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.
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 -