Also in the area of nanoparticles, surface stress can play a significant role in the stabilization of decahedral nanoparticle and icosahedral twins. In both cases an arrangement of internal twin boundaries leads to lower energy surface energy facets. Balancing this there are nominal angular gaps (disclinations) which are removed by an elastic deformation. While the main energy contributions are the external surface energy and the strain energy, the surface stress couples the two and can have an important role in the overall stability.