“…The element gold and gold-based clusters have several unique electronic, 1–3 optical, 4–8 chemical, 9,10 and catalytic 11–15 properties that have been, and still are, triggering an explosive growth in both experimental and theoretical studies so far. Gold has an electronic configuration of 5d 10 6s 1 but in contrast to other coinage metal atoms, the gold atom exhibits a typical sd hybridization, resulting from a strong relativistic effect of the heavy element 16 and emphasizing numerous specific and customized properties, particularly in its geometric and electronic structures.…”