Heat capacity of wadeite-type K 2 Si 4 O 9 and the pressure-induced stable decomposition of K-feldspar

Faßhauer, Detlef W.; Wunder, Bernd; Chatterjee, Niranjan D.; Höhne, G.W.H.

doi:10.1007/s004100050389

Cited by 28 publications

(16 citation statements)

References 23 publications

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“…Many experiments have been devoted to the phase stability, thermal behavior, and structural evolution at high-and lowtemperature of kalsilite, which appear to be strongly controlled by the Na content (Tuttle and Smith 1958;Sahama 1962aSahama , 1962bDollase and Freeborn 1977;Gregorkiewitz and Schäfer 1980;Kawahara 1982, 1984; Henderson and Taylor * E-mail: diego.gatta@unimi.it , 1988Abbott 1984;Merlino 1984;Kawahara et al 1987;Roux 1993, 1999;Xu and Veblen 1996;Capobianco and Carpenter 1989;Carpenter and Cellai 1996;Fasshauer et al 1998;Cellai et al 1999;Hovis and Crelling 2000;Hovis et al 2003Hovis et al , 2006Hovis et al , 2009Gatta et al 2010a). In particular, Cellai et al (1997) reported the crystal structure of an essentially Na-free metamorphic kalsilite (i.e., K/Na molar ratio ~350) from Punalur (Kerala district in southern India).…”

Section: Introductionmentioning

confidence: 99%

Phase stability, elastic behavior, and pressure-induced structural evolution of kalsilite: A ceramic material and high-T/high-P mineral

Gatta

Angel

Zhao

et al. 2011

American Mineralogist

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The phase stability, elastic behavior, and pressure-induced structural evolution of a natural metamorphic kalsilite (ideal formula KAlSiO 4 ) from Punalur (Kerala district in southern India), with P31c symmetry and a K/Na molar ratio of ~350, has been investigated by in situ X-ray single-crystal diffraction up to ~7 GPa with a diamond-anvil cell under hydrostatic conditions. At high-pressure, a previously unreported iso-symmetric first-order phase transition occurs at ~3.5 GPa. The volume compression of the two phases is described by third-order Birch-Murnaghan equations-of-state: V 0 = 201.02(1) Å 3 , K T0 = 59.7(5) GPa, K′ = 3.5(3) for the low-P polymorph, and V 0 = 200.1(13) Å 3 , K T0 = 44(8) GPa, K′ = 6.4(20) for the high-P polymorph. The pressure-induced structural evolution in kalsilite up to 7 GPa appears to be completely reversible. The compression of both phases involves tetrahedral rotations around [0001], which close up the channels within the framework. In addition, compression of the low-pressure phase involves tilting of the tetrahedra. The major structural change at the phase transition is an increase in the tilting of the tetrahedra, but with a reversion of the tetrahedral rotations to the value found at ambient conditions. This behavior is in distinct contrast to that of nepheline, which has a tetrahedral framework of the same topology.

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Section: Introductionmentioning

confidence: 99%

Phase stability, elastic behavior, and pressure-induced structural evolution of kalsilite: A ceramic material and high-T/high-P mineral

Gatta

Angel

Zhao

et al. 2011

American Mineralogist

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“…The HP behavior of a synthetic leucite was investigated by means of synchrotron X-ray powder diffraction up to 5.1 GPa by Fasshauer et al (1998). The authors reported only the P-V data and no structural refinement at high pressure was performed.…”

Section: Introductionmentioning

confidence: 99%

“…No phase transition was found within the P range investigated. Fasshauer et al (1998) calculated the bulk modulus of leucite and its P-derivative using a Murnaghan Equation-of-State (EoS, Murnaghan 1937), obtaining K 0 = 45 GPa and K′ = 5.7. However, the P-V data are significantly scattered and do not provide clear evidence of phase-stability of the tetragonal leucite within the pressure range investigated.…”

Section: Introductionmentioning

confidence: 99%

Leucite at high pressure: Elastic behavior, phase stability, and petrological implications

Gatta

Rotiroti

Ballaran

et al. 2008

American Mineralogist

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Elastic and structural behavior of a natural tetragonal leucite from the volcanic Lazium district (Italy) were investigated at high pressure by in situ single-crystal X-ray diffraction with a diamond anvil cell under hydrostatic conditions. A first-order phase transition, never reported in the literature, was observed at P = 2.4 ± 0.2 GPa from tetragonal (I4 1 /a) to triclinic symmetry (analysis of diffraction intensities suggests the space group P1), accompanied by a drastic increase in density of about 4.7%. The transition pressure was bracketed by several measurements in compression and decompression. No further phase-transition has been observed up to 7 GPa. Fitting a second-order Birch-Murnaghan equation of state (BM-EoS) to the pressure-volume data of the tetragonal polymorph, we obtain K 0 = 41.9(6) GPa and K′ = 4 (fixed). In the case of the triclinic polymorph, a second-order BM-EoS gives K 0 = 33.2(5) GPa. The eulerian finite strain (f e ) vs. normalized stress (F e ) curves were calculated for the low-and high-P polymorphs, providing F e (0) = 42 (1) and F e (0) = 33.2(4) GPa, respectively. The axial bulk modulus values of the tetragonal polymorph, calculated with a linearized BM-EoS, are K 0 (a) = 34.5(5) and K 0 (c) = 78(1) GPa. For the triclinic polymorph, we obtain K 0 (a) = 35.9(5), K 0 (b) = 34.9(7), and K 0 (c) = 35.5(7) GPa. The elastic behavior of the low-P polymorph appears to be more anisotropic than that of the high-P polymorph. The HP-crystal structure evolution of the tetragonal polymorph of leucite was studied on the basis of six structural refinements at different pressures between 0.0001 and 1.8 GPa. The main deformation mechanisms at high-pressure are due to tetrahedral tilting, giving rise to an increase of the ellipticity of the four-and six-membered rings of the tetrahedral framework. The T-O bond distances are practically invariant within the stability field of the tetragonal polymorph. The complex P-induced twinning, due to the tetragonal → triclinic phase-transition, and the low quality of the diffraction data at pressure above the phase-transition, did not allow the refinement of the crystal structure of the triclinic polymorph.

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“…1, the previous set of model parameters predicts the compound K 2 Si 4 O 9 to be unstable below 646 K. Later, Fasshauer et al [20] measured the heat capacity of this compound in the temperature range 195-600 K and no dissociation of the compound K 2 Si 4 O 9 was reported. This discrepancy is also resolved in the new set of model parameters (see Fig.…”

Section: Re-optimization Of the Thermodynamic Model For The System K mentioning

confidence: 96%

“…The expression suggested by Fasshauer et al [20], however, was taken for the c p of K 2 Si 4 O 9 . The latter expression was obtained by fitting the results of the heat capacity measurements in the temperature range 195-600 K with the function recommended by Berman and Brown.…”

Section: Re-optimization Of the Thermodynamic Model For The System K mentioning

confidence: 99%

Application of the modified quasichemical model to solutions with strong short-range ordering

Saulov

2007

Journal of Non-Crystalline Solids

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Heat capacity of wadeite-type K 2 Si 4 O 9 and the pressure-induced stable decomposition of K-feldspar

Cited by 28 publications

References 23 publications

Phase stability, elastic behavior, and pressure-induced structural evolution of kalsilite: A ceramic material and high-T/high-P mineral

Phase stability, elastic behavior, and pressure-induced structural evolution of kalsilite: A ceramic material and high-T/high-P mineral

Leucite at high pressure: Elastic behavior, phase stability, and petrological implications

Application of the modified quasichemical model to solutions with strong short-range ordering

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