Na-dominant (at the M2 site) eudialyte analogue: crystal structure and indicatory significance

Minerals of the eudialyte group from ultra-agpaitic associations are often characterized by high contents (up to the dominance) of sodium at the M2 site, which is populated with iron in eudialyte. The features of blocky isomorphism with the replacement of IVFe2+ by IVNa and VNa at the M2 micro-region are discussed. Using the methods of electron probe microanalysis, X-ray diffraction and IR spectroscopy, a potentially new mineral, M2Na-dominant analogue of eudialyte from the Ilimaussaq alkaline massif (Greenland), was investigated. Its crystal structure was refined to R = 5.6 % in the anisotropic approximation of atomic displacements using 1095 independent reflections with F > 3(F). The unit-cell parameters are: a = 14.208(1), c = 30.438(1) Å, V = 5321(1) Å3; the space group is R-3m. The idealized formula of the mineral is (Z = 3): (Na,H3O)15Ca6Zr3[Na2Fe][Si26O72](OH)2Cl∙2H2O.

Download Full-text

Crystal Structure Refinements of Four Monazite Samples from Different Localities

Minerals ◽

10.3390/min10111028 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1028 ◽

Cited By ~ 1

Author(s):

M. Mashrur Zaman ◽

Sytle M. Antao

Keyword(s):

Crystal Structure ◽

Electron Probe ◽

Unit Cell Volume ◽

Unit Cell ◽

X Ray Diffraction ◽

Unit Cell Parameters ◽

X Ray ◽

Cell Parameters ◽

Large Unit Cell ◽

A Site

This study investigates the crystal chemistry of monazite (APO4, where A = Lanthanides = Ln, as well as Y, Th, U, Ca, and Pb) based on four samples from different localities using single-crystal X-ray diffraction and electron-probe microanalysis. The crystal structure of all four samples are well refined, as indicated by their refinement statistics. Relatively large unit-cell parameters (a = 6.7640(5), b = 6.9850(4), c = 6.4500(3) Å, β = 103.584(2)°, and V = 296.22(3) Å3) are obtained for a detrital monazite-Ce from Cox’s Bazar, Bangladesh. Sm-rich monazite from Gunnison County, Colorado, USA, has smaller unit-cell parameters (a = 6.7010(4), b = 6.9080(4), c = 6.4300(4) Å, β = 103.817(3)°, and V = 289.04(3) Å3). The a, b, and c unit-cell parameters vary linearly with the unit-cell volume, V. The change in the a parameter is large (0.2 Å) and is related to the type of cations occupying the A site. The average <A-O> distances vary linearly with V, whereas the average <P-O> distances are nearly constant because the PO4 group is a rigid tetrahedron.

Download Full-text

Crystal structure and indicatopy significance of odikhinchaite from the Khibiny alkaline complex

Vestnik of Geosciences ◽

10.19110/geov.2021.4.1 ◽

2021 ◽

Vol 4 ◽

pp. 3-9

Author(s):

R. K. Rastsvetaeva ◽

◽

N. V. Chukanov ◽

D. V. Lisitsin ◽

M. V. Voronin ◽

...

Keyword(s):

Crystal Structure ◽

Solid Solution Series ◽

X Ray Diffraction ◽

Alkaline Complex ◽

Unit Cell Parameters ◽

X Ray ◽

Cell Parameters ◽

Atomic Displacements ◽

Fe Content ◽

Simplified Formula

Odikhinchaite, a Sr-Mn-Nb-CO3-dominant eudialyte-group mineral from the Khibiny alkaline complex has been investigated using the methods of electron probe microanalysis, X-ray diffraction, infrared and Mössbauer spectroscopy. The crystal structure was refined to R = 3.4 % in the anisotropic approximation of atomic displacements using 3815 independent reflections with F > 3(F). The unit-cell parameters are: a = 14.2709(1), c = 30.023(1) Å, V = 5295.33(7) Å3; the space group is R3m. The simplified formula of the mineral is (Z = 3): Na11Sr3(Mn2+,Fe2+,Fe3+)Ca6Zr3Nb[Si25O72(OH)](CO3)Cl(OH,O)4. The studied sample is the second find of this rare mineral worldwide, represented by a variety with high Fe content in the M2 micro-region, belonging to the taseqite — odikhinchaite solid-solution series. The significance of odikhinchaite as an indicator of a stage corresponding to maximum Sr activity in specific ultraagpaitic pegmatites is discussed.

Download Full-text

First find of a potentially new mineral, Na-dominant at M 2-site eudialyte analogue: crystal structure and significance as a marker of ultraagpaitic environment

Vestnik of Geosciences ◽

10.19110/geov.2021.1.2 ◽

2021 ◽

pp. 14-20

Author(s):

R. K. Rastsvetaeva ◽

N. V. Chukanov ◽

D. V. Lisitsin ◽

K. V. Van ◽

K. A. Viktorova

Keyword(s):

Crystal Structure ◽

Vertex Polyhedron ◽

New Mineral ◽

X Ray Diffraction ◽

Alkaline Complex ◽

Alkaline Pluton ◽

Cell Parameters ◽

Atomic Displacements ◽

Alkaline Massif ◽

Hydrated Sample

A potentially new mineral, M2Na-dominant analogue of eudialyte from the Khibiny alkaline massif, was investigated using the methods of electron probe microanalysis, X-ray diffraction, and IR spectroscopy. The crystal structure was refined to R = 5.7% in the anisotropic approximation of atomic displacements using 2577 independent reflections with F > 3(F). The unit-cell parameters are: a = 14.277(1), c = 30.400(1) Å, V = 5328.7(1) Å3; the space group is R-3m. The idealized formula of the mineral is (Z = 3): Na14Ca6Zr3[Na2(Fe,Mn)][Si26O72](OH)2(H2O1.0Cl0.6S2-0.5)(OH,H2O)2.5. Distribution of cations in the M2 micro-region is established: Fe in the flat-square coordination, Mn in the square pyramid and Na in the seven-vertex polyhedron. A comparative analysis of crystal chemical features of eudialyte М2Na-analogue samples from the Khibiny-Lovozero alkaline complex and Ilimaussaq alkaline pluton, Greenland is given. The mechanism of blocky isomorphism with the replacement of IVFe2+ with VIINa in the M2 micro-region is discussed. IR spectra of the М2Na-dominant eudialyte analogue are given: essentially hydrated sample (Na,H3O,H2O)15Ca6Zr3[Na2Fe][Si26O72](OH)2Cl∙2H2O from Ilimaussaq, less hydrated М2Zr-bearing sample (Na,H3O)13(Ca4Mn2)Zr3(Na2Zr)[Si26O72](OH)2Cl∙H2O from Lovozero and low-hydrated sample Na14Ca6Zr3[Na2(Fe,Mn)][Si26O72](OH)2Cl(OH,H2O)3 from Khibiny studied in this work.

Download Full-text

Tavagnascoite, Bi4O4(SO4)(OH)2, a new oxyhydroxy bismuth sulfate related to klebelsbergite

Mineralogical Magazine ◽

10.1180/minmag.2016.080.010 ◽

2016 ◽

Vol 80 (4) ◽

pp. 647-657 ◽

Cited By ~ 1

Author(s):

Luca Bindi ◽

Cristian Biagioni ◽

Bruno Martini ◽

Adrio Salvetti ◽

Giovanni Dalla Fontana ◽

...

Keyword(s):

Crystal Structure ◽

Hydrogen Bonds ◽

New Mineral ◽

Chemical Formula ◽

X Ray Diffraction ◽

Unit Cell Parameters ◽

Rounding Errors ◽

X Ray ◽

Cell Parameters ◽

Ore District

AbstractThe new mineral tavagnascoite, Bi4O4(SO4)(OH)2, was discovered in the Pb-Bi-Zn-As-Fe-Cu ore district of Tavagnasco, Turin, Piedmont, Italy. It occurs as blocky, colourless crystals, up to 40 μm in size, with a silky lustre. In the specimen studied, tavagnascoite is associated with other uncharacterized secondary Bi-minerals originating from the alteration of a bismuthinite ± Bi-sulfosalt assemblage. Electron microprobe analyses gave (average of three spot analyses, wt.%) Bi2O385.32, Sb2O30.58, PbO 2.18, SO38.46, H2Ocalc1.77, sum 98.31. On the basis of 10 O apfu, the chemical formula is (Bi3.74Pb0.10Sb0.04)∑ = 3.88O3.68(SO4)1.08(OH)2, with rounding errors. Main calculated diffraction lines are [din Å (relative intensity)hkl] 6.39 (29) 012, 4.95 (19) 111,4.019(32)121,3.604(28)014 and 3.213(100)123. Unit-cell parameters area= 5.831(1),b= 11.925(2),c= 15.123(1) Å,V= 1051.6(3) Å3, Z = 4, space groupPca21. The crystal structure was solved and refined from single-crystal X-ray diffraction data toR1= 0.037 on the basis of 1269 observed reflections. It consists of Bi–O polyhedra and SO4tetrahedra. Bismuth polyhedra are connected each to other to form Bi–O sheets parallel to (001). Successive sheets are linked together by SO4groups and hydrogen bonds. Tavagnascoite is the Bi-analogue of klebelsbergite, Sb4O4(SO4)(OH)2, and it is the fifth natural known bismuth sulfate without additional cations. The mineral and its name have been approved by the IMA CNMNC (2014-099).

Download Full-text

The mineralogy of the historical Mochalin Log REE deposit, South Urals, Russia. Part III. Percleveite-(La), La2Si2O7, a new REE disilicate mineral

Mineralogical Magazine ◽

10.1180/mgm.2020.81 ◽

2020 ◽

pp. 1-8

Author(s):

Anatoly V. Kasatkin ◽

Natalia V. Zubkova ◽

Igor V. Pekov ◽

Nikita V. Chukanov ◽

Radek Škoda ◽

...

Keyword(s):

Crystal Structure ◽

New Mineral ◽

South Urals ◽

X Ray Diffraction ◽

Chelyabinsk Oblast ◽

Unit Cell Parameters ◽

X Ray ◽

Cell Parameters ◽

Light Yellow ◽

Mohs Hardness

Abstract The new mineral percleveite-(La) (IMA2019–037), ideally La2Si2O7, was found in polymineralic nodules of the Mochalin Log REE deposit, Chelyabinsk Oblast, South Urals, Russia. It is associated with allanite-(Ce), allanite-(La), bastnäsite-(Ce), bastnäsite-(La), ferriallanite-(Ce), ferriallanite-(La), ferriperbøeite-(Ce), ferriperbøeite-(La), fluorbritholite-(Ce), hydroxylbastnäsite-(Ce), perbøeite-(Ce), perbøeite-(La), törnebohmite-(Ce) and törnebohmite-(La). Percleveite-(La) occurs as isolated anhedral grains commonly up to 0.2 mm × 0.4 mm and very rarely up to 1 mm × 1 mm. The new mineral is transparent with greasy lustre. The mineral is very pale yellow to colourless in thin fragments to light yellow in aggregates. It is brittle, with imperfect {001} cleavage and an uneven fracture. Mohs’ hardness is ca. 6. Dcalc = 5.094 g cm–3. Under the microscope, percleveite-(La) is non-pleochroic, optically uniaxial (+), ω = 1.825(10) and ɛ = 1.835(10). The Raman spectrum is given. Chemical data (wt.%, electron-microprobe) are: La2O3 36.80, Ce2O3 31.22, Pr2O3 1.57, Nd2O3 2.96, SiO2 26.73, total 99.28. The empirical formula based on 7 O apfu is (La1.02Ce0.86Nd0.08Pr0.04)Σ2.00Si2.00O7. Percleveite-(La) is tetragonal, P41; the unit-cell parameters are: a = 6.8482(3), c = 24.8550(13) Å, V = 1165.64(11) Å3 and Z = 8. The strongest reflections in the powder X-ray diffraction pattern [d, Å(I)(hkl)] are: 4.194(18)(113), 3.564(16)(106), 3.349(16)(201,202), 3.157(100)(203,116,008), 3.043(22)(211), 2.934(39)(122), 2.893(29)(213) and 2.864(21)(117). The crystal structure of percleveite-(La) is solved from the single-crystal X-ray diffraction data [R = 0.0617 for 2831 unique reflections with I > 2σ(I)]. The new mineral is named as an analogue of percleveite-(Ce) with La predominance over the rare-earth elements.

Download Full-text

X-ray powder diffraction data of LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites

Powder Diffraction ◽

10.1017/s0885715620000767 ◽

2021 ◽

pp. 1-6

Author(s):

Mariana M. V. M. Souza ◽

Alex Maza ◽

Pablo V. Tuza

Keyword(s):

Crystal Structure ◽

Rietveld Method ◽

Pechini Method ◽

Powder Diffraction Data ◽

X Ray Diffraction ◽

Unit Cell Parameters ◽

X Ray ◽

Cell Parameters ◽

Modified Pechini Method ◽

Scanning Electron

In the present work, LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites were synthesized by the modified Pechini method. These materials were characterized using X-ray fluorescence, scanning electron microscopy, and powder X-ray diffraction coupled to the Rietveld method. The crystal structure of these materials is orthorhombic, with space group Pbnm (No 62). The unit-cell parameters are a = 5.535(5) Å, b = 5.527(3) Å, c = 7.819(7) Å, V = 239.2(3) Å3, for the LaNi0.5Ti0.45Co0.05O3, a = 5.538(6) Å, b = 5.528(4) Å, c = 7.825(10) Å, V = 239.5(4) Å3, for the LaNi0.45Co0.05Ti0.5O3, and a = 5.540(2) Å, b = 5.5334(15) Å, c = 7.834(3) Å, V = 240.2(1) Å3, for the LaNi0.5Ti0.5O3.

Download Full-text

Refinement of the crystal structure of sieleckiite and revision of its symmetry

Mineralogical Magazine ◽

10.1180/minmag.2016.080.143 ◽

2017 ◽

Vol 81 (4) ◽

pp. 917-922

Author(s):

Peter Elliott

Keyword(s):

Crystal Structure ◽

Synchrotron Radiation ◽

Single Crystal ◽

Diffraction Data ◽

X Ray Diffraction ◽

Aluminium Phosphate ◽

Unit Cell Parameters ◽

X Ray ◽

Cell Parameters ◽

Phosphate Mineral

AbstractThe crystal structure of the copper aluminium phosphate mineral sieleckiite, Cu3Al4(PO4)2 (OH)12·2H2O, from the Mt Oxide copper mine, Queensland, Australia was solved from single-crystal X-ray diffraction data utilizing synchrotron radiation. Sieleckiite has monoclinic rather than triclinic symmetry as previously reported and is space group C2/m with unit-cell parameters a = 11.711(2), b = 6.9233(14), c = 9.828(2) Å, β = 92.88(3)°, V = 795.8(3) Å3and Z = 2. The crystal structure, which has been refined to R1 = 0.0456 on the basis of 1186 unique reflections with Fo > 4σF, is a framework of corner-, edge- and face- sharing Cu and Al octahedra and PO4 tetrahedra.

Download Full-text

Synthesis and crystal structure of (Ag,Pd)22Se6

Powder Diffraction ◽

10.1017/s0885715612000929 ◽

2013 ◽

Vol 28 (1) ◽

pp. 13-17 ◽

Cited By ~ 1

Author(s):

F. Laufek ◽

A. Vymazalová ◽

D.A. Chareev ◽

A.V. Kristavchuk ◽

J. Drahokoupil ◽

...

Keyword(s):

Crystal Structure ◽

Diffraction Data ◽

Glass Tube ◽

Structure Type ◽

X Ray Diffraction ◽

Unit Cell Parameters ◽

Synthesis And Crystal Structure ◽

X Ray ◽

Cell Parameters ◽

Silica Glass Tube

The (Ag,Pd)22Se6 phase was synthesized from individual elements by silica glass tube technique and structurally characterized from powder X-ray diffraction data. The (Ag,Pd)22Se6 phase crystallizes in Fm$\overline3$m symmetry, unit-cell parameters: a = 12.3169(2) Å, V = 1862.55(5) Å3, Z = 4, and Dc = 10.01 g/cm3. The crystal structure of the (Ag,Pd)22Se6 phase represents a stuffed 3a.3a.3a superstructure of the Pd structure (fcc), where only 4 from 108 available octahedral holes are occupied. Its crystal structure is related to the Cr23C6 structure type.

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

Expression, purification, crystallization and X-ray diffraction studies of the molecular chaperone prefoldin fromHomo sapiens

Acta Crystallographica Section F Structural Biology Communications ◽

10.1107/s2053230x15013990 ◽

2015 ◽

Vol 71 (9) ◽

pp. 1189-1193 ◽

Cited By ~ 3

Author(s):

Yoshiki Aikawa ◽

Hiroshi Kida ◽

Yuichi Nishitani ◽

Kunio Miki

Keyword(s):

Crystal Structure ◽

Protein Folding ◽

Diffraction Data ◽

Molecular Chaperone ◽

X Ray Diffraction ◽

Unit Cell Parameters ◽

X Ray ◽

Cell Parameters ◽

Native Proteins ◽

Group Ii Chaperonin

Proper protein folding is an essential process for all organisms. Prefoldin (PFD) is a molecular chaperone that assists protein folding by delivering non-native proteins to group II chaperonin. A heterohexamer of eukaryotic PFD has been shown to specifically recognize and deliver non-native actin and tubulin to chaperonin-containing TCP-1 (CCT), but the mechanism of specific recognition is still unclear. To determine its crystal structure, recombinant human PFD was reconstituted, purified and crystallized. X-ray diffraction data were collected to 4.7 Å resolution. The crystals belonged to space groupP21212, with unit-cell parametersa= 123.2,b= 152.4,c= 105.9 Å.

Download Full-text