Crystal structure and Raman spectroscopic studies of OH stretching vibrations in Zn-rich fluor-elbaite

2020 ◽  
Vol 105 (11) ◽  
pp. 1622-1630 ◽  
Author(s):  
Adam Pieczka ◽  
Andreas Ertl ◽  
Bożena Gołębiowska ◽  
Piotr Jeleń ◽  
Jakub Kotowski ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Raman Spectroscopy ◽  
Electron Microprobe ◽  
Integral Intensity ◽  
Structure Refinement ◽  
Gaussian Function ◽  
Raman Shift ◽  
Crystal Chemical ◽  
Site Occupation ◽  
Stretching Vibrations

Abstract Zinc-rich fluor-elbaite from Piława Górna, Poland, was studied by electron microprobe (EPMA), single-crystal X-ray diffraction (SREF), and Raman spectroscopy (RS) to check the possibility of the application of RS to draw crystal-chemical conclusions for Al-rich and Li-bearing tourmalines on basis of the O–H stretching vibrations in the spectral range 3400–3800 cm–1. This tourmaline, forming a thin metasomatic zone around gahnite, features varying compositions with a ZnO content reaching in the studied fragment of 5.70(12) wt%. The crystal structure of this Zn-rich fluor-elbaite [a = 15.921(1), c = 7.127(1) Å] was refined with a R1 value of 1.67%. Its formula was determined on the basis of electron-microprobe and structure refinement as (Na0.84☐0.14Ca0.01)XΣ1.00(Al1.06Li0.84Zn0.69Fe0.322+Mn0.09)YΣ3.00AlZ6(BO3)3(Si6TO18)(OH)3V(F0.65OH0.26O0.09)W. The deconvolution of the O–H stretching vibration bands, performed by fitting of an input model of component bands with Gaussian function shapes for the empirical spectrum, indicates that each of the three maxima assigned for VOH bonded to YAl3+, Y2+, and YLi+ and with the total integral intensity of at least 75% of the total OH content could be resolved into 1 to 3 bands, depending on the X-site occupation (vacancies, Na+, and Ca2+). The deconvolution indicates further that several low intense bands of WO–H modes above a Raman shift of 3600 cm–1, totally reaching ≤25%, are dependent on the occupation of triplets of YYY cations bonded to the hydroxyl. These WO–H modes are also influenced by the X-site occupation. Due to ordering of all octahedral cations (except Al) at the Y site and a complete occupation of the Z site by Al and the V site by OH, it seems possible to evaluate the Li and OH contents in a Al-rich and Li-bearing tourmaline directly from the Raman spectrum. By using the ratio VOHIYAlZAlZAl/(VOHIYZZ + WOHIYYY) as evaluated from RS, corresponding to the ratio YAl/V+WOH in the crystal, the formula of the Zn-rich fluor-elbaite can be calculated as (Na0.85☐0.14Ca0.01)XΣ1.00(Al1.11Y1.112+Li0.78)YΣ3.00AlZ6(BO3)3(Si6O18)(OH)3(F0.65OH0.13O0.22), where Y 2+ = Zn + Fe + Mn. The formula, determined only on basis of EPMA and deconvolution of RS in the O–H stretching bands, corresponds very well (≤1 SD range of EPMA) to the formula determined on basis of EPMA and SREF. This result implicates that the O–H stretching vibrations, measured by Raman spectroscopy, could be applied for Al-rich and Li-bearing tourmalines as a useful tool for providing additional information for determining the crystal-chemical formula. It is also very helpful when crystal structural data are not available.

scholarly journals Asbecasite: crystal structure refinement and crystal chemistry

1993 ◽  
Vol 57 (387) ◽  
pp. 315-322 ◽  
Author(s):  
Michele Sacerdoti ◽  
Gian Carlo Parodi ◽  
Annibale Mottana ◽  
Adriana Maras ◽  
Giancarlo Della Ventura
Keyword(s):  
Crystal Structure ◽  
Crystal Chemistry ◽  
Structure Determination ◽  
Electron Microprobe ◽  
Structure Refinement ◽  
Volcanic Complex ◽  
Crystal Chemical ◽  
Crystal Structure Refinement ◽  
Roman Potassic Province ◽  
Original Crystal

AbstractThe crystal structure of antimonian asbecasite in an ejectum of hypabyssal origin occurring at Tre Croci near Vetralla, Vico volcanic complex, Roman potassic province, Latium, Italy, has been refined to R = 0.042, and is compared to the original crystal structure determination carried out on the Sb-free asbecasite of hydrothermal metamorphic origin from the type-locality, Cherbandung in Binna valley, Monte Leone nappe, Switzerland. New electron microprobe analyses of samples from both localities demonstrate crystal-chemical features that permit distinction between asbecasites from the two occurrences, so far the only known localities for this mineral.

Al analogue of chayesite from a lamproite of Cancarix, SE Spain, and its crystal structure

2020 ◽  
Vol 196 (3) ◽  
pp. 193-198
Author(s):  
Natalia V. Zubkova ◽  
Nikita V. Chukanov ◽  
Christof Schäfer ◽  
Konstantin V. Van ◽  
Igor V. Pekov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Empirical Formula ◽  
Structure Refinement ◽  
Crystal Chemical ◽  
Chemical Formula ◽  
Crystal Chemical Formula ◽  
X Ray Diffraction ◽  
Se Spain ◽  
X Ray

Al analogue of chayesite (with Al > Fe3+) was found in a lamproite from Cancarix, SE Spain. The mineral forms green thick-tabular crystals up to 0.4 mm across in cavities. The empirical formula derived from EMP measurements and calculated on the basis of 17 Mg + Fe + Al + Si apfu is (K0.75 Na0.20 Ca0.11)Mg3.04 Fe0.99 Al1.18 Si11.80 O30. The crystal structure was determined from single crystal X-ray diffraction data ( R = 2.38%). The mineral is hexagonal, space group P 6/ mcc, a = 10.09199(12), c = 14.35079(19) Å, V = 1265.78(3) Å3, Z = 2. Fe is predominantly divalent. Al is mainly distributed between the octahedral A site and the tetrahedral T 2 site. The crystal chemical formula derived from the structure refinement is C (K0.73 Na0.16 Ca0.11)B (Na0.02)4 A(Mg0.42 Al0.29 Fe0.29)2 T 2(Mg0.71 Fe0.16 Al0.13)3 T 1(Si0.985 Al0.015)12 O30.

Vibrational properties of nanoparticles iron oxide by Raman spectroscopy

2020 ◽  
pp. 2150125
Author(s):  
T. A. Darziyeva ◽  
E. Sh. Alekperov ◽  
S. H. Jabarov ◽  
M. N. Mirzayev
Keyword(s):  
Crystal Structure ◽  
Raman Spectroscopy ◽  
Iron Oxide ◽  
Gaussian Function ◽  
High Symmetry ◽  
X Ray Diffraction ◽  
Cubic Crystal ◽  
Cubic Symmetry ◽  
Structure Calculations ◽  
Crystal Structure Calculations

The crystal structure and atomic dynamics of Fe3O4 nanoparticles have been studied. The crystal structure of iron oxide nanoparticles was determined by X-ray diffraction. The analysis showed that the crystal structure of [Formula: see text] 50–100 nm dimensional iron oxide corresponds to a high symmetry cubic crystal structure. Calculations have shown that there are four infrared active, five Raman active and seven hyper-Raman active modes in the space group Fd-3m with cubic symmetry. Four of these modes have been observed using Raman spectroscopy: 213, 271, 380 and 591 cm[Formula: see text]. The vibrational modes are interpreted by Gaussian function. It was found that these vibration modes correspond to the vibration of O–Fe–O bonds and iron-oxygen polyhedra.

The structure of antimonian dussertite and the role of antimony in oxysalt minerals

1999 ◽  
Vol 63 (1) ◽  
pp. 17-26 ◽  
Author(s):  
U. Kolitsch ◽  
P. G. Slade ◽  
E. R. T. Tiekink ◽  
A. Pring
Keyword(s):  
Hydrogen Bonding ◽  
Electron Microprobe ◽  
Structure Refinement ◽  
Bond Valence ◽  
Crystal Chemical ◽  
Coordination Polyhedra ◽  
Space Group ◽  
Bond Lengths ◽  
The Mean

AbstractThe structure of antimonian dussertite, (AsO4)2(OH,H2O)6, has been refined in space group R3̄m with a 7.410(3), c 17.484(4) Å, Z = 3, to R = 3.2 % and Rw = 3.7 % using 377 observed reflections with I ≥ 3 σ(I). The structure is of the alunite-type and consists of sheets of corner-sharing (Fe3+,Sb5+)O6 octahedra parallel to (0001). The substitution of Sb5+ for Fe3+, and not for As5+, is unambiguously demonstrated not only by the structure refinement but also by electron microprobe analyses and crystal-chemical considerations. The icosahedrally coordinated Ba cations occupy cavities between pairs of octahedral sheets and are surrounded by six O atoms from the AsO4 tetrahedra and six O atoms from the (Fe3+,Sb5+)O6 octahedra. The mean bond lengths for the various coordination polyhedra are As-O 1.684(3) Å, (Fe,Sb)-O 2.004(1) Å, and Ba-O 2.872(2) Å. A hydrogen-bonding network is modelled using bond-valence calculations. The dussertite sample investigated is the first member of the crandallite group found to contain substantial Sb.

Fluoronyböite from Jianchang (Su-Lu, China) and nyböite from Nybö (Nordfjord, Norway): a petrological and crystal-chemical comparison of these two high-pressure amphiboles

2003 ◽  
Vol 67 (4) ◽  
pp. 769-782 ◽  
Author(s):  
R. Oberti ◽  
M. Boiocchi ◽  
D. C. Smith
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Structure Refinement ◽  
New Mineral ◽  
Cation Ordering ◽  
Crystal Chemical ◽  
Crystal Structure Refinement ◽  
Mineral Data

AbstractFluoronyböite, ideally NaNa2(Al2Mg3)(Si7Al)O22F2, has been found in the Jianchang eclogite pod, Su-Lu coesite-eclogite province, China. It has been approved as a new mineral by the IMA. Single-crystal structure refinement and electron microprobe analysis were used for characterization: C2/m, with a = 9.666(4), b = 17.799(6), c = 5.311(2) Å, β = 104.10(3)º, V = 886.2(8) Å3, Z = 2, formula: A(Na0.78K0.06)Σ0.84B(Na1.53Ca0.47)Σ2.00C(Fe2+0.89Mg2.55Mn0.01Zn0.01Fe3+0.32Al1.21Ti0.01)Σ5.00T(Si7.14Al0.86)Σ8.00O22X(OH0.84F1.16)Σ2.00.Fluoronyböite formed during UHPM conditions, and is preserved in the retrograded kyanite-bearing eclogite sample DJ102 together with clinopyroxene (Jd70Ae20Di10), garnet (Alm60Prp21Grs17Sps02), and rutile. Lower-pressure minerals are also present (fluoro-alumino-magnesiotaramite, apatite, paragonite), and symplectitic rims were also developed around clinopyroxene crystals. Cation ordering and the structural and physical properties of fluoronyböite are reported and discussed with reference to those of F-free nyböite from the type locality at Nyböin Norway, for which some as yet unpublished mineral data are also reported. Relations between composition and petrogenetic conditions of these rare high-pressure amphiboles are discussed.

scholarly journals The walentaite group and the description of a new member, alcantarillaite, from the Alcantarilla mine, Belalcázar, Córdoba, Andalusia, Spain.

2020 ◽  
Vol 84 (3) ◽  
pp. 412-419
Author(s):  
Ian E. Grey ◽  
Rupert Hochleitner ◽  
Christian Rewitzer ◽  
Alan Riboldi-Tunnicliffe ◽  
Anthony R. Kampf ◽  
...  
Keyword(s):  
Crystal Structure ◽  
White Light ◽  
Electron Microprobe ◽  
Structure Refinement ◽  
Structural Formula ◽  
Lemon Yellow ◽  
Optical Orientation ◽  
Crystal Structure Refinement ◽  
Calculated Density ◽  
Group Members

AbstractThe general structural formula for the walentaite group is [((A1yA1’1–y), A2)(H2O)n][Bx(As2)2–x(As3)M1(M2)2(TO4)2(O,OH)7], based on heteropolyhedral layers of configuration [M1(M2)2(TO4)2(O,OH)6], with surface-coordinated species at the B, As2 and As3 sites, and with interlayer hydrated cation groups centred at the A sites. The group is divided into walentaite and halilsarpite subgroups based on T = P5+ and As5+, respectively. Alcantarillaite, (IMA2019-072), [Fe3+0.5□0.5(H2O)4][CaAs3+2(Fe3+2.5W6+0.5)(AsO4)2O7], is a new member of the walentaite group from the Alcantarilla wolframite mine, Belalcázar, Córdoba, Andalusia, Spain. It occurs most commonly as lemon-yellow fillings together with massive scorodite in fissures and cracks in quartz adjacent to löllingite. It is also found as tiny yellow rosettes lining vugs and as spheroids of ultrathin blades. It is associated with scorodite, pharmacosiderite, ferberite and schneiderhöhnite. Optically it is biaxial (–), with α = 1.703(calc), β = 1.800(5), γ = 1.850(5) and 2V = 68(1)° (white light). Dispersion is r > v, moderate. The optical orientation is X = a, Y = c and Z = b. The calculated density is 3.06 g cm–3. Electron microprobe analyses together with crystal structure refinement results gives the empirical formula [Fe3+0.52□0.48(H2O)4][(Ca0.44K0.11Na0.05Fe2+0.24□0.42)As3+1.83][Fe3+2.54Al0.03W6+0.43)((As0.65P0.35)O4)2O5.86(OH)1.14]. Alcantarillaite is orthorhombic, with an average structure described in Imma, and with a = 24.038(8) Å, b = 7.444(3) Å, c = 10.387(3) Å, V = 1858.6(11) Å3 and Z = 4. The structure (wRobs = 0.078 for 651 reflections to a resolution of 0.91 Å) differs most significantly from other walentaite-group members in having an interlayer A2 site occupied. Square-pyramidal polyhedra centred at the A2 sites form edge-shared dimers, (Fe3+)2O4(H2O)4. The dimers share vertices with TO4 anions in the layers on either side to form 8-sided channels along [010] occupied by H2O molecules.

Magnesio-hornblende from Lüderitz, Namibia: mineral description and crystal chemistry

2018 ◽  
Vol 82 (6) ◽  
pp. 1253-1259
Author(s):  
Roberta Oberti ◽  
Massimo Boiocchi ◽  
Frank C. Hawthorne ◽  
Marco E. Ciriotti
Keyword(s):  
Crystal Structure ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Structure Refinement ◽  
Sand Dunes ◽  
Crystal Structure Refinement ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters

ABSTRACTMagnesio-hornblende (IMA2017-059) has been characterized in a specimen collected in the sand dunes of Lüderitz, Karas Region, Namibia. The empirical formula derived from electron microprobe analysis and single-crystal structure refinement is A(□0.73Na0.22K0.05)Σ1.00B(Ca1.79Fe2+0.10Mg0.04Mn2+0.03Na0.04)Σ2.00C(Mg3.48Fe2+0.97Al0.28Fe3+0.23Cr3+0.01Ti0.03)Σ5.00T(Si7.18Al0.82)Σ8.00O22W[(OH)1.93F0.05Cl0.02]Σ2.00. Magnesio-hornblende is biaxial (–), with α = 1.640(2), β = 1.654(2), γ = 1.666(2) (measured with gel-filtered Na light, λ = 589.9 nm), 2V (meas.) = 82(1)° and 2V (calc.) = 84.9°. The unit-cell parameters are a = 9.8308(7), b = 18.0659(11), c = 5.2968(4) Å, β = 104.771(6)° and V = 909.64 (11) Å3 with Z = 2 and space group C2/m. The strongest eight reflections in the X-ray powder pattern [d values (in Å), I, (hkl)] are: 2.709, 100, (151); 8.412, 74, (110); 3.121, 73, (310); 2.541, 58, ($\bar{2}$02); 3.386, 49, (131); 2.596, 45, (061); 2.338, 41, ($\bar{3}$51); and 2.164, 39, (261).

A reinvestigation of mayenite from the type locality, the Ettringer Bellerberg volcano near Mayen, Eifel district, Germany

2012 ◽  
Vol 76 (3) ◽  
pp. 707-716 ◽  
Author(s):  
E. V. Galuskin ◽  
J. Kusz ◽  
T. Armbruster ◽  
R. Bailau ◽  
I. O. Galuskina ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Raman Spectroscopy ◽  
Single Crystal ◽  
Electron Microprobe ◽  
Partial Substitution ◽  
Chemical Formula ◽  
Oh Groups ◽  
X Ray ◽  
Ray Methods ◽  
Original Formula

AbstractNew electron-microprobe analyses of mayenite from the Ettringer Bellerberg volcano near Mayen in the Eifel district, Germany have high Cl contents and Raman spectroscopy indicates the presence of OH groups. Neither of these components is included in the generally accepted chemical formula, Ca12Al14O33. A refinement of the crystal structure by single-crystal X-ray methods reveals a previously unrecognized partial substitution. The O2 site which forms one of the apices of an AlO4 tetrahedron (with 3 × O1 sites) is replaced by 3 × O2a sites, which change the coordination of the central Al atom from tetrahedral to octahedral. This substitution is related to partial hydration of Ca12Al14O32Cl2 according to the isomorphic scheme (O2– + Cl–) ↔ 3(OH)–. The revised composition of Eifel mayenite is best described by the formula Ca12Al14O32–xCl2–x(OH)3x (x ∼0.75); the original formula, Ca12Al14O33, is inadequate. The analysed mineral can be considered to consist of endmember Ca12Al14O32Cl2 (62.5 mol.%) and endmember Ca12Al14O30(OH)6 (37.5 mol.%).

Die Struktur des fehlgeordneten Kompositkristalls (LaS)1.18VS2: Eine Betrachtung als Domänenstruktur

1997 ◽  
Vol 212 (9) ◽  
Author(s):  
K. Friese ◽  
O. Jarchow ◽  
K. Kato
Keyword(s):  
Crystal Structure ◽  
Structure Factor ◽  
Integral Intensity ◽  
Structure Refinement ◽  
Crystal Structure Refinement ◽  
Disordered Structure ◽  
Domain Structures ◽  
Composite Crystal ◽  
Multiple Domains ◽  
Composite Crystals

AbstractA method for the crystal structure refinement of composite crystals with multiple domains of different symmetry is proposed and explained. For this a formula for the integral intensity of domain structures is given and a structure factor formula is derived. The method is applied to the disordered structure of the composite crystal (LaS)

scholarly journals Halilsarpite, a new arsenate analogue of walentaite, from the Oumlil mine, Bou Azzer district, Morocco

2020 ◽  
Vol 32 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Tomas Husdal ◽  
Ian E. Grey ◽  
Henrik Friis ◽  
Fabrice Dal Bo ◽  
Anthony R. Kampf ◽  
...  
Keyword(s):  
Crystal Structure ◽  
White Light ◽  
Electron Microprobe ◽  
Structure Refinement ◽  
Partial Replacement ◽  
Lemon Yellow ◽  
Crystal Structure Refinement ◽  
Calculated Density ◽  
X Ray ◽  
Perfect Cleavage

Abstract. Halilsarpite, [Mg(H2O)6][CaAs23+(Fe2.673+Mo0.336+)(AsO4)2O7], is a new secondary mixed arsenate/arsenite mineral from the Oumlil mine, Bou Azzer district, Morocco. It forms lemon-yellow spherules, about 0.1 mm in diameter, composed of platelets, some tens of micrometres in diameter but only 1–2 µm thick. The platelets are flattened on {100} and exhibit perfect cleavage on {100}. The calculated density is 2.89 g cm−3. Optically, halilsarpite is biaxial (−), with α=1.646(calc), β=1.765(5), γ=1.815(5) (white light), and 2V (meas.) = 62(1)∘. The partial orientation is X=a. Dispersion is weak with r<v, and pleochroism is in shades of yellow, X<Y≈Z. Electron microprobe analyses coupled with crystal-structure refinement results give the empirical formula [(Mg0.42Ca0.19Fe0.113+ □0.28)Σ1.00 (H2O)6][((Ca0.5Mg0.2Na0.11□0.14)Σ0.95 (As3+)2.05)∑3.00(Fe2.443+ Mo0.566+)Σ3.00 ((As0.9855+P0.0155+)Σ1.00O4)2O6.9(OH)0.1]. Halilsarpite is orthorhombic, Imma, with a=26.4890(10), b=7.4205(3), c=10.4378(4) Å, V=2051.67(14) Å3, and Z=4. The structure was solved and refined using single-crystal X-ray data to wRobs=0.046 for 1402 unique reflections to a resolution of 0.75 Å. Halilsarpite is isostructural with walentaite and natrowalentaite, which have structures based on heteropolyhedral layers of configuration [M1(M2)2(TO4)2(O,OH)6] with surface-attached As3+O3 groups and Ca and Na cations, and with interlayer hydrated cations and H2O molecules. The octahedrally coordinated sites M1 and M2 are occupied by Fe3+ in walentaite, while M2 = Fe0.673+W0.336+ in natrowalentaite. Walentaite and natrowalentaite are phosphates, with T=P5+. Halilsarpite differs from these minerals in having T=As5+ and in having partial replacement of Fe3+ by Mo6+ in the M2-centred octahedra.

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