The spectra measured before heating (never heated above room temperature) it can be seen For Pt 4 , 750 K heating led to a ˜2% increase in Pt intensity, well within the uncertainty, but for Pt 5 the intensity dropped by ˜20% -well outside the uncertainty. Pt 6 also showed a small heating-induced decrease, consistent with either a small degree of thermal sintering or thermal isomerization to more compact isomers. Finally, for Pt 7 , which had some multilayer isomers present before heating, there was no significant change. These data clearly show size-dependent sintering behaviour, and varying stabilities, which will be addressed below.