A new cubic half-Heusler structure LiBeN can be derived from the zinc-blende BN, and has a similar band structure to BN. The structural, elastic properties and band structures of LiBeN and zinc-blende BN were studied using the full potential augmented plane wave plus local orbitals method within density functional theory. The conduction band modifications of LiBeN, compared to its zinc-blende analog BN, were discussed. For both BN and LiBeN, the valence band top is at the I- point. For BN and alpha-LiBeN (Li+ near the anion), the conduction band minimum is at the X point. The beta-LiBeN (Li+ near the cation) has the conduction band minimum at the L point, due to the increase (decrease) of conduction band bottom energy at X (L) point, relative to I- point. The band gaps of LiBeN decrease compared to BN. The total energy calculations show the alpha phase to be more stable than the beta phase for LiBeN. (c) 2007 Elsevier B.V. All rights reserved.