Our focus on HCN is motivated by its believed central importance to prebiotic chemistry . Biologically relevant building blocks, such as nucleobases and amino acids, readily form via HCN self-reactions and hydrolysis (see e.g., (5) and ( )). HCN is a weak acid and has, like water, the ability to both accept and donate hydrogen bonds. As a result, HCN can form strong directional hydrogen bonded networks, and it is known to readily polymerize under a variety of conditions, forming components of star tar, or tholins .