The modeled FR CRNR allows tracking of the most highly connected, or "hub," species in the reaction graph, which may be pivotal species in real-world chemistry. The most highly connected in-degree molecules are water, formic acid, methanol, formaldehyde, acetaldehyde, CO 2 , glycolaldehyde, acrolein, glyoxal and methylglyoxal, in that order (Figure ). The highest connected out-degree node molecules are water, formaldehyde, acetaldehyde, acrolein, glycolaldehyde, CO 2 , propionaldehyde, acetone, methane and crotonaldehyde (Figure ). Notably, with the exception of crotonaldehyde which has E/Z isomers, none of these species contain stereocenters, though most of them offer an opportunity for stereospecific addition or condensation reactions. Out of the total ~350,000 reactions in the computed FR CRNR, there were only 78 reactions of the type A + B → 2 C or A → 2 B, with 70% being retro aldol reactions, and 30% being Knoevenagel C or H inverse reactions (an inverse reaction rule is simply the corresponding reverse reaction). 21 of these 78 reactions were assessed as thermodynamically spontaneous at pH 10 (with ΔG rxn < 0). Reactions which depend on the symmetry of the products and reactants are likely especially important for autocatalytic motifs and may represent "linchpin motifs" in autocatalytic reactions.