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Complete Titanium Substitution by Boron in a Tetragonal Prism: Exploring the Complex Boride Series Ti3-xRu5-yIryB2+x (0 ⩽ x ⩽ 1 and 1 < y < 3) by Experiment and Theory.
- Source :
-
Inorganic Chemistry . 4/18/2011, Vol. 50 Issue 8, p3332-3341. 10p. - Publication Year :
- 2011
-
Abstract
- Polycrystalline samples and single crystals of four members of the new complex boride series Ti3−xRu5−yIryB2+x (0 ≤ x ≤ 1 and 1 < y < 3) were synthesized by arc-melting the elements in a water-cooled copper crucible under an argon atmosphere. The new silvery phases were structurally characterized by powder and single-crystal X-ray diffraction as well as energy- and wavelength-dispersive X-ray spectroscopy analyses. They crystallize with the tetragonal Ti3Co5B2 structure type in space group P4/mbm (No. 127). Tetragonal prisms of Ru/Ir atoms are filled with titanium in the boron-poorest phase (Ti3Ru2.9Ir2.1B2). Gradual substitution of titanium by boron then results in the successive filling of this site by a Ti/B mixture en route to the complete boron occupation, leading to the boron-richest phase (Ti2Ru2.8Ir2.2B3). Furthermore, both ruthenium and iridium share two sites in these structures, but a clear Ru/Ir site preference is found. First-principles density functional theory calculations (Vienna ab initio simulation package) on appropriate structural models (using a supercell approach) have provided more evidence on the stability of the boron-richest and -poorest phases, and the calculated lattice parameters corroborate very well with the experimentally found ones. Linear muffin-tin orbital atomic sphere approximation calculations further supported these findings through crystal orbital Hamilton population bonding analyses, which also show that the Ru/Ir−B and Ru/Ir−Ti heteroatomic interactions are mainly responsible for the structural stability of these compounds. Furthermore, some stable and unstable phases of this complex series could be predicted using the rigid-band model. According to the density of states analyses, all phases should be metallic conductors, as was expected from these metal-rich borides. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00201669
- Volume :
- 50
- Issue :
- 8
- Database :
- Academic Search Index
- Journal :
- Inorganic Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 66858188
- Full Text :
- https://doi.org/10.1021/ic102148x