Über eine Hochdruckmodifikation des SrAl<sub>2</sub> / On a High Pressure Modification of SrAl<sub>2</sub>

Cordier, G.; Czech, E.; Schäfer, Herbert

doi:10.1515/znb-1982-1115

Cited by 34 publications

(16 citation statements)

References 1 publication

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“…In this line, Gingl and coworkers claim that the new SrAl 2 H 2 phase is a Zintl‐type hydride 7. This compound was obtained by exposing the intermetallic 8 SrAl 2 to hydrogen gas. The SrAl 2 host crystallizes in the orthorhombic structure below 1423 K and 60 kbar.…”

Section: Introductionmentioning

confidence: 99%

Bonding properties of the new zintl‐phase hydrides

Orgaz

Aburto

2004

Int J of Quantum Chemistry

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ABSTRACT:We investigated the electronic structure of three recently discovered Zintl-phase hydrides: SrAl 2 H 2 , Ca 3 SnH 2 , and Ca 5 Sn 3 H. The energy bands and the total and partial densities of states were computed by means of the full-potential linearized augmented-plane-wave method. We found the SrAl 2 H 2 and Ca 5 Sn 3 H hydrides are metallic and Ca 3 SnH 2 is a small-gap semiconductor. We analyzed the chemical bonding features of this series of compounds.

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Section: Introductionmentioning

confidence: 99%

Bonding properties of the new zintl‐phase hydrides

Orgaz

Aburto

2004

Int J of Quantum Chemistry

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“…17. Although no phase of the Group 14 elements is known to have this structure, it is identical to that adopted by the Al (Ψ -Si) atoms in the Zintl phase SrAl 2 [89]. The O atoms are located near to the centres of all the Al -Si bonds producing the tetrahedral coordination of the Al(Si) atoms.…”

Section: The Sral -Type Skeletonmentioning

confidence: 88%

The Zintl–Klemm Concept Applied to Cations in Oxides. II. The Structures of Silicates

Pérez¹,

Vegas²,

Liebau³

Semiconductor Nanocrystals and Silicate Nanoparticles

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The structures of ternary and quaternary silicates are revisited on the basis of the Zintl-Klemm concept and the Pearson's generalised octet rule. The three-dimensional skeletons formed by the Si atoms can be interpreted as if the Si atoms were behaving as 122 D. Santamaría-Pérez et al. 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. In some silicates, the Si atoms clearly show an amphoteric character so that some Si atoms act as donors (bases) adopting an octahedral coordination, whereas others behave as acceptors (acid), adopting a tetrahedral coordination. Although the octahedral coordination seems to be favoured by the application of pressure, the results reported here indicate that the coordination sphere of silicon is not a function of the assumed ionic radius of the Si 4+ cations but it depends on the nature of the other cations accompanying them in the structure.

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“…CeCu 2 ! MgCu 2 described above for both SrGa 2 (Iandelli, 1955) and SrAl 2 (Cordier et al, 1982) on one hand, and by the Ni 2 In ! MgCu 2 transition occurring in the olivine !…”

Section: The Eutectic Componentsmentioning

confidence: 92%

“…The existence of DyAl x Ga 2 À x is relevant because of its high Al content and also because it is isostructural to SrGa 2 (Iandelli, 1955). Even the binary SrAl 2 compound has not been obtained as AlB 2 -type so far; its ambient pressure structure (CeCu 2 -type) transforms at high pressures into the MgCu 2 -type (Cordier et al, 1982 The underlying idea is that there must be some structural coincidences between the cation sublattices in both phases of the eutectic (the perovskite-like NdAlO 3 and the -aluminalike NdAl 11 O 18 ), on the one hand, and between those phases and the -Al 2 O 3 forming the faceted zones and the substrate, on the other. Next, the cation subarrays of all the oxides involved in the eutectic will be analyzed keeping in mind the structures of the alloys described above.…”

Section: The Alloysmentioning

confidence: 99%

In-situlaser synthesis of Nd–Al–O coatings: the role of sublattice cations in eutectic formation

Francisco

Bea

Vegas³

et al. 2015

Acta Crystallogr Sect B

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# 2015 International Union of Crystallography Neodymium aluminate coatings have been prepared in-situ by the laser zone melting (LZM) method, using a CO 2 SLABtype laser emitting at 10.6 mm. Polycrystalline Al 2 O 3 commercial plates have been used as substrates, and coatings were prepared from the corresponding mixtures of powdered neodymium and aluminium oxides as starting materials. Microstructure, studied by SEM and phase composition, studied by XRD, proved the in-situ formation of a NdAlO 3 / NdAl 11 O 18 eutectic. As a result, a well integrated composite coating was formed. Nanoindentation tests are consistent with excellent integration between coating and substrate. Structural similarities between the eutectic components within the coating, as well as between these and the substrate, are consistent with the crystallographic concepts proposed by Vegas (Ramos-Gallardo & Vegas, 1997), where cation subarrays play an important role governing metal oxide structures. These structure sublattices are suggested as the driving force behind eutectic oxide formation.

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Über eine Hochdruckmodifikation des SrAl₂ / On a High Pressure Modification of SrAl₂

Abstract: SrAl2, forming at standard conditions the KHg2 structure type, transforms at ~60 kbar and 1050 °C to a high pressure modification with the MgCu2 structure (a = 832.5(5) pm).

Cited by 34 publications

References 1 publication

Bonding properties of the new zintl‐phase hydrides

Bonding properties of the new zintl‐phase hydrides

The Zintl–Klemm Concept Applied to Cations in Oxides. II. The Structures of Silicates

In-situlaser synthesis of Nd–Al–O coatings: the role of sublattice cations in eutectic formation

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Über eine Hochdruckmodifikation des SrAl2 / On a High Pressure Modification of SrAl2

Abstract: SrAl2, forming at standard conditions the KHg2 structure type, transforms at ~60 kbar and 1050 °C to a high pressure modification with the MgCu2 structure (a = 832.5(5) pm).

Cited by 34 publications

References 1 publication

Bonding properties of the new zintl‐phase hydrides

Bonding properties of the new zintl‐phase hydrides

The Zintl–Klemm Concept Applied to Cations in Oxides. II. The Structures of Silicates

In-situlaser synthesis of Nd–Al–O coatings: the role of sublattice cations in eutectic formation

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Über eine Hochdruckmodifikation des SrAl₂ / On a High Pressure Modification of SrAl₂