  A grand unified model (GUM) has been proposed recently to understand
structure anatomy and evolution of liganded gold clusters. In this work,
besidesthe two types of elementary blocks (triangular Au3(2e) and tetrahedral
Au4(2e)), we introduce a secondary block, namely, the icosahedral Au13 with 8e
valence electrons, noted as Au13(8e). Using this secondary block, structural
anatomy and evolution of a special group of liganded gold nanoclusters
containing icosahedral Au13 motifs can be conveniently analyzed. In addition, a
new ligand-protected cluster Au49(PR3)10(SR)15Cl2 is predicted to exhibit high
chemical and thermal stability, suggesting likelihood of its synthesis in the
laboratory.
