Crystal structure and compressibility of a two-layer polytype of pseudowollastonite (CaSiO<sub>3</sub>)

Yang, Hexiong; Prewitt, C. T.

doi:10.2138/am-1999-11-1217

Cited by 35 publications

(16 citation statements)

References 21 publications

(36 reference statements)

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“…Insights into the topology of CaMgSi 2 O 6 liquid at low pressure may be obtained by reviewing the 1‐bar volume of fusion data not only for diopside, but also for enstatite (Mg 2 Si 2 O 6 ) and pseudowollastontite (Ca 2 Si 2 O 6 ). In Figure 10, the molar volumes of crystalline enstatite, diopside, and pseudowollastonite (calculated from the data of Hugh‐Jones [1997], Richet et al [1998], Yang and Prewitt [1999], and Tribaudino et al [2000]) are shown relative to the molar volumes of liquid Mg 2 Si 2 O 6 , CaMgSi 2 O 6 , and Ca 2 Si 2 O 6 (calculated from Lange [1997]), all at 1 bar and 1670 K. The results show that the volume of fusion for pseudowollastonite (2.7%) is substantially smaller relative to those for enstatite (17.8%) and diopside (16.7%). The difference in magnitude is due entirely to the much larger crystalline volume of the pyroxenoid, pseudowollastonite, relative to those for the pyroxenes, enstatite, and diopside.…”

Section: Density Of Liquid Camgsi2o6 Versus Crystalline Diopside Withmentioning

confidence: 99%

“…The molar volumes of crystalline enstatite, diopside, and pseudowollastonite at 1670 K and 1 bar (shown in open triangles and calculated from Hugh‐Jones [1997], Richet et al [1998], Yang and Prewitt [1999], and Tribaudino et al [2000]). The molar volumes of Mg 2 Si 2 O 6 , CaMgSi 2 O 6 , and Ca 2 Si 2 O 6 liquids at 1670 K and 1 bar are shown in solid triangles and are calculated from Lange [1997].…”

Section: Density Of Liquid Camgsi2o6 Versus Crystalline Diopside Withmentioning

confidence: 99%

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New acoustic velocity measurements on CaO‐MgO‐Al₂O₃‐SiO₂ liquids: Reevaluation of the volume and compressibility of CaMgSi₂O₆‐CaAl₂Si₂O₈ liquids to 25 GPa

Ai¹,

Lange²

2008

J. Geophys. Res.

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[1] Relaxed sound speed measurements on 12 liquids in the CaO-MgO-Al 2 O 3 -SiO 2 (CMAS) system have been performed from 1410 to 1620°C at 1 bar with a frequency sweep acoustic interferometer. In all liquids, the sound speeds either decrease or remain constant with increasing temperature. These data are combined with those in the literature to calibrate models for b T and (@V/@P) T as a function of composition and temperature for CMAS liquids. CaO is the only oxide component that contributes to the temperature dependence of compressibility. The new compressibility models permit the bulk modulus (K T,0 ) of CaMgSi 2 O 6 (Di), CaAl 2 Si 2 O 8 (An), and the Di 64 -An 36 eutectic liquid to be directly obtained. These results are used to uniquely constrain values for the pressure dependence of the bulk modulus (K 0 0 = dK 0 /dP) in a third-order Birch-Murnaghan equation of state (EOS) for these three liquids from shock wave data in the literature. The revised K 0 0 value is 6.8 (versus 6.9) for CaMgSi 2 O 6 liquid, 4.7 (versus 5.3) for CaAl 2 Si 2 O 8 liquid, and 5.6 (versus 4.85) for Di 64 -An 36 liquid. Information on both K T,0 and K 0 0 allows the density and compressibility for each of these three liquids to be calculated as a function of pressure to 25 GPa. Both the molar volume and isothermal compressibility of CaMgSi 2 O 6 -CaAl 2 Si 2 O 8 liquids mix ideally between 0 and 25 GPa. The dominant mechanism of compression at low pressure (0-5 GPa) for all three liquids (CaMgSi 2 O 6 , CaAl 2 Si 2 O 8 , and the Di 64 -An 36 eutectic) is topological, whereas gradual Al/Si coordination change plays an increasingly important role at higher pressure as topological mechanisms of compression are diminished.

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Section: Density Of Liquid Camgsi2o6 Versus Crystalline Diopside Withmentioning

confidence: 99%

Section: Density Of Liquid Camgsi2o6 Versus Crystalline Diopside Withmentioning

confidence: 99%

New acoustic velocity measurements on CaO‐MgO‐Al₂O₃‐SiO₂ liquids: Reevaluation of the volume and compressibility of CaMgSi₂O₆‐CaAl₂Si₂O₈ liquids to 25 GPa

Ai¹,

Lange²

2008

J. Geophys. Res.

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“…It is still unknown whether the corner-sharing perovskite-structured silicates could provide a lattice site large enough to accommodate the Sr 2+ cation. SrSiO 3 crystallizes in a monoclinic structure (C2/c, Z = 12) at ambient conditions (Nishi 1997a) isotypic to the hightemperature modification of CaSiO 3 (pseudowollastonite) (Yang and Prewitt 1999) and SrGeO 3 (Nishi 1997b). The typical features of the pseudowollastonite-type SrSiO 3 are alternate layers of ternary (Si 3 O 9 ) tetrahedral rings and close-packed Sr atoms stacked along the [001] direction forming a six-layer-repeated structure (Nishi 1997a).…”

Section: Introductionmentioning

confidence: 99%

Cubic perovskite polymorph of strontium metasilicate at high pressures

Xiao

Zhou

Liu

et al. 2013

American Mineralogist

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By using a diamond-anvil cell (DAC) with laser heating technology, a cubic perovskite polymorph of SrSiO 3 has been synthesized at ∼38 GPa and 1500-2000 K for the first time. The P-V data of this new phase give ambient temperate elastic constants of V 0 = 49.18(5) Å 3 , K 0 = 211(3) GPa, respectively, when they are fitted against the Birch-Murnaghan equation of state with a fixed K 0 ′ at 4. On decompression, the SrSiO 3 cubic perovskite phase becomes unstable at ∼6.2 GPa and disappears completely at ∼4.7 GPa. The transformed product can be considered as an amorphous phase with a minor amount of small sized crystals in the amorphous matrix. First principle calculations predicted structural properties of both the cubic and the six-layer-repeated hexagonal perovskite polymorphs of SrSiO 3 in good agreement with experimental results. The experimental and theoretical results indicate that the larger Sr 2+ cation can substitute the Ca 2+ cation and enter into the lattice of the cubic perovskite phase of CaSiO 3 at lower mantle conditions with only a small lattice strain. These results indicate that Sr can be hosted in cubic perovskite CaSiO 3 found as inclusions in diamonds originating from the lower mantle.

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“…6), with three O-O interatomic distances close to 2.9 Å and O-O-O angles close to 60 . Such a threefold ring has been encountered as Si 3 O 9 rings in silicates of the related wollastonite CaSiO 3 (Yang & Prewitt, 1999;Joswig et al, 2003) and Ge 3 O 9 rings in PbGe 4 O 9 (Bush & Stephanovitch, 2002) and Sb 2 Ge 3 O 9 (Ke et al, 2002). In the latter the Ge 3 O 9 rings are connected by pairs to trigonal pyramids SbO 3 .…”

Section: The Ca 6 Al 12 O 24 Frameworkmentioning

confidence: 99%

The modulated structure of the calcium aluminate Ca₆(AlO₂)₁₂·Bi₂O₃

Pérez

Malo

Hervieu

2010

Acta Crystallogr Sect B

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Bismuth calcium aluminate, Bi(2)Ca(6)Al(12)O(27), has been prepared as a ceramic and a single crystal. Analysis of reciprocal space using both electron and X-ray diffraction show an R-centred hexagonal unit cell: a = b = 17.3892 (4), c = 6.986 (1) Å. Additional weak reflections are observed; they require the introduction of a modulation wavevector q = 0.0453 (2)c* for indexing. The modulated structure has been solved using the superspace formalism [superspace group X3(00γ)0]. A framework of corner-sharing AlO(4) tetrahedra forms corrugated sixfold rings and uncommon triple rings. The Ca(2+) cations exhibit an eightfold coordination sphere; edge-sharing CaO(8) polyhedra form intertwinned zigzagging rows along c creating a three-dimensional net. Bi atoms are located in large hexagonal tunnels parallel to c and form Bi(2)O(3) pairs, which adopt a trigonal bipyramidal configuration. The 6s(2) lone-electron pairs (Lp) point along c, in the opposite direction to the three Bi-O strong bonds to form two BiO(3)Lp tetrahedra with a common base. Different orientations of the Bi(2)O(3)Lp(2) pairs, rotated by 60° around c, are observed. Their stacking modes in each of the hexagonal tunnels are described. The sequence of the stacking varies along c in each of the tunnels.

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Crystal structure and compressibility of a two-layer polytype of pseudowollastonite (CaSiO₃)

Cited by 35 publications

References 21 publications

New acoustic velocity measurements on CaO‐MgO‐Al₂O₃‐SiO₂ liquids: Reevaluation of the volume and compressibility of CaMgSi₂O₆‐CaAl₂Si₂O₈ liquids to 25 GPa

New acoustic velocity measurements on CaO‐MgO‐Al₂O₃‐SiO₂ liquids: Reevaluation of the volume and compressibility of CaMgSi₂O₆‐CaAl₂Si₂O₈ liquids to 25 GPa

Cubic perovskite polymorph of strontium metasilicate at high pressures

The modulated structure of the calcium aluminate Ca₆(AlO₂)₁₂·Bi₂O₃

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Crystal structure and compressibility of a two-layer polytype of pseudowollastonite (CaSiO3)

Cited by 35 publications

References 21 publications

New acoustic velocity measurements on CaO‐MgO‐Al2O3‐SiO2 liquids: Reevaluation of the volume and compressibility of CaMgSi2O6‐CaAl2Si2O8 liquids to 25 GPa

New acoustic velocity measurements on CaO‐MgO‐Al2O3‐SiO2 liquids: Reevaluation of the volume and compressibility of CaMgSi2O6‐CaAl2Si2O8 liquids to 25 GPa

Cubic perovskite polymorph of strontium metasilicate at high pressures

The modulated structure of the calcium aluminate Ca6(AlO2)12·Bi2O3

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Crystal structure and compressibility of a two-layer polytype of pseudowollastonite (CaSiO₃)

New acoustic velocity measurements on CaO‐MgO‐Al₂O₃‐SiO₂ liquids: Reevaluation of the volume and compressibility of CaMgSi₂O₆‐CaAl₂Si₂O₈ liquids to 25 GPa

New acoustic velocity measurements on CaO‐MgO‐Al₂O₃‐SiO₂ liquids: Reevaluation of the volume and compressibility of CaMgSi₂O₆‐CaAl₂Si₂O₈ liquids to 25 GPa

The modulated structure of the calcium aluminate Ca₆(AlO₂)₁₂·Bi₂O₃