NC 2 contained two types of Au-Pt bonds with distances of 2.79 and 2.76 Å. This finding demonstrated that, among the 12 Pt-Au bonds, six bonds were elongated and the remaining six bonds were compressed to an equal extent (Figure and Table ). In contrast, 3 had two equivalent Pt-Au bonds (2.79 Å), each with the same length as the longest Pt-Au bond in 2 (Figure and Table ). Among the remaining 10 Pt-Au bonds in 3, two bonds (lengths of 2.75 Å) were more compressed than the other eight bonds (lengths between 2.78 and 2.76 Å). However, the difference between the shorter Pt-Au bonds (2.76 Å in 2 and 2.75 Å in 3) was small (0.01 Å). The icosahedral core of 4 had six types of Au-Pt bonds with lengths of 2.75, 2.76, ~2.77, ~2.77, 2.78, and 2.79 Å (Figure and Table ), similar to 3. Furthermore, the four longer and four shorter bonds of both 3 and 4 were similar in length, while the remaining four Pt-Au bonds of 4 were shorter than those of 3. Therefore, the icosahedral core of 4 was more compressed than that of 3. Overall, the order of icosahedral compression was estimated to be 2 > 4 > 3, which differed from the trend described by the icosahedral distortion values (3 > 4 > 2; Figure ).