SwePub
Sök i SwePub databas

  Utökad sökning

Booleska operatorer måste skrivas med VERSALER

Träfflista för sökning "AMNE:(NATURAL SCIENCES Earth and Related Environmental Sciences Geochemistry) ;pers:(Pasero Marco)"

Sökning: AMNE:(NATURAL SCIENCES Earth and Related Environmental Sciences Geochemistry) > Pasero Marco

  • Resultat 1-10 av 38
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Biagion, Cristian, et al. (författare)
  • The crystal structure of turneaureite, Ca5(AsO4)3Cl, the arsenate analog of chlorapatite and its relationships with the arsenate apatites johnbaumite and svabite
  • 2017
  • Ingår i: American Mineralogist. - : Mineralogical Society of America. - 0003-004X .- 1945-3027. ; 102, s. 1981-1986
  • Tidskriftsartikel (refereegranskat)abstract
    • The crystal structure of turneaureite, ideally Ca5(AsO4)3Cl, was studied using a specimen from the Brattfors mine, Nordmark, Värmland, Sweden, by means of single-crystal X-ray diffraction data. The structure was refinedto R1 = 0.017 on the basis of 716 unique reflectios with Fo > 4σ(Fo) in the P63/m space group, with unit-cell parameters a = 9.9218(3), c = 6.8638(2) Å, V = 585.16(4) Å3. The chemical composition of the sample, determined by electron-microprobe analysis, is (in wt%; average of 10 spot analyses): SO3 0.22, P2O5 0.20, V2O5 0.01, As2O5 51.76, SiO2 0.06, CaO 41.39, MnO 1.89, SrO 0.12, BaO 0.52, PbO 0.10, Na2O 0.02, F 0.32, Cl 2.56, H2Ocalc 0.58, O(≡F+Cl) –0.71, total 99.04. On the basis of 13 anions per formula unit, the empirical formula corresponds to (Ca4.82Mn0.17Ba0.02Sr0.01)∑5.02 (As2.94P0.02S0.02Si0.01)∑2.99O12[Cl0.47(OH)0.42F0.11]∑1.00.Turneaureite is topologically similar to the other members of the apatite supergroup: columns of face-sharing M1 polyhedra running along c are connected through TO4 tetrahedra with channels hosting M2 cations and X anions. Owing to its particular chemical composition, the studied turneaureite can be considered as a ternary calcium arsenate apatite; consequently it has several partially filledanion sites within the anion columns. Polarized single-crystal FTIR spectra of the studied sample indicate stronger hydrogen bonding and less diverse short-range atom arrangements around (OH) groups in turneaureite as compared to the related minerals johnbaumite and svabite. An accurate knowledge of the atomic arrangement of this apatite-remediation mineral represents an improvement in our understanding of minerals able to sequester and stabilize heavy metals such as arsenic in polluted areas.
  •  
2.
  • Biagioni, Cristian, et al. (författare)
  • Bianchiniite, Ba2(Ti4+V3+)(As2O5)2OF, a new diarsenite mineral fromthe Monte Arsiccio mine, Apuan Alps, Tuscany, Italy
  • 2021
  • Ingår i: Mineralogical magazine. - : Mineralogical Society. - 0026-461X .- 1471-8022. ; 3, s. 354-363
  • Tidskriftsartikel (refereegranskat)abstract
    • The new mineral bianchiniite, Ba2(Ti4+V3+)(As2O5)2OF, has been discovered in the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy. It occurs as brown {001} tabular crystals, up to 1 mm across, with a vitreous lustre. It is brittle, with a perfect {001} cleavage. Streak is brownish. In reflected light, bianchiniite is grey, with orange–yellow internal reflections. It is weakly bireflectant, with a very weak anisotropy in shades of grey. Minimum and maximum reflectance data for COM wavelengths [Rmin/Rmax (%), (λ, nm)] are: 5.0/5.8 (470),5.7/6.5 (546), 5.7/7.0 (589) and 5.2/6.3 (650). Electron microprobe analyses gave (wt.% – average of 10 spot analyses): TiO2 10.34, V2O33.77, Fe2O3 3.76,As2O3 44.36, Sb2O3 0.22, SrO 0.45, BaO 34.79, PbO 0.28, F 1.77, sum 99.74, –O=F–0.75, total 98.99. On the basis of 12 anions per formula unit, the empirical formula of bianchiniite is (Ba2.00Sr0.04Pb0.02)Σ2.06(Ti4+1.14V3+0.44Fe3+0.42)Σ2.00[(As3.96Sb0.02)Σ3.98O10](O1.18F0.82)Σ2.00. Bianchiniite is tetragonal, space group I4/mcm, with unit-cell parameters a = 8.7266(4), c = 15.6777(7) Å, V = 1193.91(12) Å3 and Z = 8. Its crystal structure was refined from single-crystal X-ray diffraction data to R1 = 0.0134 on the basis of 555 unique reflections with Fo > 4σ(Fo)and 34 refined parameters. The crystal structure shows columns of corner-sharing [Ti/(V,Fe)]-centred octahedra running along c, connected along a and b through (As2O5) dimers. A {001} layer of Ba-centred [10+2]-coordinated polyhedra is intercalated between (As2O5) dimers. Bianchiniite has structural relations with fresnoite- and melilite-group minerals. The name honours the two mineral collectors Andrea Bianchini (b. 1959) and Mario Bianchini (b. 1962) for their contribution to the knowledge of the mineralogy of pyrite ± baryte ± iron-oxide ore deposits from the Apuan Alps.
  •  
3.
  •  
4.
  • Biagioni, Cristian, et al. (författare)
  • Nuove specie mineralogiche Italiane
  • 2019
  • Ingår i: Rivista Mineralogica Italiana. ; 43:4, s. 256-262
  • Tidskriftsartikel (populärvet., debatt m.m.)
  •  
5.
  • Biagioni, Cristian, et al. (författare)
  • Nuovi minerali Italiana - La approvazioni 2017
  • 2018
  • Ingår i: Revista Mineralogica Italiana. - Milano, Italy. - 0391-9641. ; 42:3, s. 190-197
  • Tidskriftsartikel (populärvet., debatt m.m.)
  •  
6.
  • Biagioni, Cristian, et al. (författare)
  • The crystal structure of svabite, Ca5(AsO4)3F, an arsenate member of the apatite supergroup
  • 2016
  • Ingår i: American Mineralogist. - : Mineralogical Society of America. - 0003-004X .- 1945-3027. ; 101, s. 1750-1755
  • Tidskriftsartikel (refereegranskat)abstract
    • The crystal structure of svabite, ideally Ca5(AsO4)3F, was studied using a specimen from the Jakobsberg mine, Värmland, Sweden, by means of single-crystal X‑ray diffraction data. The structure was refined to R1 = 0.032 on the basis of 928 unique reflections with Fo > 4s(Fo) in the P63/m space group, with unit-cell parameters a = 9.7268(5), c = 6.9820(4) Å, V = 572.07(5) Å3. The chemical composition of the sample, determined by electron-microprobe analysis, is (in wt%, average of 10 spot analyses): SO3 0.49, P2O5 0.21, V2O5 0.04, As2O5 51.21, SiO2 0.19, CaO 39.31, MnO 0.48, SrO 0.03, PbO 5.19, Na2O 0.13, F 2.12, Cl 0.08, H2Ocalc 0.33, O (≡ F+Cl) –0.91, total 98.90. On the basis of 13 anions per formula unit, the empirical formula corresponds to (Ca4.66Pb0.16Mn0.04Na0.03)Σ4.89(As2.96S0.04Si0.02P0.02)Σ3.04O12[F0.74(OH)0.24Cl0.01]. Svabite is topologically similar to the other members of the apatite supergroup: columns of face-sharing M1 polyhedra running along c are connected through TO4 tetrahedra with channels hosting M2 cations and X anions. The crystal structure of synthetic Ca5(AsO4)3F was previously reported as triclinic. On the contrary, the present refinement of the crystal structure of svabite shows no deviations from the hexagonal symmetry. An accurate knowledge of the atomic arrangement of this apatite-remediation mineral represents an improvement in our understanding of minerals able to sequester and stabilize heavy metals such as arsenic in polluted areas.
  •  
7.
  •  
8.
  • Bosi, Ferdinando, et al. (författare)
  • On the application of the IMA-CNMNC dominant-valency rule to complex mineral compositions
  • 2019
  • Ingår i: Mineralogical magazine. - : Mineralogical Society. - 0026-461X .- 1471-8022. ; 83:5, s. 627-632
  • Tidskriftsartikel (refereegranskat)abstract
    • Mineral species should be identified by an end-member formula and by using the dominant-valency rule as recommended by the IMA–CNMNC. However, the dominant-end-member approach has also been used in the literature. These two approaches generally converge, but for some intermediate compositions, significant differences between the dominant-valency rule and the dominant end-member approach can be observed. As demonstrated for garnet-supergroup minerals, for example, the end-member approach is ambiguous, as end-member proportions strongly depend on the calculation sequence. For this reason, the IMA–CNMNC strongly recommends the use of the dominant-valency rule for mineral nomenclature, because it alone may lead to unambiguous mineral identification. Although the simple application of the dominant-valency rule is successful for the identification of many mineral compositions, sometimes it leads to unbalanced end-member formulae, due to the occurrence of a coupled heterovalent substitution at two sites along with a heterovalent substitution at a single site. In these cases, it may be useful to use the site-total-charge approach to identify the dominant root-charge arrangement on which to apply the dominant-constituent rule. The dominant-valency rule and the site-totalcharge approach may be considered two procedures complementary to each other for mineral identification. Their critical point is to find the most appropriate root-charge and atomic arrangements consistent with the overriding condition dictated by the end-member formula. These procedures were approved by the IMA−CNMNC in May 2019.
  •  
9.
  • Grew, Edward S., et al. (författare)
  • Recommended nomenclature for the sapphirine and surinamite groups (sapphirine supergroup)
  • 2008
  • Ingår i: Mineralogical magazine. - : Mineralogical Society. - 0026-461X .- 1471-8022. ; 72, s. 839-876
  • Tidskriftsartikel (refereegranskat)abstract
    • Minerals isostructural with sapphirine-1A, sapphirine-2M, and surinamite are closely related chain silicates that pose nomenclature problems because of the large number of sites and potential constituents, including several (Be, B, As, Sb) that are rare or absent in other chain silicates. Our recommended nomenclature for the sapphirine group (formerly aenigmatite group) makes extensive use of precedent, but applies the rules to all known natural compositions, with flexibility to allow for yet undiscovered compositions such as those reported in synthetic materials. These minerals are part of a polysomatic series composed of pyroxene or pyroxene-like and spinel modules, and thus we recommend that the sapphirine supergroup should encompass the polysomatic series. The first level in the classification is based on polysome, i.e. each group within the supergroup corresponds to a single polysome. At the second level, the sapphirine group is divided into subgroups according to the occupancy of the two largestMsites, namely, sapphirine (Mg), aenigmatite (Na), and rhönite (Ca). Classification at the third level is based on the occupancy of the smallestMsite with most shared edges,M7, at which the dominant cation is most often Ti (aenigmatite, rhönite, makarochkinite), Fe3+(wilkinsonite, dorrite, høgtuvaite) or Al (sapphirine, khmaralite); much less common is Cr (krinovite) and Sb (welshite). At the fourth level, the two most polymerizedTsites are considered together, e.g. ordering of Be at these sites distinguishes høgtuvaite, makarochkinite and khmaralite. Classification at the fifth level is based on XMg= Mg/(Mg + Fe2+) at theMsites (excluding the two largest andMl). In principle, this criterion could be expanded to include other divalent cations at these sites, e.g. Mn. To date, most minerals have been found to be either Mg-dominant (XMg> 0.5), or Fe2+-dominant (XMg< 0.5), at theseMsites. However, XMgranges from 1.00 to 0.03 in material described as rhönite, i.e. there are two species present, one Mg-dominant, the other Fe2+-dominant. Three other potentially new species are a Mg-dominant analogue of wilkinsonite, rhönite in the Allende meteorite, which is distinguished from rhonite and dorrite in that Mg rather than Ti or Fe3+is dominant atMl, and an Al-dominant analogue of sapphirine, in which Al > Si at the two most polymerizedTsitesvs. Al < Si in sapphirine. Further splitting of the supergroup based on occupancies other than those specified above is not recommended.
  •  
10.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 38

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy