Synthesis and the Ccystal and electronic structures of ternary rare-earth metal silicide suboxides:La10O3Si8 and Ce10O3Si8

INOR 860

Limin Wang, lwang2@uh.edu, Zhongjia Tang, ZTang@uh.edu, and Arnold M. Guloy, aguloy@uh.edu. Department of Chemistry and the Texas Center for Superconductivity, University of Houston, 4800 calhoun, Houston, TX 77204-5003
The synthesis, crystal structure and the chemical bonding of two new isostructural rare-earth silicon suboxides, La10O3Si8 and Ce10O3Si8, will be presented. The new suboxides were synthesized through high-temperature reactions of the pure metals and silicon under controlled oxygen atmosphere conditions. The complex rare-earth-metal silicide suboxides crystallize with a unique hexagonal crystal structure, as determined by single-crystal x-ray diffraction, that features 3-D framework of corner-shared La6O (or Ce6O) octahedra units and planar Si six-membered rings. Extended Hückel theoretical calculations on La10O3Si8 indicate that it features the concurrence of metal-metal bonds and homoatomic Si-Si bonds in the Si6 Zintl anion. The EHT results are in agreement with more sophisticated DFT calculations. Magnetic susceptibility measurements reveal that La10O3Si8 exhibits temperature independent paramagnetism, and Ce10O3Si8 exhibits ferromagnetism with a Curie temperature of 12 K.
 

Solid State Chemistry
1:30 PM-5:40 PM, Wednesday, August 22, 2007 BCEC -- 205B, Oral

Division of Inorganic Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007