Barrydawsonite-(Y), Na1.5CaY0.5Si3O9H: a new pyroxenoid of the pectolite–serandite group

2015 ◽  
Vol 79 (3) ◽  
pp. 671-686 ◽  
Author(s):  
R. H. Mitchell ◽  
M. D. Welch ◽  
A. R. Kampf ◽  
A. K. Chakhmouradian ◽  
J. Spratt
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Red Wine ◽  
Structural Formula ◽  
Potassium Feldspar ◽  
Monoclinic Space Group ◽  
Asymmetric Unit ◽  
X Ray ◽  
Final Agreement ◽  
Simplified Formula

AbstractThe new pyroxenoid barrydawsonite-(Y) occurs at the Merlot Claim, North Red Wine Pluton, Labrador, Canada (62°32'38.54'' W; 54°08'1.37'' N). The host rock is a metamorphosed eudialyte syenite consisting of eudialyte, potassic arfvedsonite, jadeitic aegirine, nepheline, albite and potassium feldspar with accessory Y-bearing pectolite, britholite and steenstrupine. Barrydawsonite-(Y) crystals commonly have discrete thin rims of Y-bearing pectolite. The average empirical formula (based on nine anions p.f.u.) is Na1.54Ca0.74Mn0.15Fe0.07Y0.38Nd0.01Sm0.01Gd0.02Tb0.01Dy0.04Ho0.01Er0.02Yb0.01Si3.00O9H. The simplified formula is Na1.5Y0.5CaSi3O9H. Barrydawsonite-(Y) is related to pectolite by the substitution ½[NaM3+Ca–2] (M3+ = Y,REE), and is exceptional in being the only member of the pectolite group that has the structure of the monoclinic M2abc polytype. The crystal structure has been determined in monoclinic space group P21/a: a = 15.5026(2), b = 7.0233(1), c = 6.9769(1) Å, β = 95.149(1)°, V = 756.58(2) Å3(Z = 4). Final agreement indices are R1 = 0.038, wR2 = 0.068, Goof = 1.136. The asymmetric unit of barrydawsonite-(Y) has three metal sites: M(1) = Ca, M(2) = Na0.5(Y,REE)0.5, M(3) = Na. M(1) and M(2) are octahedrally-coordinated sites, whereas M(3) is [8]-coordinated as in pectolite and serandite. The structural formula for the empirical composition is M(3)Na1.00M(2)(Na0.50Y0.38REE0.13)Σ=1.01M(1)(Na0.04Ca0.74Mn0.152+Fe0.072+)Σ=1.00Si3O9H. There is excellent agreement between the refined site-scattering values and those calculated based upon the structural formula.Barrydawsonite-(Y) is biaxial (+) with α = 1.612(1), β = 1.617(1), γ = 1.630(1) (white light) and 2V = 63(1)°. The five strongest peaks in the X-ray powder diffraction pattern are [dobs (Å), Iobs%, (hkl)]: [2.905, 100, (023)], [3.094, 30, (210,211,121,202)], [1.7613, 29, (127,323,040)], [3.272, 27, (202,104)], [1.7016, 27, (140,227,325)].

scholarly journals Powder study of 3-azabicyclo[3.3.1]nonane-2,4-dione form 2

2006 ◽  
Vol 62 (7) ◽  
pp. o3046-o3048 ◽  
Author(s):  
Ashley T Hulme ◽  
Philippe Fernandes ◽  
Alastair Florence ◽  
Andrea Johnston ◽  
Kenneth Shankland
Keyword(s):  
Crystal Structure ◽  
Simulated Annealing ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Title Compound ◽  
Variable Temperature ◽  
Polycrystalline Sample ◽  
Asymmetric Unit ◽  
X Ray ◽  
Compound C

A polycrystalline sample of a new polymorph of the title compound, C8H11NO2, was produced during a variable-temperature X-ray powder diffraction study. The crystal structure was solved at 1.67 Å resolution by simulated annealing from laboratory powder data collected at 250 K. Subsequent Rietveld refinement yielded an R wp of 0.070 to 1.54 Å resolution. The structure contains two molecules in the asymmetric unit, which form a C 2 2(8) chain motif via N—H...O hydrogen bonds.

Preparation and crystal structure of garnet-type calcium zirconium germanate Ca4ZrGe3O12

2016 ◽  
Vol 31 (4) ◽  
pp. 292-294 ◽  
Author(s):  
V. D. Zhuravlev ◽  
A. P. Tyutyunnik ◽  
N. I. Lobachevskaya
Keyword(s):  
Crystal Structure ◽  
Unit Cell Parameter ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Cell Parameter ◽  
Polycrystalline Sample ◽  
Structural Formula ◽  
Powder Diffraction Data ◽  
Structural Refinement ◽  
X Ray

A polycrystalline sample of Ca4ZrGe3O12 was synthesized using the nitrate–citrate method and heated at 850–1100 °C. Structural refinement based on X-ray powder diffraction data showed that the crystal structure is of the garnet type with a cubic unit-cell parameter [a = 12.71299(3) Å] and the space group Ia$\bar 3$d. The structural formula is presented as Ca3[CaZr]octa[Ge]tetraO12.

Studies on Crown Ether Complexes. XXXI. Synthesis, Properties and Structure of the Complexes of Lighter Lanthanide Nitrates With (Z)-2,3-Diphenyl-1,4,7,10,13-pentaoxacyclopentadec-2-ene (Stilbeno-15-crown-5)

1993 ◽  
Vol 46 (11) ◽  
pp. 1817 ◽  
Author(s):  
TB Lu ◽  
N Tang ◽  
MY Tan ◽  
Y Liu ◽  
KB Yu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Monoclinic Space Group ◽  
Asymmetric Unit ◽  
Conductivity Measurements ◽  
X Ray ◽  
Elemental Analyses ◽  
Crown Ether Complexes ◽  
Synthesis Properties ◽  
Lanthanide Nitrates ◽  
Ray Methods

Complexes of the lighter lanthanide nitrates with stilbeno-15-crown-5 (L) have been prepared in ethyl acetate. These new complexes with the general formula Ln (NO3)3.L.H2O ( Ln = La, Ce , Pr, Nd ) have been characterized by means of elemental analyses, i.r . spectra, 1H n.m.r. spectra and conductivity measurements. The crystal structure of La(NO3)3.L has been determined by X-ray methods, and refined to a residual R 0.0513 for 4937 independent reflections with I ≥ 1.5σ(I). It crystallizes in the monoclinic space group P21/a with a 16.090(5), b 15.654(8), c 22.687(2) Ǻ, β 93.96(4)°, V 5700(4)Ǻ3, and Z 8. There are two independent La(NO3)3.L monomers in one asymmetric unit; in each the coordination number is 11.

Powder X-ray diffraction of bendamustine hydrochloride monohydrate, C16H22Cl2N3O2Cl·H2O

2018 ◽  
Vol 34 (1) ◽  
pp. 74-75
Author(s):  
J. A. Kaduk ◽  
K. Zhong ◽  
T. N. Blanton ◽  
S. Gates-Rector ◽  
T. G. Fawcett
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Density Functional ◽  
Argonne National Laboratory ◽  
Lymphocytic Leukemia ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrochloride Monohydrate

Bendamustine hydrochloride monohydrate (marketed as Treanda®) is a nitrogen mustard purine analog alkylator used in the treatment of chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphomas. Commercial bendamustine hydrochloride monohydrate crystallizes in the monoclinic space group P21/c (14), with a = 4.71348(4) Å, b = 47.5325(3) Å, c = 8.97458 (5) Å, β = 96.6515(8)°, V = 1997.161(23) Å3, and Z = 4. A reduced cell search in the Cambridge Structural Database yielded a previously reported crystal structure (Allen, 2002), which did not include hydrogens (Reck, 2006). In this work, the sample was ordered from Santa Cruz Biotechnology, and analyzed as received. The room-temperature crystal structure was refined using synchrotron (λ = 0.413896 Å) powder diffraction data, density functional theory (DFT), and Rietveld refinement techniques. Hydrogen positions were included as part of the structure, and recalculated during the refinement. The diffraction data were collected on beamline BM-11 at the Advanced Photon Source, Argonne National Laboratory. Figure 1 shows the powder X-ray diffraction pattern of the compound. The pattern is included in the Powder Diffraction File as entry 00-064-1508.

Crystal structure study of selected xanthine derivatives

2010 ◽  
Vol 43 (1) ◽  
pp. 163-167 ◽  
Author(s):  
W. Lasocha ◽  
B. Gaweł ◽  
A. Rafalska-Lasocha ◽  
M. Pawłowski ◽  
P. Talik ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Powder Diffraction ◽  
Structure Study ◽  
Asymmetric Unit ◽  
Pharmaceutical Samples ◽  
X Ray ◽  
Xanthine Derivatives ◽  
Structure Solution ◽  
Theophylline Derivatives

The crystal structures of two compounds belonging to a group of theophylline derivatives have been solved by X-ray powder diffraction methods. Despite the fact that these compounds seemed to be rather simple (23 atoms in an asymmetric unit), the preferred orientation and dominant zone problems created very serious obstacles in the investigations, even for the most modern powder diffraction methods. The crystal structure of the first compound, 8-phenylazoxanthine, C14H14N6O2, was finally solved from laboratory diffractometer data, while in the case of the second compound, 8-(3-bromobenzylidene)xanthine, C15H14N5O2Br, it was not possible to reliably index its diffraction pattern until data had been collected at the high-resolution powder diffractometer ID31 at the ESRF Grenoble. The serious problems encountered during anab initiocrystal structure solution from powder data of these pharmaceutical samples are described and discussed.

scholarly journals Crystal structure solution of an elusive polymorph of Dibenzylsquaramide

2013 ◽  
Vol 28 (S2) ◽  
pp. S470-S480 ◽  
Author(s):  
Anna Portell ◽  
Xavier Alcobé ◽  
Latévi M. Lawson Daku ◽  
Radovan Černý ◽  
Rafel Prohens
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structural Features ◽  
Powder Diffraction Data ◽  
Asymmetric Unit ◽  
X Ray ◽  
The Third ◽  
Group Assignment ◽  
Structure Solution

The crystal structure of the third polymorph of dibenzylsquaramide (Portell, A. et al., 2009), (fig. 1) has been determined from laboratory X-ray powder diffraction data by means of direct space methods using the computing program FOX. (Favre-Nicolin and Černý, 2002) The structure resolution has not been straightforward due to several difficulties on the indexing process and in the space group assignment. The asymmetric unit contains two different conformers, which has implied an additional difficulty during the Rietveld (Rietveld, 1969) refinement. All these issues together with particular structural features of disquaramides are discussed.

The crystal structure of stilpnomelane. Part II. The full cell

1972 ◽  
Vol 38 (298) ◽  
pp. 693-711 ◽  
Author(s):  
R. A. Eggleton
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Structural Formula ◽  
Unit Cell ◽  
Octahedral Sheet ◽  
Tetrahedral Sheet ◽  
X Ray ◽  
Full Cell ◽  
Tetrahedral Layer ◽  
Silicon Oxygen

SummaryThe structural formula of stilpnomelane averaged from 37 representative literature analyses and based on the determined structure is (Ca,Na,K)4(Ti0·1Al2·3Fe35·5Mn0·8Mg9·3)[Si63Al9](O,OH)216·nH2O. Ferrostilpnomelanes have up to 12 R3+ cations in the octahedral sheet, ferristilpnomelanes commonly have between 24 and 30 R3+ cations, rarely up to 37. The two groups can be distinguished by accurate X-ray powder diffraction, ferrostilpnomelanes having d001 less and a greater than have ferristilpnomelanes. The unit cell is triclinic, a = b∼21·8 Å, γ = 120°, d001∼12·2 Å, P. Hexagonal groups or ‘islands’ of 24 silicon-oxygen tetrahedra co-ordinate to the octahedral sheet, the centres of the ‘islands’ are displaced by 5a/12, 8b/12 on either side of the octahedral sheet as a result of warping of this sheet to permit articulation with the smaller tetrahedral sheet. The 24-tetrahedra ‘islands’ are linked laterally by 6-member rings of inverted tetrahedra, which in turn link at their apices to like rings connecting the next sheet of ‘islands’. Thus a single tetrahedral layer is 4 tetrahedra thick and has symmetry 6/m. The 6-member rings of tetrahedra act as hinges permitting up to 0·5 Å extension or contraction of the tetrahedral sheet to accommodate variations in the octahedral sheet dimensions with varying R2+/R3+ ratio.

scholarly journals 4- and 5-Coordinate Dinuclear Copper(II) Complexes with the Tetraacetylethanediide and an N-Alkylated Diamine or a Triamine

1995 ◽  
Vol 50 (4) ◽  
pp. 536-544 ◽  
Author(s):  
Hide Kambayashi ◽  
Junko Yuzurihara ◽  
Yuichi Masuda ◽  
Hiroko Nakagawa ◽  
Wolfgang Linert ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Esr Spectra ◽  
Crystal Structure Analysis ◽  
Dinuclear Complex ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Dinuclear Copper ◽  
X Ray ◽  
Final Agreement

Six dinuclear copper(II) complexes have been prepared, Cu2(taet)(plam)2X2 where taet = 1,1,2,2-tetraacetylethanediide, plam = N-alkylated polyamine such as tmen = N,N,N′,N′-tetramethylethylenediamine or pmdt = N,N,N′,N′,N′-pentamethyldiethylenetriamine, X = a monovalent anion such as ClO4- , NO3- or Cl-. These complexes are classified into two categories from the results of electronic spectra, IR spectra, and X-ray single crystal structure analysis as follows: (1) 4-coordinate-4-coordinate dinuclear, [Cu2(taet)(tmen)2]X2 (where X = ClO4- or NO3-), (2) 5-coordinate-5-coordinate dinuclear, [Cu2(taet)(tmen)2Cl2], and [Cu2(taet)(pmdt)2]X2 (where X = ClO4-, NO3- , or Cl- ). The crystal structure of Cu2(taet)(tmen)2(ClO4)2 · H2O (1) has been determined by the single crystal X-ray diffraction technique; monoclinic space group P21/a with a = 26.478(3), b = 8.744(1), c = 15.601(3) Å, β = 106.195(9)°, and V = 3468.9(8) Å3 for Z = 4. The final agreement factors are R = 0.097 ( Rw = 0.099). The geometry of each Cu(II) moiety in the dinuclear cation (1) is 4-coordinate square planar with a N2O2 donor set. This tmen-dinuclear complex exhibits a very weak C u (II)-Cu (II) interaction (J = -0.5 cm-1), and shows characteristic ESR spectra with seven hyperfine peaks in 1,2-dichloroethane solution at room temperature. This is not found for the corresponding pmdt-dinuclear complex. All complexes obtained in this study are very soluble in many organic solvents. The tmen-dinuclear complexes show pronounced solvatochromic behavior-dependent on the solvent donor properties. This is not found for the corresponding pmdt-dinuclears, which are stable as 5-coordinated species.

The halotrichite group: the crystal structure of apjohnite

1976 ◽  
Vol 40 (314) ◽  
pp. 599-608 ◽  
Author(s):  
S. Menchetti ◽  
C. Sabelli
Keyword(s):  
Crystal Structure ◽  
Least Squares Method ◽  
Direct Methods ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Direct Connection ◽  
Asymmetric Unit ◽  
X Ray ◽  
Bonding System ◽  
Hydrogen Bonding System

SummaryApjohnite, MnAl2(SO4)4·22H2O, is monoclinic, space group P21/c, a 6·198 (2), b 24·347 (4), c 21·266 (4) Å, β 100·28 (3)° and Z = 4. The crystal structure was determined by means of direct methods applied to X-ray data collected with a single-crystal diffractometer. At the end of the refinement, performed with least-squares method, the R index was 0·039.The SO4 tetrahedra, Al(H2O)5 octahedra, and MnO(H2O)5 octahedra are connected by a hydrogen bonding system; the only direct connection between polyhedra is by sharing of an oxygen between S(4) and Mn. In the asymmetric unit there are twenty-two water molecules, five of which lie in channels of the structure and are not linked to the cations but only to ligand water oxygens by means of hydrogen bonds.Powder data indicate a close structural relationship between apjohnite, halotrichite, and pickeringite.

Ab initio determination and Rietveld refinement of the crystal structure of Ni0.50TiO(PO4)

1999 ◽  
Vol 14 (1) ◽  
pp. 10-15 ◽  
Author(s):  
P. Gravereau ◽  
J. P. Chaminade ◽  
B. Manoun ◽  
S. Krimi ◽  
A. El Jazouli
Keyword(s):  
Crystal Structure ◽  
Ab Initio ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Heavy Atom ◽  
Monoclinic Space Group ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Heavy Atom Method

The structure of the oxyphosphate Ni0.50TiO(PO4) has been determined ab initio from conventional X-ray powder diffraction data by the “heavy atom” method. The cell is monoclinic (space group P21/c, Z=4) with a=7.3830(5) Å, b=7.3226(5) Å, c=7.3444(5) Å, and β=120.233(6)°. Refinement of 46 parameters by the Rietveld method, using 645 reflexions, leads to cRwp=0.152, cRp=0.120, and RB=0.043. The structure of Ni0.50TiO(PO4) can be described as a TiOPO4 framework constituted by chains of tilted corner-sharing TiO6 octahedra running parallel to the c axis, crosslinked by phosphate tetrahedra and in which one-half of octahedral cavities created are occupied by Ni atoms. Ti atoms are displaced from the center of octahedra units in alternating long (2.231) and short (1.703 Å) Ti–O bonds along chains.

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