G. W. Leibniz: Monadology

Burnham, Douglas

doi:10.1017/upo9781844653591.005

Cited by 7 publications

(7 citation statements)

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“…The positions and intensities of diffraction peaks were found and refined using the Pearson VII profile‐shape function of the ZDS program package and indexed using theoretical pattern calculated from the crystal‐structure data of chalcostibite . The unit‐cell parameters were refined by the least‐squares program by Burnham …”

Section: Methodsmentioning

confidence: 99%

Micro‐Raman spectroscopy of natural members along CuSbS₂–CuSbSe₂ join

Sejkora

Buixaderas

Škácha

et al. 2018

J Raman Spectroscopy

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Micro‐Raman spectroscopy was used to investigate the natural orthorhombic members (space group Pnma) along the CuSbS2–CuSbSe2 join: chalcostibite Cu1.01Sb1.00S1.99 from Dúbrava (Slovak Republic); Se‐rich chalcostibite Cu1.00(Sb0.99As0.02)Σ1.01(S1.29Se0.70)Σ1.99 and the new mineral příbramite Cu0.99(Sb1.03As0.01)Σ1.04(Se1.82S0.15)Σ1.97 both from the Příbram uranium and base‐metal district (Czech Republic). Stretching and bending vibrations of the pyramidal SbS3 groups occur between 350 and 200 cm−1; vibrations of SbSe3 groups are shifted to the range 240–80 cm−1 due to the almost twice heavier mass of Se compared with S. The shift of the ν1 symmetric Sb‐(S,Se) vibration was observed, yielding 113 cm−1, and for the ν3 antisymmetric stretching Sb‐(S,Se), vibration was about 127 cm−1. The wavenumber of the ν1 symmetric Sb–S stretching vibrations decreases with increasing Se content—from 336 (in chalcostibite) over 330 (in Se‐rich chalcostibite) to 326 cm−1 (in příbramite), and a similar situation was observed for the case of ν1 symmetric Sb–Se stretching vibrations from 220 in Se‐rich chalcostibite to 215 cm−1 in příbramite. The trend for the ν3 antisymmetric Sb‐(S,Se) stretching vibrations is the opposite, from 306 cm−1 in chalcostibite to 314 cm−1 in Se‐rich chalcostibite (Sb–S bonds) and from 180 cm−1 in Se‐rich chalcostibite to 185 cm−1 in příbramite (Sb–Se bonds). These small shifts are probably connected with the influencing of the bonding environment of SbS3 and SbSe3 pyramids. The vibrations of Cu‐S(Se) bonds are represented only by less intense bands, and the observed intense bands below 80 cm−1 should correspond to external modes.

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Section: Methodsmentioning

confidence: 99%

Micro‐Raman spectroscopy of natural members along CuSbS₂–CuSbSe₂ join

Sejkora

Buixaderas

Škácha

et al. 2018

J Raman Spectroscopy

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“…No changes were observed apart from a drastic reduction of the cell dimensions (11% in volume) from a=9.792 (2), b= 13-644 (3), c=9.629 (2) A, V=1286.5 (3) A3 in the hydrated state , to a=9.368 (2), b= 12.808 (3), c=9.550 (2) A, V=1145.8 (3) /~3 in the dehydrated state. The cell dimensions in the dehydrated form were determined by the least-squares refinement of 23 high 20 values (Burnham, 1962) measured on a Picker FACS-I diffractometer at room temperature and obtained by averaging four half-height peak settings (plus and minus 20). No change in the space group was observed upon dehydration.…”

Section: Methodsmentioning

confidence: 99%

Crystal structure of cavansite dehydrated at 220°C

Rinaldi¹,

Pluth²,

Smith³

1975

Acta Crystallogr Sect B

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A single crystal of the new mineral cavansite, Ca(VO) (Si4010).4H20, from the type locality (Malheur County, Oregon) was dehydrated at 220_+ 10°C in a quartz capillary at ~ 10 -5 atm for 24 h. Intensity data from a four-circle diffractometer were refined anisotropically by least-squares calculations and Fourier techniques to R=0.036, Rw=0.022 in space group Pcmn. The cell dimensions change upon dehydration from a=9.792 (2), b= 13.644 (3), c=9.629 (2) A, V= 1286.5 (3) A3 to a=9.368 [2), b= 12.808 (3), e= 9.550 (2) ,~, V= 1145-8 (3) ,3. The 11% reduction of volume results mainly from removal of water between the silicate layers which lie perpendicular to b. The layers consist of four-and eightmembered rings of SiO4 tetrahedra linked so that the sequence of tetrahedra around the eight-rings is UUUUDDDD (U up, D down). The layers are connected vertically (b direction) by V 4+ cations in a square pyramidal coordination to give an infinite silicate-vanadyl complex. Replacement of each VOs group by two bridging oxygens gives the framework of the zeolite gismondine which has the same layers of four-and eight-membered rings but displays a fully expanded configuration. The Ca cations and the water molecules reside in the channels formed by the eight-rings and between the SiOz layers. At 220°C only one water molecule per Ca ion occurs in the structure. Removal of this last water molecule probably corresponds to the breakdown of the structure observed at ~400~'C. The vanadyl groups were found to have two orientations with the unshared oxygens pointing in opposite directions with a ratio of 10: 1. Therefore there are two ideal structural models of cavansite with an infinite number of disordered intermediates.

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“…Unit-cell parameters [phillipsite: a=9.865 (2), b= 14.300 (4), c= 8.668 (2) A, fl= 124.20 (3)°; harmotome: a--9.879 (2), b=14.139 (2), c=8.693 (2) A, fl= 124.81 (1) °] were determined by the least-squares refinement of 30 high 20 values (Burnham, 1962). The 20 values were measured on a Picker-FACS-1 diffractometer at room temperature and determined by averaging 4 half-height-peak settings (plus and minus 20).…”

Section: Methodsmentioning

confidence: 99%

Zeolites of the phillipsite family. Refinement of the crystal structures of phillipsite and harmotome

Rinaldi¹,

Pluth²,

Smith³

1974

Acta Crystallogr Sect B

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Phillipsite (K~2Ca~t.sNa~0.4Al~sSi~a0032.12H20) and harmotome (Ba~2Ca~0.sAl~sSi~11032.12H20) were found to be isostructural with the same cationic sites and water-molecule distribution within an almost identical framework. Both minerals crystallize in the monoclinic system (P21 or P2Jm) with respective cell dimensions: a= 9"865 (2), b = 14"300 (4), c= 8"668 (2)/~,//= 124"20 (3) °, and a = 9-879 (2), b= 14-139 (2), c=8.693 (2) A, fl= 124.81 (1) °. Intensity data from a 4-circle diffractometer were refined by least-squares and Fourier techniques to respective R's of 0-063 and 0.047. The aluminosilicate framework is topologically identical to that found by earlier workers. No evidence for Si,Al ordering was found. All cations and water molecules were unequivocally located although some water molecules showed large atomic displacements. There are two cation sites: one, fully occupied by K in phillipsite and Ba in harmotome, is surrounded by eight framework oxygens and four water molecules. The other site is partially occupied by Ca and Na in a distorted octahedral coordination with two framework oxygens and four water molecules. Two of the water molecules associated with Ca showed large atomic displacements consistent with partial occupancy of the Ca site. Refinement of harmotome in P21 was unsuccessful and the structure is best described in P2x/m.

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G. W. Leibniz: Monadology

Cited by 7 publications

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Micro‐Raman spectroscopy of natural members along CuSbS₂–CuSbSe₂ join

Micro‐Raman spectroscopy of natural members along CuSbS₂–CuSbSe₂ join

Crystal structure of cavansite dehydrated at 220°C

Zeolites of the phillipsite family. Refinement of the crystal structures of phillipsite and harmotome

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G. W. Leibniz: Monadology

Cited by 7 publications

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Micro‐Raman spectroscopy of natural members along CuSbS2–CuSbSe2 join

Micro‐Raman spectroscopy of natural members along CuSbS2–CuSbSe2 join

Crystal structure of cavansite dehydrated at 220°C

Zeolites of the phillipsite family. Refinement of the crystal structures of phillipsite and harmotome

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Micro‐Raman spectroscopy of natural members along CuSbS₂–CuSbSe₂ join

Micro‐Raman spectroscopy of natural members along CuSbS₂–CuSbSe₂ join