Crystal structure of kristiansenite: a case of class IIB twinning by metric merohedry

Ferraris, Giovanni; Gula, Angela; Ivaldi, Gabriella; Nespolo, M.; Raade, Gunnar

doi:10.1524/zkri.216.8.442.20353

Cited by 17 publications

(34 citation statements)

References 15 publications

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“…which is in good agreement with the previously reported formula (Ferraris et al, 2000;Khomyakov et al, 2001 In accordance with others members of LGM, the structure of labuntsovite-Fe consists of undulated chains (rods) formed by M1Ø 6 -and ] 2 }. The distortion of octahedral chains results in the deformation of the siliconoxygen rings.…”

Section: Peculiarity Of Labuntsovite-fe Structuresupporting

confidence: 92%

“…In disordered LGM (space group Cm) the sites A, B and C are split into numerous subsites with low occupancy factors. Labuntsovite-Fe, the Fe-dominant member of the labuntsovite group, was first discovered in the Khibiny alkaline massif on Mt Kukisvumchorr (Ferraris et al, 2000;Khomyakov et al, 2001). The unit-cell parameters of the holotype sample are: a = 14.249 (6), b = 13.791 (6), c = 7.777 (2) Å , = 116.82 ; space group C2/m.…”

Section: Introductionmentioning

confidence: 99%

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Microporous crystal structure of labuntsovite-Fe and high-pressure behavior up to 23 GPa

Aksenov

Bykova

Расцветаева

et al. 2018

Acta Crystallogr B Struct Sci Cryst Eng Mater

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Labuntsovite-Fe, an Fe-dominant member of the labuntsovite subgroup, was first discovered in the Khibiny alkaline massif on Mt Kukisvumchorr . Zap. Vseross. Mineral. Oba, 130,[36][37][38][39][40][41][42][43][44][45]. However, no data are published about the crystal structure of this mineral. Labuntsovite-Fe from a peralkaline pegmatite located on Mt Nyorkpakhk, in the Khibiny alkaline complex, Kola Peninsula, Russia, has been investigated by means of electron microprobe analyses, single-crystal X-ray structure refinement, and IR and Raman spectroscopies. Monoclinic unit-cell parameters of labuntsovite-Fe are: a = 14.2584 (4), b = 13.7541 (6), c = 7.7770 (2) Å , = 116.893 (3) ; V = 1360.22 (9) Å 3 ; space group C2/m. The structure was refined to final R 1 = 0.0467, wR 2 = 0.0715 for 3202 reflections [I > 3(I)]. The refined crystal chemical formula is (Z = 2): Na 2 K 2 Ba 0.7 [(Fe 0.5 Ti 0.1 Mg 0.05 )(H 2 O) 1.3 ]{[Ti 2 (Ti 1.9 Nb 0.1 )-(O,OH) 4 ][Si 4 O 12 ] 2 }Á4H 2 O.The high-pressure in situ single-crystal X-ray diffraction study of the labuntsovite-Fe has been carried out in a diamond anvil cell. The labuntsovite-type structure is stable up to 23 GPa and phase transitions are not observed. Calculations using the BM3 equation of state resulted in the bulk modulus K = 72 (2) GPa, K 0 0 = 3.7 (2) and V 0 = 1363 (2) Å 3 . Compressing of the heteropolyhedral zeolite-like framework leads to the deformation of main structural units. Octahedral rods show the gradual increase of distortion and the wave-like character of rods becomes more distinct. Rod deformations result in the distortion of the silicon-oxygen ring which is not equal in different directions. Structural channels are characterized by a different ellipticitypressure relationship: the cross-section of the largest channel I and channel II demonstrates the stability of the geometrical characteristics which practically do not depend on pressure: " channel I ' 0.85 (4) (cross-section is rather regular) and " channel II ' 0.52 (2) within the whole pressure range. However, channel III is characterized by the increasing of ellipticity with pressure (" = 0.40 ! 0.10).

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Section: Peculiarity Of Labuntsovite-fe Structuresupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Microporous crystal structure of labuntsovite-Fe and high-pressure behavior up to 23 GPa

Aksenov

Bykova

Расцветаева

et al. 2018

Acta Crystallogr B Struct Sci Cryst Eng Mater

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“…The structure was solved by direct methods [30] in the monoclinic space group C2/c, as indicated by experiment, using neutral atom scattering factors, and refined to an R 1 index of 6.45% with anisotropic displacement parameters. However, in their original description of kristiansenite, Ferraris et al [6] found that the crystals of kristiansenite typically show metric merohedral twinning. While the underlying structure including cation ordering is triclinic, the twin law belonging to the higher Laue group makes the structure appear monoclinic within experimental error.…”

Section: Crystal Structure Refinementmentioning

confidence: 99%

“…The position of Ca1 was fixed arbitrarily as the origin. Following [6], the structure was refined to an R 1 index of 4.96% in the unconventional triclinic space group setting C1.…”

Section: Crystal Structure Refinementmentioning

confidence: 99%

“…Recently, Výravsky et al [5] noted the presence of kristiansenite in the intragranitic NYF-affilliated pegmatite Kožichovice II, Třebíč pluton, Czech Republic, as a product of late Ca metasomatism of the primary thortveitite, Sc 2 Si 2 O 7 . The crystal structure of type kristiansenite from Norway (triclinic; space group-symmetry C1, Z = 2) was solved by Ferraris et al [6].…”

Section: Introductionmentioning

confidence: 99%

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Crystal Structure of Kristiansenite from Szklarska Poręba, Southwestern Poland

et al. 2018

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Kristiansenite, ideally Ca2ScSn(Si2O7)(Si2O6OH), a rare late-stage hydrothermal Sc-bearing sorosilicate mineral, was found in a gadolinite-fergusonite-type pegmatite of the MI-REE subclass related to the Karkonosze granite, exposed in a quarry at Szklarska Poręba, Lower Silesia, Poland. Kristiansenite occurs in an association with andradite, epidote, allanite-(Ce), titanite, fersmite, scheelite, Sc-bearing columbite-(Fe), a YNbO4 mineral as fergusonite-(Y) or fergusonite-(Y)-beta, silesiaite and wolframite. Single-crystal study of the mineral (R1 of 4.96%), with composition Ca2.00(Sn0.97Sc0.69Fe3+0.17Mn0.05Ti0.04Zr0.03Nb0.02Al0.02Ta0.01)Σ2(Si2O7)[(Si1.98Al0.02)Σ2O6.03(OH)0.97], corroborates its triclinic structure with space group-symmetry C1, Z = 2, and unit-cell parameters a = 10.0304(5), b = 8.4056(4), c = 13.3228(6) Å, α = 90.001(3), β = 109.105(3), γ = 89.997(3)° and V = 1061.40(9) Å3. In the structure of the mineral, the Ca and Si sites are dominantly occupied with Ca and Si, whereas the M1–M4 sites are disordered. The M3 and M4 sites are occupied dominantly by Sn and subordinately Sc, whereas the M1 and M2 sites are occupied dominantly by Sc and subordinately by remaining occupants, including Sn.

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Characterization of the cathodoluminescence emission of kamphaugite-(Y) and kristiansenite from Spain

Correcher

García-Guinea

2020

Phys Chem Minerals

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Crystal structure of kristiansenite: a case of class IIB twinning by metric merohedry

Abstract: The structure of the new disilicate kristiansenite, Ca

Cited by 17 publications

References 15 publications

Microporous crystal structure of labuntsovite-Fe and high-pressure behavior up to 23 GPa

Microporous crystal structure of labuntsovite-Fe and high-pressure behavior up to 23 GPa

Crystal Structure of Kristiansenite from Szklarska Poręba, Southwestern Poland

Characterization of the cathodoluminescence emission of kamphaugite-(Y) and kristiansenite from Spain

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