A discrete disclination model that describes the stored energy in icosahedral small particles (ISPs) is proposed. The particle energy is defined as a superposition of the energies of six interacting wedge disclinations, each of which connects the opposite vertices of the icosahedron. Isotropic elasticity analytical solution is given for a spheroid with the volume being equal to that of the icosahedron. Distributed disclination model, also known as Marks-Ioffe model, is used for calculation of the stored in ISP energy. The influence of the Poisson's ratio on the stored in ISP energy is studied within both considered disclination models.