Atomic thermal parameters and thermodynamic functions for chrysoberyl (BeAl<sub>2</sub>O<sub>4</sub>) from vibrational spectra and transfer of empirical force fields

Pilati, Tullio; Demartin, Francesco; Cariati, F.; Bruni, Silvia; Gramaccioli, C. M.

doi:10.1107/s0108768192011601

Cited by 17 publications

(7 citation statements)

References 14 publications

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“…BeAl 2 O 4 (crysoberyl; Pilati et al, 1993) belongs to the olivine-group structures. In it, the Al atoms are octahedrally coordinated and the Be atoms are at the center of the O 4 tetrahedra.…”

Section: Alkaline-earth Aluminatesmentioning

confidence: 99%

The Zintl–Klemm concept applied to cations in oxides. I. The structures of ternary aluminates

Santamarı́a-Pérez¹,

Vegas²

2003

Acta Crystallogr B Struct Sci

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The structures of 94 ternary aluminates are reinterpreted on the basis of the Zintl±Klemm concept and Pearson's generalized octet rule. In aluminates of highly electropositive metals such as alkali, alkaline-earth and rare-earth metals, the Al atoms form three-dimensional skeleta which can be interpreted as if the Al atoms were behaving as Zintl polyanions, adopting the structure of either main-group elements or Zintl polyanions showing the same connectivity. The O atoms are then located close to both the hypothetical two-electron bonds and the lone pairs, giving rise to a tetrahedral coordination. When more electronegative elements, such as W or Si, are present in the compound, the electron transfer towards the Al atoms does not take place. In this case, aluminium behaves as a base, transferring its electrons to the more electronegative atoms and the coordination sphere of aluminium becomes octahedral. In some compounds the Al atoms clearly show amphoteric character so that some Al atoms act as donors (bases) and hence are octahedrally coordinated, whereas others behave as acceptors (acids), adopting a tetrahedral coordination. From this it is concluded that the coordination sphere of aluminium is not a function of the ionic radius of the Al 3+ cations, but it depends on the nature of the other cations accompanying them in the structure. The networks formed by these aluminates are, in many instances, similar to those of the binary oxides of the main-group elements. For this reason, a systematic survey of these oxides is also reported. Compounds such as stuffed cristobalites and trydimites and also perovskites are examples of this new interpretation. Perovskites are then reinterpreted as a stuffed pseudo-TeO 3 structure. Other families of compounds such as silicates and phosphates are susceptible to a similar interpretation. This study provides additional examples of how cations recognize themselves in spite of being embedded in an oxygen matrix.

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Section: Alkaline-earth Aluminatesmentioning

confidence: 99%

The Zintl–Klemm concept applied to cations in oxides. I. The structures of ternary aluminates

Santamarı́a-Pérez¹,

Vegas²

2003

Acta Crystallogr B Struct Sci

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“…Following our interest in the field, which started from molecular crystals, we have tried to extend our Born−von Karman harmonic lattice-dynamical calculations to minerals, initially considering some oxides such as corundum (α-Al 2 O 3 ), quartz (α-SiO 2 ), coesite (SiO 2 ), chrysoberyl (Al 2 BeO 4 ), and bromellite (BeO) and then also silicates such as the olivine group, garnets, andalusite (Al 2 OSiO 4 ), kyanite (Al 2 OSiO 4 ), diopside (CaMgSi 2 O 6 ), beryl (Be 3 Al 2 Si 6 O 18 ) and some carbonates such as calcite and aragonite (α- and β-CaCO 3 ), magnesite (MgCO 3 ), and dolomite [CaMg(CO 3 ) 2 ]. − In all these cases, our calculations were extended to the whole Brillouin zone; for the sake of simplicity, a rigid-ion (or rigid-atom) model was used. In this model, the electron cloud of each ion (or atom, in general) is assumed not to be deformed (or displaced from the nucleus) during motion.…”

Section: Introductionmentioning

confidence: 99%

Single-Crystal Vibrational Spectrum of Phenakite, Be₂SiO₄, and Its Interpretation Using a Transferable Empirical Force Field

Pilati

Gramaccioli²,

Pezzotta³

et al. 1998

J. Phys. Chem. A

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Using an oriented single crystal, Raman and infrared vibrational spectra have been measured for phenakite, Be2SiO4. The results have been interpreted on the grounds of Born−von Karman rigid-ion lattice-dynamical calculations, using empirical potentials derived from fitting the vibrational frequencies of a group of silicates, carbonates, and oxides, not including the substance under study. The very good agreement of our calculations with experimental data of independent origin and nature confirms the transferability of empirical potentials, and also their advantageous use for interpreting and reproducing the vibrational spectra of silicates and oxides in general.

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“…calcite, magnesite, dolomite and aragonite) plus those of quartz, a few silicates such as some members of the olivine group (forsterite Mg 2 SiO 4 and monticellite CaMgSiO 4 ), andalusite Al 2 SiO 5 , diopside CaMgSi 2 O 6 and some oxides containing Al or Be, such as corundum, chrysoberyl and bromellite. Most of these data are Raman-and IR-active frequencies obtained by different authors (Hellwege et al, 1970;Cowley & Pant, 1973;Frech et al, 1980; for additional details, and reference to the sources for data on noncarbonates, see Pilati, Demartin, Cariati et al, 1993, Pilati et al, 1990c, 1994, 1995. The lowest branches of the phonon dispersion curves were included when available, as for calcite, quartz, forsterite and andalusite.…”

Section: Analysis Of Results and Discussionmentioning

confidence: 99%

“…Such substances are well represented by many classic examples of minerals, whose structures are relatively simple and which have been extensively investigated. We initially considered some oxide minerals such as corundum ( -Al (Pilati et al, 1990c;Pilati, Demartin, Cariati et al, 1993;Pilati et al, , 1994Pilati et al, , 1995Pilati et al, , 1996aPilati et al, ,b, 1997a. Although for the sake of simplicity in all our calculations a rigid-ion (or rigidatom) model was used, our results were successful.…”

Section: Introductionmentioning

confidence: 99%

Lattice-Dynamical Estimation of Atomic Displacement Parameters in Carbonates: Calcite and Aragonite CaCO₃, Dolomite CaMg(CO₃)₂ and Magnesite MgCO₃

Pilati¹,

Demartin²,

Gramaccioli³

1998

Acta Crystallogr B Struct Sci

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Using crystallographic information and empirical potentials derived from ®tting the vibrational frequencies of all the substances under study, together with those of a group of silicates and oxides, a Born±von Karman rigidion lattice-dynamical model has been applied to the whole Brillouin zone in calcite, aragonite ( -andCaCO 3 , respectively), magnesite (MgCO 3 ) and dolomite [CaMg(CO 3 ) 2 ]. The Raman and IR spectra are satisfactorily reproduced and interpreted by these calculations; there is also very good agreement with atomic anisotropic displacement parameters (a.d.p.'s) derived from accurate crystal structure re®nement by various authors and with the experimental values of thermodynamic functions over a wide range of temperatures. On these vibrational grounds, the stability of calcite with respect to aragonite at high temperature can be accounted for.

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Atomic thermal parameters and thermodynamic functions for chrysoberyl (BeAl₂O₄) from vibrational spectra and transfer of empirical force fields

Cited by 17 publications

References 14 publications

The Zintl–Klemm concept applied to cations in oxides. I. The structures of ternary aluminates

The Zintl–Klemm concept applied to cations in oxides. I. The structures of ternary aluminates

Single-Crystal Vibrational Spectrum of Phenakite, Be₂SiO₄, and Its Interpretation Using a Transferable Empirical Force Field

Lattice-Dynamical Estimation of Atomic Displacement Parameters in Carbonates: Calcite and Aragonite CaCO₃, Dolomite CaMg(CO₃)₂ and Magnesite MgCO₃

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Atomic thermal parameters and thermodynamic functions for chrysoberyl (BeAl2O4) from vibrational spectra and transfer of empirical force fields

Cited by 17 publications

References 14 publications

The Zintl–Klemm concept applied to cations in oxides. I. The structures of ternary aluminates

The Zintl–Klemm concept applied to cations in oxides. I. The structures of ternary aluminates

Single-Crystal Vibrational Spectrum of Phenakite, Be2SiO4, and Its Interpretation Using a Transferable Empirical Force Field

Lattice-Dynamical Estimation of Atomic Displacement Parameters in Carbonates: Calcite and Aragonite CaCO3, Dolomite CaMg(CO3)2 and Magnesite MgCO3

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Atomic thermal parameters and thermodynamic functions for chrysoberyl (BeAl₂O₄) from vibrational spectra and transfer of empirical force fields

Single-Crystal Vibrational Spectrum of Phenakite, Be₂SiO₄, and Its Interpretation Using a Transferable Empirical Force Field

Lattice-Dynamical Estimation of Atomic Displacement Parameters in Carbonates: Calcite and Aragonite CaCO₃, Dolomite CaMg(CO₃)₂ and Magnesite MgCO₃