Ab initio investigations of TlI-type compounds under high pressure
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Daniel Becker
Abstract
In this work, we present a theoretical study (based on DFT-calculations) in a wide pressure range of the structural and electronic properties and the stability of compounds crystallising in a TlI- or CrB-type structure. Both structure types have the characteristic structural feature of zigzag chains with unusual short homonuclear distances. The main focus of this study is to elucidate the nature of bonding within these zigzag chains at ambient and elevated pressure. For this purpose we discuss the evolution of the distances within the zigzag chains with pressure, the transition pressure of the phase transition to a CsCl-type arrangement (high-pressure phase) and compressibilities of the low- and high-pressure phases. For a better understanding of the structure and bonding, the band structures of these compounds are evaluated. The calculations are complemented by an orbital analysis using the crystal orbital Hamilton population (COHP) and an analysis of the electronic density topology with the electron localisation function (ELF). Our study indicates that there is a bonding electron pair in compounds crystallising in the CrB-type structure and that the nature of the electron pair does not change significantly at elevated pressure up to the phase transition. However, the “character” of the additional electron pair in the In-monohalides (TlI-type structure) changes with increasing pressure from nonbonding to bonding. The phase transition to a CsCl- type structure implies a fundamental change to nonbonding stereochemically inert electron pairs for all compounds.
© 2004 Oldenbourg Wissenschaftsverlag GmbH
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- Polymorphic forms of Rb2Te: in-situ high-pressure DAC X-ray diffraction investigations and structure modelling with CASTEP
- Electronic structure and bonding in antimony and its high pressure phases
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Articles in the same Issue
- Editorial: High-Pressure Crystallography and Synthesis
- New pressure cell for single-crystal X-ray investigations on diffractometers with area detectors
- High-pressure and high-temperature powder diffraction on molybdenum diphosphide, MoP2
- The effects of pressure, temperature and composition on the crystal structures of α-quartz homeotypes
- High-pressure behavior of sillimanite and kyanite: Compressibility, decomposition and indications of a new high-pressure phase
- Multianvil high-pressure / high-temperature synthesis in solid state chemistry
- Putting the squeeze on NaCl: modelling and simulation of the pressure driven B1-B2 phase transition
- Mechanism of the pressure induced reconstructive transformation of KCl from the NaCl type to the CsCl type structure
- Ab initio investigations of TlI-type compounds under high pressure
- Polymorphic forms of Rb2Te: in-situ high-pressure DAC X-ray diffraction investigations and structure modelling with CASTEP
- Electronic structure and bonding in antimony and its high pressure phases
- Metallic high-pressure modifications of main group elements
