◽  
Author(s):  
T. Tanaka ◽  
R. Kimura ◽  
M. Akizuki ◽  
Y. Kudoh
Keyword(s):  
Crystal Structure ◽  
Crystal Growth ◽  
Optical Microscopy ◽  
Interatomic Distances ◽  
Polarized Optical Microscopy ◽  
X Ray ◽  
Space Groups ◽  
The Relationship ◽  
Internal Texture ◽  
Low Symmetry

AbstractEdingtonite and yugawaralite showing sectoral textures were studied by polarized optical microscopy and X-ray analysis. In edingtonite, the m{110} sector (2Vα = 22°) is optically triclinic and the c{001} sector (2Vα = 52°) is orthorhombic. In yugawaralite, the k{011} sector is optically monoclinic, whereas the v{120} sector is triclinic. Their crystal structures were determined. The results of refinement showed that the space groups of the k{011} (Rw = 4.5%) and v{120} (Rw = 5.1%) growth sectors are monoclinic Pc and triclinic P1, respectively. In the v{120} sector, several interatomic distances, bond angles and site occupancies are different with respect to a symmetrical plane of the structure, and therefore the monoclinic c glide is extinct. Thus, the X-ray symmetry correlates with the optical one. From the relationship between the surface and internal texture, the symmetry and sector can be explained by cation (Al/Si) ordering during non-equilibrium crystal growth.

scholarly journals Nonlinear optical probes of nucleation and crystal growth: recent progress and future prospects

2021 ◽  
Author(s):  
Ahmet R. Dok ◽  
Thibaut Legat ◽  
Yovan de Coene ◽  
M. A. van der Veen ◽  
T. Verbiest ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Growth ◽  
Nonlinear Optical ◽  
Recent Progress ◽  
Future Prospects ◽  
Optical Probes ◽  
Optical Techniques ◽  
Structure And Morphology

Nonlinear optical techniques are emerging as powerful in-situ probes of crystallization processes due to their inherent sensitivity to crystal structure and morphology.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

Alkyl-chain disorder in tetraisohexylammonium bromide

2012 ◽  
Vol 68 (4) ◽  
pp. o152-o155 ◽  
Author(s):  
Malcolm A. Kelland ◽  
Amber L. Thompson
Keyword(s):  
Crystal Structure ◽  
Crystal Growth ◽  
Alkyl Chain ◽  
Growth Inhibitor ◽  
Ammonium Cation ◽  
Asymmetric Unit ◽  
Bromide Anion ◽  
Alkyl Chains ◽  
Hydrate Crystal ◽  
Structure Ii Clathrate Hydrate

Tetraisohexylammonium bromide [systematic name: tetrakis(4-methylpentyl)azanium bromide], C24H52N+·Br−, is a powerful structure II clathrate hydrate crystal-growth inhibitor. The crystal structure, in the space groupP3221, contains one ammonium cation and one bromide anion in the asymmetric unit, both on general positions. At 100 K, the ammonium cation exhibits one ordered isohexyl chain and three disordered isohexyl chains. At 250 K, all four isohexyl chains are disordered. In an effort to reduce the disorder in the alkyl chains, the crystal was thermally cycled, but the disorder remained, indicating that it is dynamic in nature.

scholarly journals Synthesis of magnesium carbonate hydrate from natural talc

2020 ◽  
Vol 18 (1) ◽  
pp. 951-961
Author(s):  
Qiuju Chen ◽  
Tao Hui ◽  
Hongjuan Sun ◽  
Tongjiang Peng ◽  
Wenjin Ding
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Crystal Growth ◽  
Crystal Morphology ◽  
Magnesium Carbonate ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
Morphological Transformation ◽  
X Ray ◽  
Carbonation Process

AbstractVarious morphologies of magnesium carbonate hydrate had been synthesized without using any organic additives by carefully adjusting the reaction temperature and time during the talc carbonation process. At lower temperatures, magnesium carbonate hydrate was prone to display needle-like morphology. With the further increase of the carbonation temperature, the sheet-like crystallites became the preferred morphology, and at higher aging temperatures, these crystallites tended to assemble into layer-like structures with diverse morphologies, such as rose-like particles and nest-like structure. The reaction time had no effect on the crystal morphology, but it affected the particle size and situation of the crystal growth. X-Ray diffraction results showed that these various morphologies were closely related to their crystal structure and compositions. The needle-like magnesium carbonate hydrate had a formula of MgCO3·3H2O, whereas with the morphological transformation from needle-like to sheet-like, rose-like, and nest-like structure, their corresponding compositions also changed from MgCO3·3H2O to 4MgCO3·Mg(OH)2·8H2O, 4MgCO3·Mg(OH)2·5H2O, and 4MgCO3·Mg(OH)2·4H2O.

scholarly journals Interaction of calcium ions and salivary acidic proline-rich proteins with hydroxyapatite. A possible aspect of inhibition of hydroxyapatite formation

1983 ◽  
Vol 213 (1) ◽  
pp. 11-20 ◽  
Author(s):  
A Bennick ◽  
D Kells ◽  
G Madapallimattam
Keyword(s):  
Crystal Growth ◽  
Calcium Ions ◽  
Binding Sites ◽  
Protein C ◽  
Tryptic Peptide ◽  
Protein A ◽  
Additional Amount ◽  
The Relationship ◽  
Surrounding Liquid ◽  
Hydroxyapatite Formation

The relationship between Ca2+- and hydroxyapatite-binding sites in salivary acidic proline-rich phosphoproteins A and C was investigated. Coating of hydroxyapatite with protein before adsorption had no effect on Ca2+ binding to the mineral, but simultaneous adsorption of Ca+ and protein to hydroxyapatite caused additional Ca2+ binding to the solid. The additional amount of Ca2+ adsorbed, measured in mol of Ca2+/mol of protein adsorbed to hydroxyapatite, was approx. 2 for protein C, 4 for protein A, 9 for the N-terminal tryptic peptide and 2 for dephosphorylated protein A. It is suggested that the ability of the proteins to inhibit hydroxyapatite formation is related to the binding of the proteins to crystal growth sites on the mineral, which prevents access of Ca2+ from the surrounding liquid.

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