First-order phase transition in the Li2B12H12 system

• DOI: 10.1039/c3cp53090f
• Publication Date: 2013-08-24T08:31:36Z
• Authors: Mark Paskevicius; Mark P. Pitt; David H. Brown; Drew A. Sheppard; Somwan Chumphongphan; Craig E. Buckley
• Keywords: Anhydrous; Lattice (music)

The thermal decomposition of anhydrous Pa3[combining macron] Li2B12H12 was studied in situ by high resolution synchrotron X-ray diffraction. A first-order phase transition can be observed at 355 °C where the unit cell volume expands ca. 8.7%. expanded β-Li2B12H12 polymorph simultaneously decomposes to a hydrogen poor γ-Li2B12H12-x phase. Expansion across discontinuity is consistent with reorientational motion B12H12(2-) anions, and presence frustrated Li(+) lattice indicating Li ion conduction.