röntgenium

— Gold crystallises in the face-centred cubic (fcc) habit, its lattice constant being fractionally smaller than that of silver (Tables 2.1 and 2.2.); in compounds and complexes, Auᴵ is smaller than Agᴵ. This is in consequence of the relativistic contraction of the 6s level, and it is expected that it will be even greater with the 7s level; indeed the size of the next element of Group 11 (röntgenium) has been calculated to be no larger than that of copper.