The invention relates to a new phase of silicon, Si.sub.24, and a method of making the same. Si.sub.24 has a quasi-direct band gap, with a direct gap value of 1.34 eV and an indirect gap value of 1.3 eV. The invention also relates to a compound of the formula Na.sub.4Si.sub.24 and a method of making the same. N.sub.a4Si.sub.24 may be used as a precursor to make Si.sub.24.
STATEMENT OF INTEREST
 This invention was made with Government support under Grant Number W911NF-11-1-0300 awarded by the U.S. Army Contracting Command and Grant Number DE-5G0001057 awarded by the U.S. Department of Energy. The U.S. Government has certain rights in the invention.