Hi all, 

I am working on hydrogen storing materials. I recently found a comes that shows increase in hardness values which is an indication of stability of complex upon successive h2 uptake. But I am facing an issue in that. Since my complex has two transition metals so upon h2 adsorption hydrogens alternate between two metal ions ie first h2 goes to first metal ion while 2h2 goes to 2nd metal ion and 3rd h2 goes two first metal ion and so.on. basically the upcoming h2 alteranate their h2 behaviour between two metal ions leading to ups and downs in the graph of hardness. But when all the h2 got adsorbed the hardness showed a sharp increase ie it moved towards stablity. So can anyone tell me what could b the reason for such alternate h2 adsorption trend. 

Thank u.