Fig. 6: 3D atomic structure of the ICNP-8 without an I_h center atom.

a, b The two distinct faces of the icosahedra-like particle with eight axes, including three fivefold axes, three pseudo-fivefold axes, and two sets of twin axes. In Face B, each of four distorted tetrahedra is marked with a small red triangle. Three large fcc domains are marked with black lines; the black dash lines illustrate the two tetrahedra-like grains without clear hcp grain boundaries. Scale bar: 1 nm. The atomic structures of two sets of twin axes, C5 + C5′ (c) and C5′ + C5′ (d). The bonds in five-atom rings and six-atom rings are marked red and green, respectively. e, f The front view and top view of the repeated coordination unit of (c) and (d), respectively. The dashed line box in (f) highlight the coordinated atoms of the center pseudo-D_h atom. The balls in the atomic model with yellow, blue, light purple, dark purple, and white color represent the atoms with fcc, hcp, D_h, I_h, and amorphous structures, respectively. The balls in the atomic model with red and green color represent the ending atoms in fivefold and sixfold axis, respectively.