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Title: BaHg2Tl2. An Unusual Polar Intermetallic Phase with Strong DifferentiationBetween the Neighboring Elements Mercury and Thallium

Abstract

High yields of the novel BaHg2Tl2 are achieved from reactions of the appropriate cast alloys at ~ 400 C. (Isotypic SrHg2Tl2 also exists.) The tetragonal barium structure (P42/mnm, a = 10.417, c = 4.952 ) was refined from both single crystal X-ray and neutron powder diffraction data in order to ensure the atom site assignments although distances and atom site potentials all also supportive of the results. The Hg and Tl network atoms are distinctive in their functions and bonding. Parallel chains of Hg hexagons and of Tl tetrahedra along c are constructed of like polyhedra that share opposed like edges, and these are in turn interconnected by Hg Tl bonds. Overall, Tl Tl bonds per cell exceed Hg Hg by 20:12 although these are ~1:2 in bonding according to the −ICOHP (≈ overlap population) values. Barium is bound within a close 15-atom polyhedron, 12 of which are the more electronegative Hg. LMTO-ASA calculations show that scalar relativistic effects are particularly important for Hg (5d-6s mixing in Hg Hg and Hg Tl bonding), whereas relatively separate (lower) 5d and 6s states of Tl are more important in Tl Tl interactions, appropriate to the 6s2 6p1 ground state for the atom.more » The highest occupied states define a dominantly 6p band, and the phase is metallic and Pauli-like paramagnetic. Binary active metal mercury systems that have been studied theoretically all have distinctly higher electron populations per mercury.« less

Authors:
 [1];  [1];  [2];  [3];  [2]
  1. Ames Laboratory
  2. ORNL
  3. Los Alamos National Laboratory (LANL)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
Work for Others (WFO)
OSTI Identifier:
959445
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 131; Journal Issue: 24; Journal ID: ISSN 0002-7863
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ALLOYS; ATOMS; BARIUM; BONDING; CHAINS; DIFFRACTION; ELECTRONS; GROUND STATES; MERCURY; MONOCRYSTALS; NEUTRONS; SCALARS; THALLIUM

Citation Formats

Dai, Jing-Chao, Gupta, Shalabh, Gourdon, Olivier, Proffen, Th., and Corbett, John D. BaHg2Tl2. An Unusual Polar Intermetallic Phase with Strong DifferentiationBetween the Neighboring Elements Mercury and Thallium. United States: N. p., 2009. Web. doi:10.1021/ja901865d.
Dai, Jing-Chao, Gupta, Shalabh, Gourdon, Olivier, Proffen, Th., & Corbett, John D. BaHg2Tl2. An Unusual Polar Intermetallic Phase with Strong DifferentiationBetween the Neighboring Elements Mercury and Thallium. United States. https://doi.org/10.1021/ja901865d
Dai, Jing-Chao, Gupta, Shalabh, Gourdon, Olivier, Proffen, Th., and Corbett, John D. Thu . "BaHg2Tl2. An Unusual Polar Intermetallic Phase with Strong DifferentiationBetween the Neighboring Elements Mercury and Thallium". United States. https://doi.org/10.1021/ja901865d.
@article{osti_959445,
title = {BaHg2Tl2. An Unusual Polar Intermetallic Phase with Strong DifferentiationBetween the Neighboring Elements Mercury and Thallium},
author = {Dai, Jing-Chao and Gupta, Shalabh and Gourdon, Olivier and Proffen, Th. and Corbett, John D},
abstractNote = {High yields of the novel BaHg2Tl2 are achieved from reactions of the appropriate cast alloys at ~ 400 C. (Isotypic SrHg2Tl2 also exists.) The tetragonal barium structure (P42/mnm, a = 10.417, c = 4.952 ) was refined from both single crystal X-ray and neutron powder diffraction data in order to ensure the atom site assignments although distances and atom site potentials all also supportive of the results. The Hg and Tl network atoms are distinctive in their functions and bonding. Parallel chains of Hg hexagons and of Tl tetrahedra along c are constructed of like polyhedra that share opposed like edges, and these are in turn interconnected by Hg Tl bonds. Overall, Tl Tl bonds per cell exceed Hg Hg by 20:12 although these are ~1:2 in bonding according to the −ICOHP (≈ overlap population) values. Barium is bound within a close 15-atom polyhedron, 12 of which are the more electronegative Hg. LMTO-ASA calculations show that scalar relativistic effects are particularly important for Hg (5d-6s mixing in Hg Hg and Hg Tl bonding), whereas relatively separate (lower) 5d and 6s states of Tl are more important in Tl Tl interactions, appropriate to the 6s2 6p1 ground state for the atom. The highest occupied states define a dominantly 6p band, and the phase is metallic and Pauli-like paramagnetic. Binary active metal mercury systems that have been studied theoretically all have distinctly higher electron populations per mercury.},
doi = {10.1021/ja901865d},
url = {https://www.osti.gov/biblio/959445}, journal = {Journal of the American Chemical Society},
issn = {0002-7863},
number = 24,
volume = 131,
place = {United States},
year = {2009},
month = {1}
}