TY - JOUR
T1 - Metallic Borides, La2Re3B7 and La3Re2B5, Featuring Extensive Boron-Boron Bonding
AU - Bugaris, Daniel E.
AU - Malliakas, Christos D.
AU - Chung, Duck Young
AU - Kanatzidis, Mercouri G.
N1 - Funding Information:
This work was supported as part of the Center for Emergent Superconductivity, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Electron microscopy was accomplished at the Electron Microscopy Center at Argonne National Laboratory, a U.S. Department of Energy Office of Science Laboratory operated under Contract No. DE-AC02- 06CH11357 by UChicago Argonne, LLC.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/2/15
Y1 - 2016/2/15
N2 - La2Re3B7 and La3Re2B5 have been synthesized in single-crystalline form from a molten La/Ni eutectic at 1000 °C in the first example of the flux crystal growth of ternary rare-earth rhenium borides. Both compounds crystallize in their own orthorhombic structure types, with La2Re3B7 (space group Pcca) having lattice parameters a = 7.657(2) Å, b = 6.755(1) Å, and c = 11.617(2) Å, and La3Re2B5 (space group Pmma) having lattice parameters a = 10.809(2) Å, b = 5.287(1) Å, and c = 5.747(1) Å. The compounds possess three-dimensional framework structures that are built up from rhenium boride polyhedra and boron-boron bonding. La3Re2B5 features fairly common B2 dumbbells, whereas La2Re3B7 has unique one-dimensional subunits composed of alternating triangular B3 and trans-B4 zigzag chain fragments. Also observed in La3Re2B5 is an unusual coordination of B by an octahedron of La atoms. Electronic band structure calculations predict that La2Re3B7 is a semimetal, which is observed in the electrical resistivity data as measured on single crystals, with behavior obeying the Bloch-Grüneisen model and a room-temperature resistivity 300 K of ∼375 μ cm. The electronic band structure calculations also suggest that La3Re2B5 is a regular metal.
AB - La2Re3B7 and La3Re2B5 have been synthesized in single-crystalline form from a molten La/Ni eutectic at 1000 °C in the first example of the flux crystal growth of ternary rare-earth rhenium borides. Both compounds crystallize in their own orthorhombic structure types, with La2Re3B7 (space group Pcca) having lattice parameters a = 7.657(2) Å, b = 6.755(1) Å, and c = 11.617(2) Å, and La3Re2B5 (space group Pmma) having lattice parameters a = 10.809(2) Å, b = 5.287(1) Å, and c = 5.747(1) Å. The compounds possess three-dimensional framework structures that are built up from rhenium boride polyhedra and boron-boron bonding. La3Re2B5 features fairly common B2 dumbbells, whereas La2Re3B7 has unique one-dimensional subunits composed of alternating triangular B3 and trans-B4 zigzag chain fragments. Also observed in La3Re2B5 is an unusual coordination of B by an octahedron of La atoms. Electronic band structure calculations predict that La2Re3B7 is a semimetal, which is observed in the electrical resistivity data as measured on single crystals, with behavior obeying the Bloch-Grüneisen model and a room-temperature resistivity 300 K of ∼375 μ cm. The electronic band structure calculations also suggest that La3Re2B5 is a regular metal.
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U2 - 10.1021/acs.inorgchem.5b02599
DO - 10.1021/acs.inorgchem.5b02599
M3 - Article
AN - SCOPUS:84958818892
VL - 55
SP - 1664
EP - 1673
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 4
ER -