Single crystals of bacterial and synthetic poly(3-hydroxyvalerate)

1995 ◽  
Vol 41 (13) ◽  
pp. 297-302 ◽  
Author(s):  
R. H. Marchessault ◽  
E. M. Debzi ◽  
J. F. Revol ◽  
A. Steinbüchel
Keyword(s):  
Electron Diffraction ◽  
Single Crystals ◽  
Unit Cell ◽  
Orthorhombic Symmetry ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Fibre Diffraction ◽  
Diffraction Patterns

Lamellar, folded-chain single crystals of bacterial homopolymer, of synthetic racemic poly(β-hydroxyvalerate) (PHV), and of bacterial poly(β-hydroxybutyrate-co-(β-hydroxyvalerate) (P(HB-co-HV)), with high HV content (superior to 77 mol%) were obtained from dilute ethanolic solutions. They all exhibited the same square shape as opposed to the characteristic lath shape of poly(β-hydroxybutyrate) single crystals and P(HB-co-HV) single crystals with low HV content. The electron diffraction patterns recorded from selected areas of these single crystals were identical and allowed the comparison of our observed basal unit cell parameters with those derived from X-ray fibre diffraction. The results provided a visual and quantitative confirmation of the isodimorphism phenomenon and confirmed the P212121 orthorhombic symmetry. The lower perfection in the morphology of the single crystals from the synthetic PHV homopolymer than in those from the bacterial samples is attributable to a stereoblock segregation during the crystallization according to block chirality.Key words: poly(3-hydroxyvalerate), single crystals, bacterial polyester, electron diffraction, isodimorphism.

scholarly journals Bulachite, [Al6(AsO4)3(OH)9(H2O)4]⋅2H2O from Cap Garonne, France: Crystal structure and formation from a higher hydrate

2020 ◽  
Vol 84 (4) ◽  
pp. 608-615
Author(s):  
Ian E. Grey ◽  
Emre Yoruk ◽  
Stéphanie Kodjikian ◽  
Holger Klein ◽  
Catherine Bougerol ◽  
...  
Keyword(s):  
Unit Cell ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Different Temperatures ◽  
Using Data ◽  
Hydrated Aluminium

AbstractBulachite specimens from Cap Garonne, France, comprise two intimately mixed hydrated aluminium arsenate minerals with the same Al:As ratio of 2:1 and with different water contents. The crystal structures of both minerals have been solved using data from low-dose electron diffraction tomography combined with synchrotron powder X-ray diffraction. One of the minerals has the same powder X-ray diffraction pattern (PXRD) as for published bulachite. It has orthorhombic symmetry, space group Pnma with unit-cell parameters a = 15.3994(3), b = 17.6598(3), c = 7.8083(1) Å and Z = 4, with the formula [Al6(AsO4)3(OH)9(H2O)4]⋅2H2O. The second mineral is a higher hydrate with composition [Al6(AsO4)3(OH)9(H2O)4]⋅8H2O. It has the same Pnma space group and unit-cell parameters a = 19.855(4), b = 17.6933(11) and c = 7.7799(5) Å i.e. almost the same b and c parameters but a much larger a parameter. The structures are based on polyhedral layers, parallel to (100), of composition [Al6(AsO4)3(OH)9(H2O)4] and with H-bonded H2O between the layers. The layers contain [001] spiral chains of edge-shared octahedra, decorated with corner connected AsO4 tetrahedra that are the same as in the mineral liskeardite. The spiral chains are joined together by octahedral edge-sharing to form layers parallel to (100). Synchrotron PXRD patterns collected at different temperatures during heating of the specimen show that the higher-hydrate mineral starts transforming to bulachite when heated to 50°C, and the transformation is complete between 75 and 100°C.

Analysis of an industrial production suspension ofBacillus lentussubtilisin crystals by powder diffraction: a powerful quality-control tool

2014 ◽  
Vol 70 (4) ◽  
pp. 1115-1123 ◽  
Author(s):  
Christian G. Frankaer ◽  
Olga V. Moroz ◽  
Johan P. Turkenburg ◽  
Stein I. Aspmo ◽  
Majbritt Thymark ◽  
...  
Keyword(s):  
Quality Control ◽  
Single Crystals ◽  
Powder Diffraction ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Quality Control Tool ◽  
Control Tool

A microcrystalline suspension ofBacillus lentussubtilisin (Savinase) produced during industrial large-scale production was analysed by X-ray powder diffraction (XRPD) and X-ray single-crystal diffraction (MX). XRPD established that the bulk microcrystal sample representative of the entire production suspension corresponded to space groupP212121, with unit-cell parametersa= 47.65,b= 62.43,c= 75.74 Å, equivalent to those for a known orthorhombic crystal form (PDB entry 1ndq). MX using synchrotron beamlines at the Diamond Light Source with beam dimensions of 20 × 20 µm was subsequently used to study the largest crystals present in the suspension, with diffraction data being collected from two single crystals (∼20 × 20 × 60 µm) to resolutions of 1.40 and 1.57 Å, respectively. Both structures also belonged to space groupP212121, but were quite distinct from the dominant form identified by XRPD, with unit-cell parametersa= 53.04,b = 57.55,c= 71.37 Å anda= 52.72,b= 57.13,c= 65.86 Å, respectively, and refined toR= 10.8% andRfree= 15.5% and toR= 14.1% andRfree= 18.0%, respectively. They are also different from any of the forms previously reported in the PDB. A controlled crystallization experiment with a highly purified Savinase sample allowed the growth of single crystals of the form identified by XRPD; their structure was solved and refined to a resolution of 1.17 Å with anRof 9.2% and anRfreeof 11.8%. Thus, there are at least three polymorphs present in the production suspension, albeit with the 1ndq-like microcrystals predominating. It is shown how the two techniques can provide invaluable and complementary information for such a production suspension and it is proposed that XRPD provides an excellent quality-control tool for such suspensions.

X-ray powder diffraction data of anilinium trimolybdate tetrahydrate and anilinium trimolybdate dihydrate

1999 ◽  
Vol 14 (4) ◽  
pp. 280-283 ◽  
Author(s):  
A. Rafalska-Łasocha ◽  
W. Łasocha ◽  
M. Michalec
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Room Temperature ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns

The X-ray powder diffraction patterns of anilinium trimolybdate tetrahydrate, (C6H5NH3)2Mo3O10·4H2O, and anilinium trimolybdate dihyhydrate, (C6H5NH3)2Mo3O10·2H2O, have been measured in room temperature. The unit cell parameters were refined to a=11.0670(7) Å, b=7.6116(8) Å, c=25.554(3) Å, space group Pnma(62) and a=17.560(2) Å, b=7.5621(6) Å, c=16.284(2) Å, β=108.54(1)°, space group P21(4) or P21/m(11) for orthorhombic anilinium trimolybdate tetrahydrate and monoclinic anilinium trimolybdate dihydrate, respectively.

New Applications of Electron Diffraction in the Pharmaceutical Industry: Polymorph Determination by Using a Combination of Electron Diffraction and Synchrotron X-ray Powder Diffraction Techniques

2002 ◽  
Vol 8 (2) ◽  
pp. 134-138 ◽  
Author(s):  
Z.G. Li ◽  
R.L. Harlow ◽  
C.M. Foris ◽  
H. Li ◽  
P. Ma ◽  
...  
Keyword(s):  
Pharmaceutical Industry ◽  
Electron Diffraction ◽  
Powder Diffraction ◽  
Unit Cell ◽  
X Ray ◽  
Cell Parameters ◽  
Synchrotron Powder Diffraction ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
New Applications

Electron diffraction has been recently used in the pharmaceutical industry to study the polymorphism in crystalline drug substances. While conventional X-ray diffraction patterns could not be used to determine the cell parameters of two forms of the microcrystalline GP IIb/IIIa receptor antagonist roxifiban, a combination of electron single-crystal and synchrotron powder diffraction techniques were able to clearly distinguish the two polymorphs. The unit-cell parameters of the two polymorphs were ultimately determined using new software routines designed to take advantage of each technique's unique capabilities. The combined use of transmission electron microscopy (TEM) and synchrotron patterns appears to be a good general approach for characterizing complex (low-symmetry, large-unit-cell, micron-sized) polymorphic pharmaceutical compounds.

Powder-Pattern: A System of Programs for Processing and Interpreting Powder Diffraction Data

1982 ◽  
Vol 26 ◽  
pp. 63-72 ◽  
Author(s):  
Nikos P. Pyrros ◽  
Camden R. Hubbard
Keyword(s):  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Pure Phase ◽  
Diffraction Patterns ◽  
Better Than ◽  
Good Agreement

The production of standard x-ray diffraction patterns at NBS imposes special requirements in the data processing of powder patterns. The patterns should be complete and have an overall accuracy of better than 0.01 degree two theta. To ensure completeness all the observable peaks should be indexed. To make certain that the sample is a pure phase, weak peaks have to be identified as well.The indexing of all the peaks implies that the cell constants must be known and there should be a good agreement between all the calculated and observed peak positions. In practice this is achieved by a least-squares refinement of the unit cell parameters. This serves as a test of the assumed unit cell and also as an interpretation of the observed peaks. Finally, an attempt is made to identify the space group. This step also requires the identification of weak peaks. The agreement of a known space group with the observed reflections further confirms the purity of the sample.

X-ray powder diffraction pattern for lactitol and lactitol monohydrate

1994 ◽  
Vol 9 (3) ◽  
pp. 213-216 ◽  
Author(s):  
J. Valkonen ◽  
P. Perkkalainen ◽  
I. Pitkänen ◽  
H. Rautiainen
Keyword(s):  
Powder Diffraction ◽  
Least Squares Method ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Cell Dimensions ◽  
Diffraction Patterns ◽  
Unit Cell Dimensions

Diffraction patterns were recorded, and unit cell dimensions refined by the least-squares method, for lactitol and lactitol monohydrate. Refined unit cell parameters for lactitol are: a =7.622(1) Å, b = 10.764(2) Å, c = 9.375(1) Å, β= 108.25(1)° in space group P21, and those for lactitol monohydrate a =7.844(1) Å, b = 12.673(2) Å, c = 15.942(2) Å in space group P212121.

X-ray powder diffraction data for five lanthanoid chromates [Ln2(CrO4)3(H2O)5]·2H2O (Ln=La,Pr,Nd,Sm,Eu)

1994 ◽  
Vol 9 (2) ◽  
pp. 98-104
Author(s):  
Jaakko Leppä-aho ◽  
Jussi Valkonen
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns

X-ray powder diffraction data are reported for a series of isomorphous compounds of [Ln2(CrO4)3(H2O)5]·2H2O, where Ln=La, Pr, Nd, Sm, or Eu. The compounds crystallize in monoclinic space group P21/c (No: 14) with Z=4. Refined unit cell parameters and indexed powder diffraction patterns are given.

Structure Studies of Electrodeposited Ni-Mo Alloys with Polymers after Annealing

2007 ◽  
Vol 130 ◽  
pp. 97-100 ◽  
Author(s):  
Małgorzata Karolus ◽  
Edward Rówiński ◽  
Eugeniusz Łągiewka
Keyword(s):  
Solid Solution ◽  
Steel Substrate ◽  
Argon Atmosphere ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Air Atmosphere ◽  
Diffraction Patterns

Electrolytical layers of Ni-Mo alloys with polypyrrole, polytiofene and polyethylene were deposited on steel substrate (St3S, 4 cm2). After structural analyses of as quenched samples performed by X-ray diffraction it was noticed that the solid solution of Mo in Ni is observed. After annealing in an argon atmosphere the solid solution of Mo in Ni is becomeing more stable and crystalites are growing to the size of 200 – 300 Å. After annealing in an air atmosphere X-ray diffraction patterns show presence of phases: NiO, MoO, NiCO3, Mo2N. The unit cell parameters of solid solution after annealing are smaller than parameters of as quenched samples what means that the solid solution has been decomposing.

Crystal data for benzofuroin

1983 ◽  
Vol 16 (1) ◽  
pp. 140-140
Author(s):  
O. Durruthy ◽  
F. Fajardo ◽  
R. Pomes
Keyword(s):  
Powder Diffraction ◽  
Unit Cell ◽  
Crystal Data ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns

Benzofuroin crystal data were obtained from X-ray powder diffraction patterns. Benzofuroin, C12H10O3, is monoclinic P21/c, with unit-cell parameters a = 10.672 (3), b = 16.521 (4), c = 5.586 (1) Å and γ = 110.45 (3)°, V= 922.8 (10) Å3, Z = 4, Dx = 1.45 Mgm−3.

Microstructural evolution of mullites produced from single-phase gels

2007 ◽  
Vol 40 (2) ◽  
pp. 260-276 ◽  
Author(s):  
Marek Andrzej Kojdecki ◽  
Esther Ruiz de Sola ◽  
Francisco Javier Serrano ◽  
Estefanía Delgado-Pinar ◽  
María Mercedes Reventós ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Unit Cell ◽  
Molar Ratio ◽  
Model Parameters ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Transmission Electron ◽  
Diffraction Patterns

The crystalline microstructure of mullites obtained by heating monophasic gels has been investigated. Gels with alumina to silica molar ratio of 3:2 (as in secondary mullite) and 2:1 (as in primary mullite) were prepared by gelling mixtures of aluminium nitrate and tetraethylorthosilicate. Phase transformations were induced by heating the gel precursors, with different final treatment temperatures between 1173 and 1873 K. The mullites formed as a result of thermal treatment were studied by means of X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The crystalline structure (unit-cell parameters) and microstructure were determined from X-ray diffraction patterns. The formation of mullites of homogeneous chemical composition and with unit-cell parameters depending almost linearly on the treatment temperature was found. Their compositions, expressed as alumina to silica molar ratio, were determined from the unit-cell parameters and were in the range of those characterizing primary and secondary mullites. Mullites processed at lower temperatures were accompanied by small amounts of vitreous phase. The crystalline microstructure of the obtained mullites was interpreted by means of a mathematical model of polycrystalline material, involving prevalent crystallite shape, volume-weighted crystallite size distribution and second-order crystalline lattice strain distribution as model parameters. The model parameters were determined for each sample by modelling its X-ray diffraction pattern and fitting it to a measured pattern. Bimodality of the size distribution was observed and explained as a consequence of two crystallite nucleation and growth processes, which started from small alumina-rich and alumina-poor domains, spontaneously formed in a precursor gel at early stages of heating. Images produced by scanning and transmission electron microscopy agreed well with the characteristics obtained from the analysis of the X-ray diffraction patterns.

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