Similarly, for the H2 molecules both H atoms are coordinated to a single Pt centre. Several attempts to obtain a cluster geometry with two H atoms on neighbouring Pt centres were unsuccessful. Both Pt-H distances are similar in value, ranging from 1.607 to 1.821 Å and resulting in the H-H distance from 1.53 to 1.76 Å (the H-H distance in an isolated H2 molecule is 0.74 Å). The H2 ligand binding geometry indicates that its s bonding orbital is involved in the coordination with the Pt centre, in agreement with previous studies on H2 interaction with Pt surfaces . Again, the example of such an interaction is illustrated in Figure , taking [Pt3(CO)6-H2]4 2-as an example. Notably, for smaller clusters, significant structural deformations or even decomposition are observed during the H2 bonding (the upper Pt3 unit is moving further apart from the rest of the cluster). The presence of more Pt3 units stabilizes the structures. However, such deformations could limit efectiveness of these clusters and stability as catalysts in the hydrogen generation processes.