It is evident from Table and S9 that the S-H…S HBs, in these (H 2 O) m (H 2 S) n clusters are of substantially weaker strengths (1.35 to 4.23 kcal mol - ). In general, these S-H…S HBs are the weakest among all the interactions in the (H 2 O) m (H 2 S) n clusters. Furthermore, these S-H…S HB energies, in (H 2 O) m (H 2 S) n clusters, are found to be a little larger as compared to those in the pure (H 2 S) n clusters (2.08 to 3.88 kcal mol -1 ). This is because many of these S-H…S HBs in (H 2 O) m (H 2 S) clusters are in the vicinity of stronger O-H…O and O-H…S interactions. For instance, consider the hydrogen bonds, HB3 and HB4 in (H 2 O) 2 (H 2 S) 3 -A cluster; the energy of HB3 (3.59 kcal mol -1 ) is a little smaller than HB4 (3.91 kcal mol -1 ). This is because HB4 is in the vicinity of a stronger O-H…O hydrogen bond (HB1:7.61 kcal mol -1 ). On the other hand, HB3 is in the vicinity of weaker S-H…S hydrogen bond (HB4:3.91 kcal mol -1 ); see Figure . This is consistent with our earlier observation that the HB strengths are enhanced when they are in the neighbourhood of stronger HBs. The weakest strength of S-H…S HBs is also evident from the HB energies in dimers. For instance, the S-H…S HB energies in dimers fall in a much narrow range (1.54 to 3.04 kcal mol -1 ). These S-H…S HB energies in dimers are indeed smaller than the respective ones in the dimers of the O-H…O (3.99 to 5.69 kcal mol -1 ) and O-H…S (1.84 to 4.18kcal mol -1 ) HBs. As discussed above, the weaker HBs have smaller cooperativity contributions. Indeed, as seen from Table and S9, the cooperativity contributions toward the S-H…S HBs is much smaller (-0.90 to 1.67 kcal mol -1 ) than the O-H…O (-0.62 to 5.96kcal mol -1 ) and O-H…S (-0.83 to 3.34 kcal mol -1 ) HBs.