scholarly journals Supplemental Material: Protogenetic sulfide inclusions in diamonds date the diamond formation event using Re-Os isotopes

2021 ◽  
Author(s):  
Martha Pamato ◽  
et al.
Keyword(s):  
Single Crystals ◽  
Diffusion Model ◽  
Unit Cell ◽  
Diamond Formation ◽  
Unit Cell Parameters ◽  
Rietveld Refinements ◽  
Cell Parameters ◽  
Model Unit ◽  
Os Isotopes ◽  
Crystallographic Orientations

Description of Rietveld refinements and composition of the Mss, reciprocal crystallographic orientations and Os diffusion model, unit-cell parameters of pyrrhotite single crystals, and orientation matrices for both inclusions and hosts.<br>

scholarly journals Supplemental Material: Protogenetic sulfide inclusions in diamonds date the diamond formation event using Re-Os isotopes

2021 ◽  
Author(s):  
Martha Pamato ◽  
et al.
Keyword(s):  
Single Crystals ◽  
Diffusion Model ◽  
Unit Cell ◽  
Diamond Formation ◽  
Unit Cell Parameters ◽  
Rietveld Refinements ◽  
Cell Parameters ◽  
Model Unit ◽  
Os Isotopes ◽  
Crystallographic Orientations

Description of Rietveld refinements and composition of the Mss, reciprocal crystallographic orientations and Os diffusion model, unit-cell parameters of pyrrhotite single crystals, and orientation matrices for both inclusions and hosts.<br>

On the accuracy of determining the unit cell parameters of single crystals on modern laboratory diffractometers

2021 ◽  
Vol 62 (5) ◽  
Author(s):  
П.C. Серебренникова ◽  
В.Ю. Комаров ◽  
А.С. Сухих ◽  
С.А. Громилов
Keyword(s):  
Single Crystals ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Cell Parameters

scholarly journals The crystal structure of alstonite, BaCa(CO3)2: an extraordinary example of ‘hidden’ complex twinning in large single crystals

2020 ◽  
Vol 84 (5) ◽  
pp. 699-704
Author(s):  
Luca Bindi ◽  
Andrew C. Roberts ◽  
Cristian Biagioni
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Structure Determination ◽  
Unit Cell ◽  
Crystal Structure Determination ◽  
Unit Cell Parameters ◽  
Space Group ◽  
Cell Parameters ◽  
Structure Determinations

AbstractAlstonite, BaCa(CO3)2, is a mineral described almost two centuries ago. It is widespread in Nature and forms magnificent cm-sized crystals. Notwithstanding, its crystal structure was still unknown. Here, we report the crystal-structure determination of the mineral and discuss it in relationship to other polymorphs of BaCa(CO3)2. Alstonite is trigonal, space group P31m, with unit-cell parameters a = 17.4360(6), c = 6.1295(2) Å, V = 1613.80(9) Å3 and Z = 12. The crystal structure was solved and refined to R1 = 0.0727 on the basis of 4515 reflections with Fo > 4σ(Fo) and 195 refined parameters. Alstonite is formed by the alternation, along c, of Ba-dominant and Ca-dominant layers, separated by CO3 groups parallel to {0001}. The main take-home message is to show that not all structure determinations of minerals/compounds can be solved routinely. Some crystals, even large ones displaying excellent diffraction quality, can be twinned in complex ways, thus making their study a crystallographic challenge.

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.

ON THE ACCURACY OF DETERMINING UNIT CELL PARAMETERS OF SINGLE CRYSTALS ON MODERN LABORATORY DIFFRACTOMETERS

2021 ◽  
Vol 62 (5) ◽  
pp. 682-691
Author(s):  
P. C. Serebrennikova ◽  
V. Yu. Komarov ◽  
A. S. Sukhikh ◽  
S. A. Gromilov
Keyword(s):  
Single Crystals ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Cell Parameters

Crystal-structure analysis of four mineral samples of anhydrite, CaSO4, using synchrotron high-resolution powder X-ray diffraction data

2011 ◽  
Vol 26 (4) ◽  
pp. 326-330 ◽  
Author(s):  
Sytle M. Antao
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Unit Cell Volume ◽  
Crystal Structure Analysis ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Rietveld Refinements ◽  
X Ray ◽  
Cell Parameters

The crystal structures of four samples of anhydrite, CaSO4, were obtained by Rietveld refinements using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data and space group Amma. As an example, for one sample of anhydrite from Hants County, Nova Scotia, the unit-cell parameters are a = 7.00032(2), b = 6.99234(1), c = 6.24097(1) Å, and V = 305.487(1) Å3 with a > b. The eight-coordinated Ca atom has an average <Ca-O> distance of 2.4667(4) Å. The tetrahedral SO4 group has two independent S-O distances of 1.484(1) to O1 and 1.478(1) Å to O2 and an average <S-O> distance of 1.4810(5) Å. The three independent O-S-O angles [108.99(8) × 1, 110.38(3) × 4, 106.34(9)° × 1; average <O-S-O> [6] = 109.47(2)°] and S-O distances indicate that the geometry of the SO4 group is quite distorted in anhydrite. The four anhydrite samples have structural trends where the a, b, and c unit-cell parameters increase linearly with increasing unit-cell volume, V, and their average <Ca-O> and <S-O> distances are nearly constant. The grand mean <Ca-O> = 2.4660(2) Å, and grand mean <S-O> = 1.4848(3) Å, the latter is longer than 1.480(1) Å in celestite, SrSO4, as expected.

Synthesis and Rietveld refinements of monoclinic Er2BaF8

2004 ◽  
Vol 19 (3) ◽  
pp. 265-269 ◽  
Author(s):  
S. N. Achary ◽  
M. D. Mathews ◽  
A. K. Tyagi
Keyword(s):  
Diffraction Data ◽  
Polycrystalline Sample ◽  
Rietveld Analysis ◽  
Unit Cell ◽  
Quartz Ampoule ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Rietveld Refinements ◽  
Cell Parameters ◽  
Monoclinic Lattice

The compound Er2BaF8 is prepared by heating appropriate amounts of BaF2 and ErF3 at 900 °C for 18 h in a dry argon filled quartz ampoule. The polycrystalline sample obtained was characterized by a Rietveld refinement of the observed powder diffraction data. This compound crystallizes in a monoclinic lattice with unit cell parameters: a=6.9620(2), b=10.4960(3), c=4.2541(1) Å and β=99.685(1)°, V=306.14(1) Å3, Z=2, (space group C 2/m, No. 12). The structure analysis reveals the presence of one kind of Ba and Er atoms in the unit cell. There are three different kinds of fluorine atoms, namely F1, F2, and F3 in the ratio of 8:4:4. The Er atoms form a square-antiprism polyhedron with eight fluorine atoms, which share three of its edges to form a ring of six ErF8 polyhedra. The rings of ErF8 polyhedra are connected via two opposite corners along the c-axis of the unit cell. The voids formed within the rings are occupied by Ba atoms, which maintain a twelve-coordination polyhedron with the fluorine atoms. As per the Rietveld analysis, the F3 site may exist as a disordered state by shifting the fluorine atom from the two-fold axes. © 2004 International Centre for Diffraction Data.

Crystal structure of semiorganic antimony thiourea bromide monohydrate crystals: a redetermination

2009 ◽  
Vol 87 (4) ◽  
pp. 345-348 ◽  
Author(s):  
Mahesha K. Upadhya ◽  
N. K. Udayashankar
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Room Temperature ◽  
Direct Methods ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Orthorhombic Space Group ◽  
Cell Parameters ◽  
Evaporation Technique ◽  
R Value

The growth of antimony thiourea bromide monohydrate (ATBM) single crystals by evaporation technique at room temperature is reported here. Antimony thiourea bromide monohydrate crystallizes in the orthorhombic space group Cmca with unit cell parameters a = 12.320(7) Å, b = 11.668(7) Å, c = 18.615(11), and z = 8. The structure has been solved by direct methods and refined to a final R value of 0.0239.

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