Aravaite, Ba2Ca18(SiO4)6(PO4)3(CO3)F3O: modular structure and disorder of a new mineral with single and triple antiperovskite layers

The crystal structure of the new mineral aravaite Ba2Ca18(SiO4)6(PO4)3(CO3)F3O [R{\bar 3}m, a = 7.12550 (11), c = 66.2902 (13) Å, V = 2914.81 (8) Å3, Z = 3] was solved from single-crystal diffraction data, collected using synchrotron radiation at the X06DA beamline of the Swiss Light Source. The unit cell of this modular mineral contains six layers of {Ba(PO4)1.5(CO3)0.5}3.5− (T-layer), three triple antiperovskite layers (tAP) {(F2OCa12)(SiO4)4}4+, and three single antiperovskite layers (sAP) {(FCa6)(SiO4)2}3+. The structure refinement confirms a model with a layer sequence of T–sAP–T–tAP as an average structure of this mineral. However, one-dimensional diffuse scattering observed parallel to c* implies imperfections in the stacking sequence of the average structure. Qualitative modelling of disorder confirms that the alternating sequence of T–sAP and T–tAP blocks is disturbed. The blocks occurring in this new mineral are known from other so-called hexagonal intercalated antiperovskite structures: T–sAP (stracherite and zadovite group), T–tAP (ariegilatite and nabimusaite group).

Download Full-text

Therasiaite, (NH4)3KNa2Fe2+Fe3+(SO4)3Cl5, a new sulfate chloride from La Fossa Crater, Vulcano, Aeolian islands, Italy

Mineralogical Magazine ◽

10.1180/minmag.2014.078.1.14 ◽

2014 ◽

Vol 78 (1) ◽

pp. 203-213 ◽

Cited By ~ 5

Author(s):

F. Demartin ◽

C. Castellano ◽

I. Campostrini

Keyword(s):

Structure Refinement ◽

New Mineral ◽

Monoclinic Space Group ◽

Ammonium Ions ◽

Single Crystal Diffraction ◽

Sulfate Ions ◽

Aeolian Islands ◽

Distorted Octahedral ◽

Cl Atoms ◽

Fossa Crater

AbstractThe new mineral therasiaite, ideally (NH4)3KNa2Fe2+Fe3+(SO4)3Cl5, was found in a mediumtemperature (∼250°C) intracrater active fumarole at La Fossa crater, Vulcano, Aeolian Islands, Sicily, Italy. It occurs on a pyroclastic breccia as brown to dark brown equant to short prismatic crystals up to 0.1 mm in length, in association with salammoniac, kremersite and adranosite. The mineral is monoclinic, space group: Cc (no. 9) with a = 18.284(4), b = 12.073(2), c = 9.535(2) Å, β = 108.10(3)°, V = 2000.6(7) Å3 and Z = 4. The six strongest reflections in the X-ray powder diffraction pattern are: [dobs in Å(I)(hkl)] 2.812(100)(23), 2.664(77)(13), 3.297(28)(33), 3.208(14)(2), 3.008(12)(040), 2.942(11)(331). The empirical formula (based on 17 anions per formula unit (p.f.u.)) is (NH4)2.68K1.32Na2.04Fe1.76Al0.12Mn0.12S2.98O11.95Cl5.05. The measured density is 2.41(1) g cm−3, dcalc = 2.395 g cm−3. The mineral is biaxial (−) with α= 1.585(3) β = 1.615(3) and γ = 1.630(3) (white light). Using single-crystal diffraction data, the structure was refined to a final R(F) = 0.0240 for 5574 independent observed reflections [I > 2σ(I)]. The structure of therasiaite displays a novel topology and contains two independent, distorted octahedral Fe sites, with the Fe atoms in oxidation state 3+ and 2+, respectively, each surrounded by three Cl atoms and three oxygens of the sulfate ions. The Fe octahedra and the three independent sulfate anions are connected to form chains running along [001]. Voids between the chains are occupied by three independent ammonium ions (partially replaced by K+), one K+ and two Na+ ions. The formula resulting from the structure refinement is [(NH4)2.25K0.75]KNa2Fe2(SO4)3Cl5.

Download Full-text

Arrheniusite-(Ce), CaMg[(Ce7Y3)Ca5](SiO4)3(Si3B3O18)(AsO4)(BO3)F11, a New Member of the Vicanite Group, from the Östanmossa Mine, Norberg, Sweden

The Canadian Mineralogist ◽

10.3749/canmin.2000045 ◽

2021 ◽

Author(s):

Dan Holtstam ◽

Luca Bindi ◽

Paola Bonazzi ◽

Hans-Jürgen Förster ◽

Ulf B. Andersson

Keyword(s):

Structure Refinement ◽

New Mineral ◽

X Ray Diffraction ◽

Unit Cell Parameters ◽

Calculated Density ◽

Epma Data ◽

X Ray ◽

Cell Parameters ◽

Greenish Yellow ◽

The Ideal

ABSTRACT Arrheniusite-(Ce) is a new mineral (IMA 2019-086) from the Östanmossa mine, one of the Bastnäs-type deposits in the Bergslagen ore region, Sweden. It occurs in a metasomatic F-rich skarn, associated with dolomite, tremolite, talc, magnetite, calcite, pyrite, dollaseite-(Ce), parisite-(Ce), bastnäsite-(Ce), fluorbritholite-(Ce), and gadolinite-(Nd). Arrheniusite-(Ce) forms anhedral, greenish-yellow translucent grains, exceptionally up to 0.8 mm in diameter. It is optically uniaxial (–), with ω = 1.750(5), ε = 1.725(5), and non-pleochroic in thin section. The calculated density is 4.78(1) g/cm3. Arrheniusite-(Ce) is trigonal, space group R3m, with unit-cell parameters a = 10.8082(3) Å, c = 27.5196(9) Å, and V = 2784.07(14) Å3 for Z = 3. The crystal structure was refined from X-ray diffraction data to R1 = 3.85% for 2286 observed reflections [Fo > 4σ(Fo)]. The empirical formula for the fragment used for the structural study, based on EPMA data and results from the structure refinement, is: (Ca0.65As3+0.35)Σ1(Mg0.57Fe2+0.30As5+0.10Al0.03)Σ1[(Ce2.24Nd2.13La0.86Gd0.74Sm0.71Pr0.37)Σ7.05(Y2.76Dy0.26Er0.11Tb0.08Tm0.01Ho0.04Yb0.01)Σ3.27Ca4.14]Σ14.46(SiO4)3[(Si3.26B2.74)Σ6O17.31F0.69][(As5+0.65Si0.22P0.13)Σ1O4](B0.77O3)F11; the ideal formula obtained is CaMg[(Ce7Y3)Ca5](SiO4)3(Si3B3O18)(AsO4)(BO3)F11. Arrheniusite-(Ce) belongs to the vicanite group of minerals and is distinct from other isostructural members mainly by having a Mg-dominant, octahedrally coordinated site (M6); it can be considered a Mg-As analog to hundholmenite-(Y). The threefold coordinated T5 site is partly occupied by B, like in laptevite-(Ce) and vicanite-(Ce). The mineral name honors C.A. Arrhenius (1757–1824), a Swedish officer and chemist, who first discovered gadolinite-(Y) from the famous Ytterby pegmatite quarry.

Download Full-text

Farneseite, a new mineral of the cancrinite - sodalite group with a 14-layer stacking sequence: occurrence and crystal structure

European Journal of Mineralogy ◽

10.1127/0935-1221/2005/0017-0839 ◽

2006 ◽

Vol 17 (6) ◽

pp. 839-846 ◽

Cited By ~ 17

Author(s):

Fernando Cá mara ◽

Fabio Bellatreccia ◽

Giancarlo Della Ventura ◽

Annibale Mottana

Keyword(s):

Crystal Structure ◽

New Mineral ◽

Stacking Sequence ◽

Layer Stacking

Download Full-text

Pushing the limits: determining the average structure in the presence of strong diffuse scattering

Acta Crystallographica Section A Foundations of Crystallography ◽

10.1107/s0108767313096323 ◽

2013 ◽

Vol 69 (a1) ◽

pp. s420-s420 ◽

Cited By ~ 1

Author(s):

Rangana Warshamanage ◽

Anthony Linden ◽

Hans-Beat Bürgi

Keyword(s):

Diffuse Scattering ◽

Average Structure

Download Full-text

Mixed Ca/Sr salt forms of salicylic acid: tuning structure and aqueous solubility

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229617018265 ◽

2018 ◽

Vol 74 (2) ◽

pp. 131-138 ◽

Cited By ~ 1

Author(s):

Pamela Allan ◽

Jean-Baptiste Arlin ◽

Alan R. Kennedy ◽

Aiden Walls

Keyword(s):

Salicylic Acid ◽

Coordination Polymer ◽

Single Crystal ◽

Structural Feature ◽

Structural Changes ◽

Aqueous Solubility ◽

Single Crystal Diffraction ◽

One Dimensional ◽

The One ◽

Salt Forms

Ten isostructural single-crystal diffraction studies of mixed cation Ca/Sr salt forms of the salicylate anion are presented, namely catena-poly[[diaquacalcium(II)/strontium(II)]-bis(μ2-2-hydroxybenzoato)], [Ca1–x Sr x (C7H5O3)2(H2O)2] n , where x = 0, 0.041, 0.083, 0.165, 0.306, 0.529, 0.632, 0.789, 0.835 and 1. The structure of an isostructural Sr/Ba species, namely catena-poly[[diaquastrontium(II)/barium(II)]-bis(μ2-2-hydroxybenzoato)], [Sr0.729Ba0.271(C7H5O3)2(H2O)2], is also described. The Ca/Sr structures form a series where, with increasing Sr content, the unit cell expands in both the crystallographic a and c directions (by 1.80 and 3.18%, respectively), but contracts slightly in the b direction (−0.31%). The largest percentage structural expansion lies parallel to the direction of propagation of the one-dimensional coordination polymer that is the primary structural feature. This structural expansion is thus associated with increased M—O distances. Aqueous solubility measurements show that solubility generally increases with increasing Sr content. Thus, tuning the composition of these mixed counter-ion salt forms leads to systematic structural changes and allows solubility to be tuned to values between those for the pure Ca and Sr species.

Download Full-text

X-ray diffuse scattering as precursor of incommensurate Peierls transitions in one-dimensional organic charge transfer conductors

Zeitschrift für Kristallographie - Crystalline Materials ◽

10.1524/zkri.219.11.711.52440 ◽

2004 ◽

Vol 219 (11) ◽

Cited By ~ 10

Author(s):

Jean-Paul Pouget

Keyword(s):

Charge Transfer ◽

Charge Density Wave ◽

Diffuse Scattering ◽

Lattice Distortion ◽

Density Wave ◽

Periodic Lattice ◽

One Dimensional ◽

X Ray ◽

Charge Transfer Salts ◽

A Charge

AbstractQuasi-one dimensional (1D) conductors of the TTF-TCNQ family of charge transfer salts exhibit a Peierls transition which stabilizes a periodic lattice distortion (PLD), accompanied by a charge density wave (CDW) modulation, with an incommensurate 2

Download Full-text

Roughness replication in neutron supermirrors

Journal of Applied Crystallography ◽

10.1107/s1600576716019385 ◽

2017 ◽

Vol 50 (1) ◽

pp. 184-191 ◽

Cited By ~ 2

Author(s):

Tamás Veres ◽

Szilárd Sajti ◽

László Cser ◽

Szabolcs Bálint ◽

László Bottyán

Keyword(s):

Diffuse Scattering ◽

Interface Roughness ◽

Angle Of Incidence ◽

Bilayer Thickness ◽

Correlation Lengths ◽

Layer Sequence ◽

Out Of Plane ◽

Common Interface ◽

Correlation Parameters ◽

Characteristic Features

Neutron supermirrors (SMs), the major components of neutron optical devices, are depth-graded d-spacing multilayers of several hundreds to several thousands of bilayers. The interface roughness is a major factor in the reflectivity of multilayers. This influence is especially significant if the number of bilayers is large. In this work, the interface roughness and its correlations were studied in DC-sputtered Ni–Ti neutron supermirrors. Detector scans were carried out to observe off-specular neutron scattering in selected regions of the q space from (increasing bilayer thickness) normal- and (decreasing bilayer thickness) reverse-layer-sequence SMs. In-plane and out-of-plane roughness correlations are manifested in diffuse scatter plateaus and peaks which are interpreted in terms of resonant diffuse scattering. Distorted wave Born approximation simulations quantitatively reproduce the characteristic features of the measured detector scans with reasonable roughness correlation parameters, i.e. in-plane and out-of-plane correlation lengths, common interface roughness, and Hurst parameters. The different character of resonant diffuse scattering from normal- and reverse-layer-sequence SMs is qualitatively explained and systematized using quasi-kinematical considerations in terms of material and SM parameters. The total off-specular intensity of the supermirrors was found to be non-monotonic with respect to the specular reflectivity at the corresponding angle of incidence.

Download Full-text

Bassoite, SrV3O7·4H2O, a new mineral from Molinello mine, Val Graveglia, eastern Liguria, Italy

Mineralogical Magazine ◽

10.1180/minmag.2011.075.5.2677 ◽

2011 ◽

Vol 75 (5) ◽

pp. 2677-2686 ◽

Cited By ~ 3

Author(s):

L. Bindi ◽

C. Carbone ◽

R. Cabella ◽

G. Lucchetti

Keyword(s):

Structure Refinement ◽

Full Professor ◽

New Mineral ◽

Monoclinic Space Group ◽

Calculated Density ◽

X Ray ◽

Cell Parameters ◽

Mohs Hardness ◽

Dark Green ◽

The University

AbstractBassoite, ideally SrV3O7·4H2O, is a new mineral from the Molinello manganese mine, Val Graveglia. eastern Liguria, northern Apennines, Italy. It occurs as black euhedral to subhedral grains up to 400 urn across, closely associated with rhodonite, quartz and braunite. Bassoite is opaque with a sub-metallic lustre and a black streak. It is brittle and neither fracture nor cleavage was observed; the Vickers micro-hardness (VHN100) is 150 kg/mm (range 142—165; corresponding to a Mohs hardness of 4—41/2). The calculated density is 2.940 g/cm3 (on the basis of the empirical formula and X-ray single-crystal data). Bassoite is weakly bireflectant and very weakly pleochroic from grey to a dark green. Internal reflections are absent. The mineral is anisotropic, without characteristic rotation tints. Reflectance percentages (Rmin and Rmax) for the four standard COM wavelengths are 18.5%, 19.0% (471.1 nm); 17.2%, 17.8% (548.3 nm); 16.8%, 17.5% (586.6 nm) and 16.2%, 16.8% (652.3 nm), respectively.Bassoite is monoclinic, space group P21/m, with unit-cell parameters: a = 5.313(3) Å, b = 10.495(3) Å, c = 8.568(4) Å, β = 91.14(5)°, V= 477.7(4) Å3, a:b:c = 0.506:1:0.816, and Z = 2. The crystal structure was refined to R1 = 0.0209 for 1148 reflections with Fo > 4σ(Fo) and it consists of layers of VO5 pyramids (with vanadium in the tetravalent state) pointing up and down alternately with Sr between the layers (in nine-fold coordination). The nine most intense X-ray powder-diffraction lines [d in Å (I/I0) (hkt)] are: 8.5663 (100) (001); 6.6363 (14) (011); 3.4399 (14) (1̄21); 3.4049 (17) (121); 2.8339 (15) (1̄22); 2.7949 (11) (122); 2.6550 (15) (200); 2.6237 (11) (040) and 1.8666 (15) (240). Electron microprobe analyses produce a chemical formula (Sr0.97Ca0.02Na0.01)V3.00O74H20, on the basis of 2(Sr+Ca+Na) = 1, taking the results of the structure refinement into account. The presence of water molecules was confirmed by micro-Raman spectroscopy. The name honours Riccardo Basso (b. 1947), full professor of Mineralogy and Crystallography at the University of Genova. The new mineral and mineral name have been approved by the Commission on New Minerals, Nomenclature and Classification, IMA (2011-028).

Download Full-text

Imayoshiite, Ca3Al(CO3)[B(OH)4](OH)6·12H2O, a new mineral of the ettringite group from Ise City, Mie Prefecture, Japan

Mineralogical Magazine ◽

10.1180/minmag.2015.079.2.18 ◽

2015 ◽

Vol 79 (2) ◽

pp. 413-423 ◽

Cited By ~ 11

Author(s):

D. Nishio-Hamane ◽

M. Ohnishi ◽

K. Momma ◽

N. Shimobayashi ◽

R. Miyawaki ◽

...

Keyword(s):

Single Crystal ◽

Powder Diffraction ◽

White Light ◽

New Mineral ◽

Structural Refinement ◽

Single Crystal Diffraction ◽

Ettringite Group ◽

Mohs Hardness ◽

White Streak

AbstractImayoshiite, Ca3Al(CO3)[B(OH)4](OH)6·12H2O, occurs in cavities in the altered gabbro xenolith in the sepentinized dunite exposed at Suisho-dani, Ise City, Mie Prefecture, Japan. Imayoshiite is colourless and transparent with a vitreous lustre and its aggregates are white with a silky lustre. Imayoshiite has a white streak. Its Mohs hardness is 2–3. It is brittle, the cleavage is distinct on {100} and the fracture is uneven. The mineral is uniaxial (–) with the indices of refraction ω = 1.497(2) and ε = 1.470(2) in white light. Imayoshiite is hexagonal, P63, a = 11.0264(11), c = 10.6052(16) Å by powder diffraction and a = 11.04592(2), c = 10.61502(19) Å by single-crystal diffraction. The structural refinement converged to R1 = 2.35%. Imayoshiite is the first member of the ettringite group with both CO3 and B(OH)4 anions.

Download Full-text