Nonaromatic Planar Si12 Ring System of ApproximateD6h Symmetry in Ca7Mg7.5±δSi14

Ca7Mg7.5±δSi14is a stoichiometric Zintl compound containing a planar ring system of six Si rings and six terminal silicon atoms (see diagram). These cluster anions form a one-dimensional infinite pile of ecliptically stacked Si12 units.