The molecular and crystal structures of ethylenediamine triethylenediamine tetraperchlorate (SY) have been determined by XRD. The compound crystallizes in the orthorhombic system (space group Cmc21) with cell dimensions a=8.1030(16), b=24.725(5) and c=10.195(2) angstrom. Band structure and density of states (DOS) were calculated by a Dmol(3) method. The first principle tight-binding method within general gradient approximation (GGA) has been used to study the electronic band structure as well as density of states (DOS) and Fermi energy. (C) 2011 Elsevier B.V. All rights reserved.