Scheuchzerite, Na(Mn,Mg)9[VSi9O28(OH)](OH)3, a new single-chain silicate
-
,
Abstract
Scheuchzerite, Na(Mn,Mg)9[VSi9O28(OH)](OH)3, is a new mineral from the metamorphosed synsedimentary exhalative Mn deposit of Fianel, Val Ferrera, Central Alps, Switzerland. It is dedicated to the Swiss naturalist Johann Jakob Scheuchzer (1672.1733). Scheuchzerite is associated with saneroite and tiragalloite in veins resulting from the remobilization of ore components during retrograde Tertiary Alpine metamorphism. Scheuchzerite forms yellow-orange, transparent acicular crystals up to 0.5 mm in length with yellow-orange streak and vitreous luster, Mohs. hardness ~2.5, dcalc 3.47 (electron microprobe) to 3.52 g/cm3 (structure refinement); dmeas 3.50(2) g/cm3, good cleavage parallel to fiber elongation. Scheuchzerite is biaxial positive, nmin = 1.74 and nmax = 1.75; nmean (Gladstone-Dale) 1.74; weakly pleochroic, X = brown yellow, Y = pale yellow. The empirical chemical formula is Na0.97(Mn7.79Mg0.95Zn0.16Ni0.04Ca0.03Al0.01)Σ=8.98 (V0.95As0.02Si9.08)Σ=10.05O32.05H4. Scheuchzerite is triclinic, P1̅, a = 9.831(5) Å, b = 10.107(5) Å, c = 13.855(7) Å, α = 86.222(10)°, β = 73.383(9)°, γ = 71.987(9)°; V = 1254.2(10) Å3; Z = 2. The crystal structure was solved with direct methods on the basis of 1616 unique reflections with I > 4σF and refined to R1 = 9.4%. The crystal structure consists of tetrahedral layers separated by layers containing chains of edge-sharing [Mn(O,OH)6] octahedra as well as [NaO8] polydedra. The tetrahedral layers consist of [Si9O25(OH)] loop-branched chains of corner-sharing silicate tetrahedra extending along [011]. The loops contain 6 tetrahedra and are separated by 3 tetrahedra in a broken 4-loop arrangement. A hydrogen atom is probably shared by two O atoms (symmetrical hydrogen bond), replacing the missing silicon atom. A vanadate (VO4)3. tetrahedron branches off the 6-tetrahedra loop, and hence the overall formula of the tetrahedral chains is [VSi9O28(OH)]. In the notation of Liebau (1985), scheuchzerite is a single chain silicate (monopolysilicate) {olB1∞}[VSi9O28(OH)]. The topology of the scheuchzerite structure is reminiscent of that of the double-chain silicates of the amphibole group, but scheuchzerite contains a new type of silica chain.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- Hourglass sector zoning in metamorphic tourmaline and resultant major and trace-element fractionation
- Occurrence and late re-equilibration of pollucite from the Koktokay no. 3 pegmatite, Altai, northwestern China
- Chemical bonding and electronic structures of the Al2SiO5 polymorphs, andalusite, sillimanite, and kyanite: X-ray photoelectron- and electron energy loss spectroscopy studies
- Application of the simple salt lattice energy approximation to the solubility of minerals
- Quench rate and temperature effects on framework ordering in aluminosilicate melts
- The effect of sodium on the solubilities of metals in silicate melts
- Nanotunnels and pull-aparts: Defects of exsolution lamellae in alkali feldspars
- The structure and distribution of carbon in 3.5 Ga Apex chert: Implications for the biogenicity of Earth`s oldest putative microfossils
- Site disorder revealed through Raman spectra from oriented single crystals: A case study on karooite (MgTi2O5)
- Single-crystal diffraction and transmission electron microscopy studies of silicified pyrochlore from Narssârssuk, Julianehaab district, Greenland
- Compressibility of synthetic potassium-rich clinopyroxene: In-situ high-pressure single-crystal X-ray study
- The effect of Ca substitution on the elastic and structural behavior of orthoenstatite
- Dehydroxylation, proton migration, and structural changes in heated talc: An infrared spectroscopic study
- Stabilizing of methane hydrate and transition to a new high-pressure structure at 40 GPa
- Upper limit of the tetrahedral rotation angle and factors affecting octahedral flattening in synthetic and natural 1M polytype C2/m space group micas
- Cation order and hydrogen bonding of high-pressure phases in the Al2O3-SiO2-H2O system: An NMR and Raman study
- Relationship among metamorphic grade, vesuvianite ”rod polytypism”, and vesuvianite composition
- Assignment of infrared OH-stretching bands in calcic amphiboles through deuteration and heat treatment
- Direct determination of cation site occupancies in natural ferrite spinels by L2,3 X-ray absorption spectroscopy and X-ray magnetic circular dichroism
- Heat capacities and entropies of mixing of pyrope-grossular (Mg3Al2Si3O12-Ca3Al2Si3O12) garnet solid solutions: A low-temperature calorimetric and a thermodynamic investigation
- Fe2+ and Fe3+ quantification by different approaches and fO₂ estimation for Albanian Cr-spinels
- Inversion twinning in troilite
- Chivruaiite, Ca4(Ti,Nb)5[(Si6O17)2[(OH,O)5]·13-14H2O, a new mineral from hydrothermal veins of Khibiny and Lovozero alkaline massifs
- Pseudojohannite from Jáchymov, Musonoï, and La Creusaz: A new member of the zippeite-group
- Scheuchzerite, Na(Mn,Mg)9[VSi9O28(OH)](OH)3, a new single-chain silicate
- Mn-tourmaline crystals from island of Elba (Italy): Growth history and growth marks
- The oxidation state of vanadium in titanomagnetite from layered basic intrusions
- Observation of bicarbonate in calcite by NMR spectroscopy
- Single-crystal elastic properties of dense hydrous magnesium silicate phase A
Articles in the same Issue
- Hourglass sector zoning in metamorphic tourmaline and resultant major and trace-element fractionation
- Occurrence and late re-equilibration of pollucite from the Koktokay no. 3 pegmatite, Altai, northwestern China
- Chemical bonding and electronic structures of the Al2SiO5 polymorphs, andalusite, sillimanite, and kyanite: X-ray photoelectron- and electron energy loss spectroscopy studies
- Application of the simple salt lattice energy approximation to the solubility of minerals
- Quench rate and temperature effects on framework ordering in aluminosilicate melts
- The effect of sodium on the solubilities of metals in silicate melts
- Nanotunnels and pull-aparts: Defects of exsolution lamellae in alkali feldspars
- The structure and distribution of carbon in 3.5 Ga Apex chert: Implications for the biogenicity of Earth`s oldest putative microfossils
- Site disorder revealed through Raman spectra from oriented single crystals: A case study on karooite (MgTi2O5)
- Single-crystal diffraction and transmission electron microscopy studies of silicified pyrochlore from Narssârssuk, Julianehaab district, Greenland
- Compressibility of synthetic potassium-rich clinopyroxene: In-situ high-pressure single-crystal X-ray study
- The effect of Ca substitution on the elastic and structural behavior of orthoenstatite
- Dehydroxylation, proton migration, and structural changes in heated talc: An infrared spectroscopic study
- Stabilizing of methane hydrate and transition to a new high-pressure structure at 40 GPa
- Upper limit of the tetrahedral rotation angle and factors affecting octahedral flattening in synthetic and natural 1M polytype C2/m space group micas
- Cation order and hydrogen bonding of high-pressure phases in the Al2O3-SiO2-H2O system: An NMR and Raman study
- Relationship among metamorphic grade, vesuvianite ”rod polytypism”, and vesuvianite composition
- Assignment of infrared OH-stretching bands in calcic amphiboles through deuteration and heat treatment
- Direct determination of cation site occupancies in natural ferrite spinels by L2,3 X-ray absorption spectroscopy and X-ray magnetic circular dichroism
- Heat capacities and entropies of mixing of pyrope-grossular (Mg3Al2Si3O12-Ca3Al2Si3O12) garnet solid solutions: A low-temperature calorimetric and a thermodynamic investigation
- Fe2+ and Fe3+ quantification by different approaches and fO₂ estimation for Albanian Cr-spinels
- Inversion twinning in troilite
- Chivruaiite, Ca4(Ti,Nb)5[(Si6O17)2[(OH,O)5]·13-14H2O, a new mineral from hydrothermal veins of Khibiny and Lovozero alkaline massifs
- Pseudojohannite from Jáchymov, Musonoï, and La Creusaz: A new member of the zippeite-group
- Scheuchzerite, Na(Mn,Mg)9[VSi9O28(OH)](OH)3, a new single-chain silicate
- Mn-tourmaline crystals from island of Elba (Italy): Growth history and growth marks
- The oxidation state of vanadium in titanomagnetite from layered basic intrusions
- Observation of bicarbonate in calcite by NMR spectroscopy
- Single-crystal elastic properties of dense hydrous magnesium silicate phase A
