Ralstonite Renamed Hydrokenoralstonite, Coulsellite Renamed Fluornatrocoulsellite, and Their Incorporation Into the Pyrochlore Supergroup

Atencio, Daniel; Andrade, Marcelo B.; Neto, Artur Cézar Bastos; Pereira, Vitor Paulo

doi:10.3749/canmin.1600056

Cited by 24 publications

(22 citation statements)

References 14 publications

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“…The results are given in Table 1. The minerals hydrokenoralstonite with Al in the B site (Atencio et al, 2017) and hydrokenoelsmoreite-3C with W 6+ in the B site, (Mills et al, 2016) both have measured tilt angles that agree with the value of 15.8°calculated from equation 1. These two minerals have almost perfect octahedra with X-B-X angles of 90°and all X-X edges equal.…”

Section: Pyrochlore Minerals and Htb-pyrochlore Intgergrowthssupporting

confidence: 70%

Kagomé networks of octahedrally coordinated metal atoms in minerals: Relating different mineral structures through octahedral tilting

Grey

2020

MinMag

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Kagomé nets of corner-connected triangles of atoms occur in diverse minerals, from the {111} anion arrays in perovskite-group minerals to natural metallic alloys like auricupride, AuCu3, to the cation layers in atacamite-group minerals. We review here two- and three-dimensional kagomé networks in minerals where the kagomé node atoms are octahedrally coordinated in hexagonal tungsten bronze (HTB) arrays. Octahedral tilting, coupled with capping of the apical anions of the triangular groupings of octahedra in the HTB layers, gives rise to several important mineral groups, including pyrochlores, alunite-supergroup minerals, zirconolite and weberite polytypes and spinel-group minerals, as a function of the magnitude and type of the octahedral tilting.

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Section: Pyrochlore Minerals and Htb-pyrochlore Intgergrowthssupporting

confidence: 70%

Kagomé networks of octahedrally coordinated metal atoms in minerals: Relating different mineral structures through octahedral tilting

Grey

2020

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“…The pyrochlore supergroup comprises seven groups: betafite, coulsellite, elsmoreite, microlite, pyrochlore, ralstonite and roméite, depending on the nature of the predominant B cation (Ti, Mg, W, Ta, Nb, Al and Sb, respectively) and X anion (O 2– in all groups except coulsellite and ralstonite, where the dominant anion is F – ) (Atencio et al , 2017).…”

Section: Introductionmentioning

confidence: 99%

Oxybismutomicrolite, a new pyrochlore-supergroup mineral from the Malkhan pegmatite field, Central Transbaikalia, Russia

Kasatkin

Britvin

Peretyazhko

et al. 2020

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Oxybismutomicrolite, ideally [(Bi3+,#)2]Σ4+Ta2O6O, where # = subordinate substituents, such as Na+, Ca2+ and vacancy (□), is a microlite-group, pyrochlore-supergroup mineral discovered at the Solnechnaya (‘Sunny’) pegmatite vein, Malkhan pegmatite field, Zabaykalskiy Kray, Central Transbaikalia, Russia. It forms rough octahedral crystals up to 1 mm across and equant grains up to 2 mm across embedded in an albite–lepidolite–elbaite complex. Other associated minerals are Bi-rich fluornatromicrolite, bismutotantalite and stibiotantalite. The new mineral is black, with resinous lustre; the streak is greyish white. It is non-fluorescent under ultraviolet light. Oxybismutomicrolite is brittle, with Mohs’ hardness of ~5. Cleavage is not observed, fracture is uneven. Dmeas. = 6.98(2) g/cm3 and Dcalc. = 7.056 g/cm3. The mineral is optically isotropic. The mean refractive index calculated from the Gladstone–Dale equation is 2.184. The infrared spectrum shows the absence of H2O molecules and OH groups. The chemical composition is (electron microprobe, wt.%): Na2O 3.45, CaO 2.88, MnO 0.31, PbO 0.76, Bi2O3 29.81, ThO2 0.18, TiO2 3.89, SnO2 1.77, Nb2O5 4.50, Ta2O5 51.08, F 1.17, O = F –0.49, total 99.31. The empirical formula, on the basis of 2 cations at the B site, is (Bi0.79Na0.68Ca0.32Mn0.03Pb0.02□0.16)Σ2.00(Ta1.42Ti0.30Nb0.21Sn0.07)Σ2.00O6.00(O0.52F0.38□0.10)Σ1.00. The crystal structure refinement (R = 0.019) gave the following data: cubic, Fd–3m, a = 10.4746(11) Å, V = 1149.2(4) Å3 and Z = 8. The eight strongest lines of the powder X-ray diffraction pattern [d, Å(I, %)(hkl)] are: 6.051(12)(111), 3.160(10)(311), 3.026(100)(222), 2.621(32)(400), 1.854(33)(440), 1.581(27)(622), 1.514(7)(444) and 1.203(7)(662). Type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia, registration number 5409/1.

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“…The second prefix refers to the dominant cation of the dominant valence (or H 2 O or □) at the A site. The root names are elsmoreite, pyrochlore, microlite, roméite, betafite, ralstonite and coulsellite, depending on the nature of the predominant B cation and X anion (Atencio et al , 2017). The dominant cations of the dominant valence at the B site are, respectively, W, Nb, Ta, Sb, Ti, Al and Mg. For elsmoreite, pyrochlore, microlite, roméite and betafite groups, the dominant anion of the dominant valence at the X site is O 2– .…”

Section: Introductionmentioning

confidence: 99%

“…The dominant cations of the dominant valence at the B site are, respectively, W, Nb, Ta, Sb, Ti, Al and Mg. For elsmoreite, pyrochlore, microlite, roméite and betafite groups, the dominant anion of the dominant valence at the X site is O 2– . For ralstonite and coulsellite groups, the dominant anion of the dominant valence at the X site is F – (Atencio et al , 2010, 2017; Christy and Atencio, 2013).…”

Section: Introductionmentioning

confidence: 99%

Kenoplumbomicrolite, (Pb,□)₂Ta₂O₆[□,(OH),O], a new mineral from Ploskaya, Kola Peninsula, Russia

et al. 2018

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This study presents a complete characterization of kenoplumbomicrolite, (Pb,□)2Ta2O6[□,(OH),O], occurring in an amazonite pegmatite from Ploskaya Mountain, Western Keivy Massif, Kola Peninsula, Murmanskaja Oblast, Northern Region, Russia.Kenoplumbomicrolite occurs in yellowish brown octahedral, cuboctahedral and massive crystals, up to 20 cm, has a white streak, a greasy lustre and is translucent. The Mohs hardness is ~6. Attempts to measure density (7.310–7.832 g/cm3) were affected by the ubiquitous presence of uraninite inclusions. Reflectance values were measured in air and immersed in oil. Kenoplumbocrolite is optically isotropic. The empirical formula is (Pb1.30□0.30Ca0.29Na0.08U0.03)Σ2.00(Ta0.82Nb0.62Si0.23Sn4+0.15Ti0.07Fe3+0.10Al0.01)Σ2.00O6[□0.52(OH)0.25O0.23]Σ1.00 (from the crystal used for the structural study) and (Pb1.33□0.66Mn0.01)Σ2.00(Ta0.87Nb0.72Sn4+0.18Fe3+0.11W0.08Ti0.04)Σ2.00O6[□0.80(OH)0.10O0.10]Σ1.00 (average including additional fragments). The mineral is cubic, space group Fd$\overline 3 $m. The unit-cell parameters refined from powder X-ray diffraction data are a = 10.575(2) Å and V = 1182.6(8) Å3, which are in accord with those obtained previously from a single crystal of a = 10.571(1) Å, V = 1181.3(2) Å3 and Z = 8. The mineral description and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2015-007a).

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Ralstonite Renamed Hydrokenoralstonite, Coulsellite Renamed Fluornatrocoulsellite, and Their Incorporation Into the Pyrochlore Supergroup

Cited by 24 publications

References 14 publications

Kagomé networks of octahedrally coordinated metal atoms in minerals: Relating different mineral structures through octahedral tilting

Kagomé networks of octahedrally coordinated metal atoms in minerals: Relating different mineral structures through octahedral tilting

Oxybismutomicrolite, a new pyrochlore-supergroup mineral from the Malkhan pegmatite field, Central Transbaikalia, Russia

Kenoplumbomicrolite, (Pb,□)₂Ta₂O₆[□,(OH),O], a new mineral from Ploskaya, Kola Peninsula, Russia

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Ralstonite Renamed Hydrokenoralstonite, Coulsellite Renamed Fluornatrocoulsellite, and Their Incorporation Into the Pyrochlore Supergroup

Cited by 24 publications

References 14 publications

Kagomé networks of octahedrally coordinated metal atoms in minerals: Relating different mineral structures through octahedral tilting

Kagomé networks of octahedrally coordinated metal atoms in minerals: Relating different mineral structures through octahedral tilting

Oxybismutomicrolite, a new pyrochlore-supergroup mineral from the Malkhan pegmatite field, Central Transbaikalia, Russia

Kenoplumbomicrolite, (Pb,□)2Ta2O6[□,(OH),O], a new mineral from Ploskaya, Kola Peninsula, Russia

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Kenoplumbomicrolite, (Pb,□)₂Ta₂O₆[□,(OH),O], a new mineral from Ploskaya, Kola Peninsula, Russia