Facile synthesis of anhydrous Li2B12H12 with high purity by solvent-free method

This work is aimed to synthesize anhydrous Li2B12H12 with high purity via solvent-free reaction between solid state reagents LiBH4 and B10H14. The reaction is conducted respectively in open system and sealed system for comparison. It is observed to experience three thermodynamic steps: (1) melting of B10H14 at 103 degrees C, (2) phase transition of LiBH4 at 118 degrees C and (3) Li2B12H12 formation at 135 degrees C. With appropriate heat treatment at 180 degrees C for 2 h, Li2B12H12 with purity high as 93% is obtained in open system of 2LiBH(4) + 1.4B(10)H(14) with excess B10H14. Sealed system reacting at approximate even optimized conditions is unavailable to produce such high purity of Li2B12H12. Chemical equilibrium confines the sufficient interaction between LiBH4 and B10H14 in sealed system but it does not do in open system. (C) 2017 Elsevier B.V. All rights reserved.