Alluaudite-Group Phosphate and Arsenate Minerals

2021 ◽  
Author(s):  
Kimberly T. Tait ◽  
Frank C. Hawthorne ◽  
Norman M. Halden
Keyword(s):  
Single Crystal ◽  
Structural Formula ◽  
Synthesis Methods ◽  
X Ray Diffraction ◽  
Ionic Radii ◽  
X Ray ◽  
International Mineralogical Association ◽  
Graphite Monochromator ◽  
Wide Range

ABSTRACT A systematic study of alluaudite, hagendorfite, and varulite was done using single-crystal X-ray diffraction, powder diffraction, and electron probe microanalysis of samples from 12 separate localities. The crystal structures of the representative alluaudite and hagendorfite samples were refined to R1 indices of 3.7 and 1.8%, respectively, using a Siemens P4 automated four-circle diffractometer equipped with a graphite monochromator and MoKα X-radiation. These samples and several others were analyzed with an electron microprobe to study variations in chemical composition. For the single-crystal analyses, the resulting unit formulae are (Na0.11□0.89)(Na0.59Mn0.27Ca0.14)Mn1.00(Fe3+1.64Al0.24Mg0.13)(PO4)3 for alluaudite, (Na0.79□0.21)(Na0.81Mn2+0.19)(Mn0.70Fe2+0.30)(Fe2+1.72Mg0.27Al0.01)(PO4)3 for hagendorfite, and (Na0.84□0.16)(Na0.71Ca0.23□0.06)Mn1.00(Fe3+0.89Fe2+0.68Mn0.42Mg0.01)(PO4)3 for varulite. Originally, a nomenclature scheme was proposed for the alluaudite-group minerals that was based on sequentially distributing the cations in the cell according to increasing polyhedron size, matching that size with increasing ionic radii of the cations. For alluaudite, the structural formula was written as X(2)4X(1)4M(1)4M(2)8(PO4)12, with the sites ordered in decreasing size of the discrete polyhedra. Later, the formula [A(2)A(2)'A(2)”2][A(1)A(1)'A(1)”2]M(1)M(2)2(PO4)3 was proposed, which takes into account the distinct crystallographic sites in the channels of the structure. More recently there has been a revision to the nomenclature of the group. The simplified structural formula for the alluaudite-type is now A(2)'A(1)M(1)M(2)2(TO4)3; the new nomenclature scheme has been adopted by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA-CNMNC), based on the contents of the M(1) and M(2) octahedral sites, and the results are reviewed here. Compounds belonging to the alluaudite structural family have been the focus of synthetic mineral studies for decades owing to the open-framework architecture and their unique physical properties. Improvements in synthesis methods have allowed researchers to substitute a wide range of elements into the alluaudite structure.

scholarly journals Kishonite, VH2, and Oreillyite, Cr2N, Two New Minerals from the Corundum Xenocrysts of Mt Carmel, Northern Israel

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1118
Author(s):  
Luca Bindi ◽  
Fernando Cámara ◽  
Sarah E. M. Gain ◽  
William L. Griffin ◽  
Jin-Xiang Huang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Volatile Species ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
International Mineralogical Association ◽  
Mineralogical Association ◽  
Transmission Electron ◽  
Deep Earth

Here, we describe two new minerals, kishonite (VH2) and oreillyite (Cr2N), found in xenoliths occurring in pyroclastic ejecta of small Cretaceous basaltic volcanoes exposed on Mount Carmel, Northern Israel. Kishonite was studied by single-crystal X-ray diffraction and was found to be cubic, space group Fm3¯m, with a = 4.2680(10) Å, V = 77.75(3) Å3, and Z = 4. Oreillyite was studied by both single-crystal X-ray diffraction and transmission electron microscopy and was found to be trigonal, space group P3¯1m, with a = 4.7853(5) Å, c = 4.4630(6) Å, V = 88.51 Å3, and Z = 3. The presence of such a mineralization in these xenoliths supports the idea of the presence of reduced fluids in the sublithospheric mantle influencing the transport of volatile species (e.g., C, H) from the deep Earth to the surface. The minerals and their names have been approved by the Commission of New Minerals, Nomenclature and Classification of the International Mineralogical Association (No. 2020-023 and 2020-030a).

scholarly journals High pressure studies of L-Serine-L-Ascorbic acid co-crystal

2014 ◽  
Vol 70 (a1) ◽  
pp. C988-C988
Author(s):  
Sergey Arkhipov ◽  
Boris Zakharov ◽  
Elena Boldyreva
Keyword(s):  
High Pressure ◽  
Ascorbic Acid ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Crystal Engineering ◽  
Mixed Crystals ◽  
Study Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range

"Experiments for studying crystalline materials under extreme conditions are a powerful tool for investigating ""structure-property"" relationships. They also give information on the behavior of hydrogen bonds and are important both for materials science and crystal engineering. In addition, many processes in the living organisms are also related to mechanical stress. One of the most interesting tasks is to identify factors which influence the stability of a structure, or a part of the structure, at high pressure. Experiments on the systematic study of compounds in a wide range of pressures allow us to accumulate data that can be used to solve this problem. For a more complete picture, the mixed crystals of the selected compound are studied. Investigation of mixed crystals and cocrystals of interest can be compared with the crystals of individual compounds. We have chosen the structure of L-serine - L-ascorbic acid to be compared with those of L-serine and L-ascorbic acids for such a study. Phase transitions were previously reported to be induced by increasing pressure in both L-serine [1] and L-ascorbic acid [2]; moreover, the structure of L-serine was followed at multiple pressures by single-crystal and powder X-ray diffraction[3]. L-serine – L-ascorbic acid co-crystal was studied in the pressure range 0-5.4 GPa (at multiple points at every 0.5-0.7 GPa) by single-crystal X-ray diffraction and Raman spectroscopy. A phase transition has been detected and some rearrangement in the network of hydrogen bonds was observed. The high pressure data were compared with those for the individual structures of the L-serine and L-ascorbic acid. This work was supported by RFBR (grants 12–03-31541, 14-03-31866, 13-03-92704, 14-03-00902 ), Ministry of Science and Education of Russia and Russian Academy of Sciences."

scholarly journals Redetermination of Dy3Ni from single-crystal X-ray data

2013 ◽  
Vol 69 (11) ◽  
pp. i80-i80
Author(s):  
Volodymyr Levytskyy ◽  
Volodymyr Babizhetskyy ◽  
Bohdan Kotur ◽  
Volodymyr Smetana
Keyword(s):  
Single Crystal ◽  
Structure Type ◽  
Site Symmetry ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wyckoff Position ◽  
Tricapped Trigonal Prism ◽  
Anisotropic Displacement Parameters

The classification of the title compound, tridysprosium nickel, into the Fe3C (or Al3Ni) structure type has been deduced from powder X-ray diffraction data with lattice parameters reported in a previous study [Lemaire & Paccard (1967).Bull. Soc. Fr. Mineral. Cristallogr.40, 311–315]. The current re-investigation of Dy3Ni based on single-crystal X-ray data revealed atomic positional parameters and anisotropic displacement parameters with high precision. The asymmetric unit consists of two Dy and one Ni atoms. One Dy atom has site symmetry .m. (Wyckoff position 4c) and is surrounded by twelve Dy and three Ni atoms. The other Dy atom (site symmetry 1, 8d) has eleven Dy and three Ni atoms as neighbours, forming a distorted Frank–Kasper polyhedron. The coordination polyhedron of the Ni atom (.m., 4c) is a tricapped trigonal prism formed by nine Dy atoms.

Fehlende Glieder bekannter Reihen: Die Oxoferrate(III) Rb8[Fe2O7], Rb6[Fe2O6] und K4[Fe2O5] / Missing Links in Known Series: The Oxoferrates(III) Rb8[Fe2O7], Rb6[Fe2O6], and K4[Fe2O5]

2005 ◽  
Vol 60 (7) ◽  
pp. 732-740 ◽  
Author(s):  
Gero Frisch ◽  
Caroline Röhr
Keyword(s):  
Single Crystal ◽  
Structure Type ◽  
Potassium Ferrate ◽  
X Ray Diffraction ◽  
Marked Contrast ◽  
Ionic Radii ◽  
Space Group ◽  
X Ray ◽  
Type Space ◽  
Alkaline Cations

The title compounds were synthesized at temperatures between 775 and 1175 K from (mostly stoichiometric) mixtures of Fe2O3, elemental rubidium or potassium (A) and their hyperoxides AO2. The structures have been determined by single crystal X-ray diffraction. The alkaline rich ferrate(III) Rb8[Fe2O7] (Cs8[Fe2O7] structure type, space group P21/c, a = 696.7, b = 1722.1, c = 692.0 pm, β = 119.40°, Z = 2, R1 = 0.0496) exhibits diferrate anions [Fe2O7]8- composed of two vertexsharing [FeIIIO4] tetrahedra with a linear Fe-O-Fe bridge and nearly ideal 3m symmetry. This is in marked contrast to the Na homologue, where the diferrate anions are decidedly angular. In the series A3[FeO3], the anions in the compounds of the light alkaline cations are chains 1∞[FeO2O2/2]3−, but similar to the isotypic K6[Fe2O6] and to Cs6[Fe2O6] the new ferrate Rb6[Fe2O6] (K6Fe2O6 structure type, space group C2/m, a=741.8(2), b=1148.7(2), c=680.08(12) pm, β =103.65(2)°, Z = 4, R1 = 0.0370) contains isolated binuclear anions [O2FeO2FeO2]6− composed of two edge sharing [FeO4] tetrahedra. The new potassium ferrate of the series A4[Fe2O5], K4[Fe2O5] (space group P21/c, a = 645.91(14), b = 593.69(13), c = 1003.0(2) pm, β = 103.124(4)°, Z = 4, R1 = 0.0355), constitutes a new structure type, but its structure is still closely related to the Na compound, which crystallizes in the isomorphous subgroup P21/n with a doubled a axis. Both compounds are phylloferrates with layers 2∞[Fe2O5]4− consisting of six-membered rings of [FeO4] tetrahedra. In contrast, Rb4[Fe2O5] contains chains of vertex and edge sharing tetrahedra, so that in both series, A3[FeO3] and A4[Fe2O5], the linkedness of the ferrate tetrahedra increases with the ionic radii of the A counterions.

Inversion parameter of the CoGa2O4 spinel determined from single-crystal X-ray data

2006 ◽  
Vol 62 (5) ◽  
pp. i109-i111 ◽  
Author(s):  
Akihiko Nakatsuka ◽  
Yuya Ikeda ◽  
Noriaki Nakayama ◽  
Tadato Mizota
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Diffraction Data ◽  
Spinel Structure ◽  
Room Temperature ◽  
Structural Formula ◽  
X Ray Diffraction ◽  
X Ray ◽  
Octahedral Sites ◽  
Normal Spinel

Single crystals of cobalt digallium tetraoxide, CoGa2O4, have been grown by cooling slowly a 1:1 mixture of CoO and Ga2O3 from 1473 K to room temperature under the presence of a PbF2 flux. The compound crystallizes with the cubic spinel structure (space group Fd\overline{3}m). The occupancy refinement based on single-crystal X-ray diffraction data shows CoGa2O4 to be a largely normal spinel with an inversion parameter of 0.575 (4), resulting in a structural formula of IV(Co0.425Ga0.575)VI[Co0.575Ga1.425]O4, where IV() and VI[] represent the tetrahedral and the octahedral sites, respectively.

Redefinition of thalénite-(Y) and discreditation of fluorthalénite-(Y): A re-investigation of type material from the Österby pegmatite, Dalarna, Sweden, and from additional localities

2015 ◽  
Vol 79 (4) ◽  
pp. 965-983 ◽  
Author(s):  
Radek Škoda ◽  
Jakub Plášil ◽  
Erik Jonsson ◽  
Renata Čopjaková ◽  
Jörgen Langhof ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Single Crystal ◽  
Electron Microprobe ◽  
Structural Parameters ◽  
Type Material ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Wavelength Dispersive Spectroscopy ◽  
X Ray ◽  
International Mineralogical Association

AbstractUsing type material from the Österby pegmatite in Dalarna, Sweden, the chemical composition and structural parameters of thalénite-(Y) [ideally Y3Si3O10(OH)] were examined by wavelength dispersive spectroscopy electron microprobe (WDS EMP) analysis and single-crystal X-ray diffraction. High contrast back-scatter electron images of the Österby material show at least two generations of thalénite-(Y). The formula of the primary thalénite-(Y) normalized to 11 anions is (Y2.58Dy0.11Yb0.09Gd0.06Er0.06Ho0.02Sm0.02Tb0.02Lu0.02Nd0.01Tm0.01)Σ3.00Si3.01O10F0.97OH0.03. The secondary thalénite-(Y), replacing the primary material, is weakly enhanced in Y and depleted in the lightest and the heaviest rare-earth elements, yielding the formula (Y2.63Dy0.12Yb0.06Gd0.06Er0.05Ho0.02Sm0.02Tb0.02Tm0.01Nd0.01Lu0.01)Σ3.00Si3.01O10F0.98OH0.02. Structural data for thalénite-(Y) from Österby clearly indicate the monoclinic space group P21/n, with a = 7.3464(4), b = 11.1726(5), c = 10.4180(5) Å, β = 97.318(4)°, V = 848.13(7) Å3, Z = 4, which is consistent with previous investigations. The structure was refined from single-crystal X-ray diffraction data to R1 = 0.0371 for 1503 unique observed reflections, and the final chemical composition obtained from the refinement, (Y2.64Dy0.36)Σ3.00F0.987[Si3O10], Z = 4, is in good agreement with the empirical formula resulting from electron microprobe (EMP) analysis. Both techniques reveal a strong dominance of F over OH, which means that the type material actually corresponds to the fluorine analogue. Moreover, new EMP analyses of samples of thalénite-(Y) from an additional seven localities (Åskagen and Reunavare in Sweden; White Cloud and Snow Flake in Colorado, USA; the Guy Hazel claim in Arizona, USA; Suishoyama and Souri in Japan) clearly show the prevalence of F over OH as well. Based on these observations, the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association has recommended a redefinition of the chemical composition of thalénite-(Y) to represent the F-dominant species with the ideal formula Y3Si3O10F, as it has historical priority. Consequently, the later described fluorthalénite-(Y) has to be discredited.

Crystal chemistry of K-rich nepheline in nephelinite from Hamada, Shimane Prefecture, Japan

2018 ◽  
Vol 83 (02) ◽  
pp. 239-247 ◽  
Author(s):  
Maki Hamada ◽  
Masahide Akasaka ◽  
Hiroaki Ohfuji
Keyword(s):  
Single Crystal ◽  
Diffraction Data ◽  
Structural Formula ◽  
Single Crystal Sample ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
Crystal Sample ◽  
X Ray ◽  
Incommensurate Structure ◽  
Absolute Structure

AbstractK-rich nepheline with a structural formula of A2B6T14T24T34T44O32 (Z = 1) within melilite–olivine nephelinite from Hamada, Shimane Prefecture, Japan, was investigated to clarify its crystal structure and to determine cation distributions in the A and B structural positions of structural channels and tetrahedral T1–T4 sites. The chemical formula of a single-crystal sample was (Na5.437K2.248Mg0.034Ca0.031)Σ7.750(Si8.332Al7.445Fe3+0.158Ti0.009Cr0.005)Σ15.949O32, which results in 65.2, 27.8, 2.1, 3.2 and 1.6 mol.% NaAlSiO4, KAlSiO4, NaFe3+SiO4, □Si2O4 and □0.5(Ca,Mg)0.5AlSiO4 end-member components, respectively, where □ is a vacancy. X-ray diffraction data of a single crystal with dimensions of 0.28 mm × 0.15 mm × 0.05 mm measured at 296 K indicate the space group P63. In the structural refinement, the R1 factor was reduced to 3.69% by taking twinning by merohedry into the refinement. The refinement accounted for 77.7% of the absolute structure and 22.3% of the a and b axes reversed absolute structure. The atomic populations determined in the A and B positions were 1.834 K + 0.166 □ and 5.705 Na + 0.198 K + 0.031 Ca + 0.034 Mg, respectively, implying the substitution of K for Na in the B position. The a and c dimensions are a = 10.0270(3) and c = 8.4027(3) Å. The average <A–O> and <B–O> distances are 3.009 and 2.65 Å, respectively. The substitution of K for Na in the B channel results in increased volume and bond-length distortion of the BO8 polyhedra, which then reduces distortion of the AO9 polyhedra. The average T–O distances indicate that the T1 and T4 sites are essentially filled with Al, whereas the T2 and T3 are filled with Si. Despite the deviation of the O1 oxygen from the triad axis and the combination of K+ ions and vacancies in the hexagonal channels, an incommensurate structure was not observed in the X-ray diffraction data or using the electron diffraction technique.

Electron Microscopy of Shock Loaded Polycrystalline Beryllium

1974 ◽  
Vol 32 ◽  
pp. 506-507 ◽  
Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens
Keyword(s):  
Electron Microscopy ◽  
Wave Propagation ◽  
Structural Change ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Shock Loading ◽  
Slip Systems ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.

Crystal structure of an inclusion complex between chiral monoaza-15-crown-5 and S(–)-1-phenyl-ethyl ammonium percholorate

2003 ◽  
Vol 218 (5) ◽  
Author(s):  
Süheyla Özbey ◽  
F. B. Kaynak ◽  
M. Toğrul ◽  
N. Demirel ◽  
H. Hoşgören
Keyword(s):  
Crystal Structure ◽  
Inclusion Complex ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
New Type

AbstractA new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group

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