A unique chemisorption structure was determined for the (√3 x √3)R30° H-Be(0001) phase formed at a saturation coverage of 1ML and up to ~270K. The analysis of low-energy electron diffraction data showed that 1/3 of the Be top layer atoms were removed to form a honeycomb structure of Be vacancies. Each vacancy was decorated by three H adatoms bonded in tilted bridge sites with a H-Be bond length and angle of 1.53Å and 42°, respectively.

Structure of the H-Induced Vacancy Reconstruction of the (0001) Surface of Beryllium. K.Pohl, E.W.Plummer: Physical Review B, 1999, 59, R5324-7