Triple-shell symmetry in<i>α</i>-(Al,Si)-Mn

Abstract

We describe three-dimensional graphics modeling experiments executed on a calligraphic system. Utilizing precise data from neutron diffraction, a triple icosahedral shell has been identified in the \ensuremath{\alpha}-(Al,Si)-Mn phase. These triple shells are centered in the unit cell; the Pm3\ifmmode\bar\else\textasciimacron\fi{} structure is completed by double shells on the cube corners. The triple shell can also be viewed as a composite of twelve coordination icosahedra around the maganese sites on the second (MacKay) shell.