The first stages of the growth of iron disilicide on Si(111) were studied with scanning tunnelling microscopy. Nucleation and growth of 2-dimensional epitaxial islands of disilicide were obtained by means of a solid phase epitaxy method. Atomically resolved images show that the islands present a hexagonal closed-packed symmetry and correspond to the first stage of a new metastable cubic phase of FeSi2 which grows matching its (111) plane to the Si(111) surface. The surface of the islands showed a 2 x 2 reconstruction explained on the basis of the reduction in number of Si dangling bonds. The results permitted it to be seen in real space that metastable phases could be stabilized by hetero-epitaxial growth on suitable substrates. Real-Space Imaging of the First Stages of FeSi2 Epitaxially Grown on Si(111): Nucleation and Atomic Structure. A.L.Vazquez de Parga, J.de la Figuera, C.Ocal, R.Miranda: Europhysics Letters, 1992, 18[7], 595-600