著者

Kazumasa SUGIYAMA Toru KAWAMATA Takahiro KURIBAYASHI

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

pp.210318, (Released:2021-11-09)

被引用文献数

1

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The crystal structure of prehnite Ca2(Al, Fe)(Si3AlO10)(OH)2 from Upper New Street Quarry, Paterson, Passaic County, New Jersey, USA was determined by single–crystal X–ray diffraction. The converged structural model in the space group P 2cm [a = 4.63309(9) Å, b = 5.4839(1) Å, c = 18.5100(3) Å, Z = 2] allowed for the investigation of an ordered Si/Al distribution together with the feasible hydrogen positions inferred from the difference Fourier maps.

著者

Massimo NESPOLO Tohru OZAWA Yusuke KAWASAKI Kazumasa SUGIYAMA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

vol.107, no.6, pp.226-243, 2012 (Released:2012-12-29)

参考文献数

32

被引用文献数

7 10

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The structure of quatrandorite is reported for the first time from an untwinned sample from Oura mine, San Jose, Bolivia. The mineral crystallizes in P21/c, a = 19.1686 (19) Å, b = 17.160 (3) Å, c = 13.042 (2) Å, β = 90.008 (12)°, V = 4289.9 (11) Å3, Z = 4. Refinement to Robs = 5.66% was obtained with Jana2006. Quatrandorite belongs to the andorite series, whose members share two cell parameters while the third can be expressed as n × 4.3 Å, with n = 2, 4 and 6 for ramdohrite (uchucchacuaite, fizelyite), quatrandorite and senandorite, respectively. Both quatrandorite and senandorite are strongly pseudosymmetric up to Cmcm with one parameter corresponding to n = 1 (∼ 4.3 Å). The hypothetical structure corresponding to Cmcm is also the aristotype common to both minerals. The strong structural similarity of quatrandorite and senandorite may explain their co-existence in some samples, which has in the past led to hypothesize the existence of a further member of the series, nakaséite, which was however later shown to consist of a random stacking of the two minerals. The Cmcm aristotype is not common to the n = 2 minerals (uchucchacuaite, ramdohrite, fizelyite), which are thus structurally less closely related to the two other members. A common aristotype to all three minerals can nevertheless be obtained via a different path, which leads to Cmme with the same cell parameters as Cmcm; the degree of pseudo-symmetry in this supergroup is however lower and there remain a difference in one sulfur position in this aristotype. It nevertheless confirms previous reports in the literature stating that the bulk of the structure of the minerals of this series can be reduced to a common principle, essentially a distorted galena; the departures from it are however crucial for the realization of the individual structures.

著者

Hidetomo HONGU Akira YOSHIASA Ginga KITAHARA Yumiko MIYANO Karin HAN Koichi MOMMA Ritsuro MIYAWAKI Makoto TOKUDA Kazumasa SUGIYAMA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

pp.200904, (Released:2021-09-30)

被引用文献数

2

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Parasymplesite and vivianite specimens were obtained from Kiura Mine, Ohita, Japan and Tomigaoka, Nara, Japan, respectively. Empirical chemical formulas of the specimens determined by energy–dispersive X–ray spectroscopy on the scanning electron microscopy were Fe3(AsO4)2·8H2O, and (Fe0.93Mn0.06Mg0.01)3(PO4)2·8H2O, respectively. The crystal structures of parasymplesite and vivianite determined by single–crystal X–ray diffraction method were monoclinic, space group C2/m, with unit–cell parameters: a = 10.3519(10), b = 13.6009(13), c = 4.7998(4) Å, β = 104.816(2)°, V = 653.32(11) Å3 (Z = 4), and monoclinic, space group C2/m, with unit–cell parameters: a = 10.1518(6), b = 13.4327(7), c = 4.7005(3) Å, β = 104.692(2)°, V = 620.03(6) Å3 (Z = 4), respectively. The crystal structure of parasymplesite solved with the ideal chemical formula was refined to the R1 value of 0.0301 (wR2 = 0.0788) for 722 independent reflections with |Fo| > 4σ(|Fo|), whereas that of vivianite was refined to the R1 value of 0.0272 (wR2 = 0.0832) for 664 independent reflections. The hydrogen atom positions determined by the difference Fourier method coincided with the positions where residual electron density peaks appeared. In the edge–sharing Fe2O6(H2O)4 double octahedra in parasymplesite and vivianite, the bond distance of Fe2–O5, where O5 is the oxygen atom of the H2O molecule, is shorter than that of Fe2–O2. In each arsenate and phosphate phase, only the M2–O2 bond distance shows an increase trend with the increase in the average ionic radii of the M2 site, but the M2–O3 bond distance never shows a clear average M2 ionic radius dependence. In vivianite group minerals, a distortion at the isolated M1O2(H2O)4 octahedra increases as a function of the average M1 ionic radius. The respective complex sheets consisting of the TO4 tetrahedra, isolated M1 octahedra, and edge–sharing M2 double octahedra are connected only by the hydrogen bond O5–H52•••O4. In the arsenate phases, the donor–acceptor distance between O5 and O4 exhibits an increase trend as increase of the average M ionic radius, but in the phosphate phases, there is no clear correlation between donor–acceptor distances and the average M ionic radius.

著者

Ginga KITAHARA Akira YOSHIASA Makoto TOKUDA Tsubasa TOBASE Kazumasa SUGIYAMA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

vol.116, no.1, pp.45-55, 2021 (Released:2021-03-06)

参考文献数

43

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Structural analysis of Ce– and Nb–perovskites containing Fe, Zr, Nb, and rare earth elements (REEs) in CaTiO3 perovskite was performed using single–crystal X–ray diffraction and X–ray absorption near–edge structure (XANES) analyses. Based on chemical analysis results, XANES measurements and the site–occupation of elements at A– and B–sites showed the chemical formula:(Ca2+0.817REE3+0.087Na+0.081Sr2+0.005Th4+0.003)1.998+0.993(Ti4+0.941Nb5+0.017Fe3+0.013V5+0.010Fe2+0.007Sc3+0.006Zn2+0.005Al3+0.002Ge4+0.001W6+0.001)3.996+1.003O3 for Ce–perovskite and(Ca2+0.937Ce3+0.021Na+0.020La3+0.015Sr2+0.003)2.008+0.996(Ti4+0.730Nb5+0.122Fe3+0.108Al3+0.020Zr4+0.009V5+0.008)3.990+0.997O3for Nb–perovskite. In Ce– and Nb–perovskites, the total charges at the A– and B–sites achieved near–ideal divalent and tetravalent states such as Ca2+Ti4+O3, respectively, due to complex elemental substitutions. Local distortions around Ti in the perovskite solid solutions were greater, and the pre–edge features of the Ti atoms in Ce– and Nb–perovskites were different from those in pure CaTiO3. The valence states and local structures of Fe in Ce– and Nb–perovskites were significantly different. The existence of divalent Fe2+ at the B–site in Ce–perovskite was confirmed. It is presumed that the displacement ellipsoids of all atoms and local irregularities in Ce–perovskite increase owing to the radiative decay of the actinoid element Th. We reconfirmed that the composition and three–dimensional structure of perovskite–type structures were flexible and caused various electrical, structural changes.