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Phase competition and the subsequent phase selection are important characteristics of alloy systems exhibiting numerous states of distinct symmetry but comparable energy. The stoichiometric Heusler alloy exhibits a martensitic transformation with concomitant reduction in symmetry from an austenitic phase (cubic) to a martensitic phase (tetragonal). A structural search was carried out for this alloy and it showed the existence of a number of structures with monoclinic and orthorhombic symmetry with ground state energies comparable to and even less than that of the structure, usually reported as the ground state at low temperatures. We describe these structures and focus in particular on the structural transition path from the to tetragonal and orthorhombic structures for this material. Calculations were carried out to study the Bain () and Burgers () transformations. The barrierless Burgers path yielded a stable martensitic phase with …