  A new silicene-like family of reconstructed surfaces on Si111 are discussed
which appears to be a polymorph to the well know family of surface
reconstructions best epitomized by the 7x7 surface. Several experimental
features are discussed which lead to this new conclusion, as are several
recently established limitations of density functional theory that may
currently limit its ability to predict such 2-D surface structures. The atomic
locations of the surface state charge densities from several Scanning Tunneling
Spectroscopy studies provide the basis for this new structure which is
supported by several previous measurements. The new structure appears to favor
a faulted supercell honeycomb motif having a delocalized 2-D state that enables
greater sp2 character. This top layer has an unusual periodic pi-orbital
structure that also interdigitates with the terminal bulk 'dangling bonds' to
create a 2-D pi-bonded structure. This new polymorphic structure resolves many
long standing paradoxes of the 7x7 surface while its unusual bonding and
structure may help better understand some silicenes as well as the behavior of
other 2-D phases on 111 surfaces.
