I am planning to do an experiment using manganese nitrate, so I bought Manganese(II) nitrate hexahydrate (Mn(NO3)2.6H2O). But when I received the reagent, it was kinda watery already (most part was still crystallized but there was also liquid in the bottle). After inspecting the bottle, it says that I need to refrigerate at 5 degree Celsius. But after I refrigerated it, the reagent became so hard (like a block of ice) that cannot take anything out. So I am now wondering how to handle this compound. I am afraid if I use the liquid part it will have various concentration, and it is barely impossible to use the solid part because it's so hard. Thank you.