Using low-energy electron diffraction, a study was made of the reconstruction of Si(331). A (12 x 1) reconstruction was found which was characteristic of the clean surface. Evidence was presented that a previously observed (13 x 1) reconstruction was not the equilibrium structure. The (12 x 1) reconstruction disordered via a strongly first-order phase transition at about 810C. Heating carbon-contaminated surfaces to about 950C caused faceting to give (111) and {17 15 1} orientations. Low-Energy Electron Diffraction Study of the Reconstruction and Orientational Stability of Si(331). J.Wei, E.D.Williams, R.L.Park: Surface Science Letters, 1991, 250[1-3], L368-72