Crystal Growth, Structures, and Properties of the Complex Borides, LaOs 2 Al 2 B and La 2 Os 2 AlB 2
Single crystals of two novel quaternary metal borides, LaOs2Al2B and La2Os2AlB2, have been grown from La/Ni eutectic fluxes. LaOs2Al2B crystallizes in tetragonal space group P4/mmm with the CeCr2Si2C-type structure, and lattice parameters a = 4.2075(6) angstrom and c = 5.634(1) angstrom. La2Os2AlB2 exhibits a new crystal structure in monoclinic space group C2/c with lattice parameters a = 16.629(3) angstrom, b = 6.048(1) angstrom, c = 10.393(2) angstrom, and beta = 113.96(3)degrees. Both structures are three-dimensional frameworks with unusual coordination (for solid-state compounds) of the boron atoms by transition metal atoms. The boron atom is square planar in LaOs2Al2B, whereas it exhibits linear and T-shaped geometries in La2Os2AlB2. Electrical resistivity measurements reveal poor metal behavior (rho(30)0 (K) similar to 900 mu Omega cm) for La2Os2AlB2, consistent with the electronic band structure calculations, which also predict a metallic character for LaOs2Al2B.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States); Energy Frontier Research Centers (EFRC) (United States). Center for Emergent Superconductivity (CES)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1352867
- Journal Information:
- Inorganic Chemistry, Vol. 54, Issue 16; ISSN 0020-1669
- Publisher:
- American Chemical Society (ACS)
- Country of Publication:
- United States
- Language:
- English
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