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The tight-binding description of covalent bonding is used to propose a four-level, bond-order potential for elemental silicon. The potential addresses both the σ and π bonding and the valence of this sp -valent element. The interatomic potential is parametrized using ab initio and experimental data for the diamond cubic, simple cubic, face-centered-cubic, and body-centered-cubic phases of silicon. The bond-order potential for silicon is assessed by comparing the predicted values with other estimates of the cohesive energy, atomic volume, and bulk modulus for the β -Sn, bc8, st12, and 46 clathrate structures. The potential predicts a melting temperature of 1650 ± 50 K in good agreement with the experimental value of 1687 K. The energetics of various high-symmetry point defect structures and the structure and energetics of small silicon clusters are investigated. The potential also provides a robust description of surface reconstructions; it notably predicts with high fidelity the surface formation energy of the (111) 7x7 dimer adatom stacking fault configuration.