openmaterials.ai / codes / reaction-network
Builds a weighted graph of balanced reactions among phases from thermochemistry data and searches it for low-cost multi-step routes to a target phase.
Nodes are combinations of up to n phases, and edges are balanced reactions weighted by a softplus cost of the Gibbs energy per reactant atom. The C-Cl-Li-Mn-O-Y network had 5855 nodes and 121,176 edges (McDermott 2021).
Formation enthalpies from the Materials Project, Gibbs energies from the Bartel descriptor, elemental G from FactSage, gases and A2CO3 from NIST-JANAF (McDermott 2021).
C = ln(1 + exp((273 K / T) dG)) maps dG per reactant atom to a positive weight, so exergonic steps are cheap and endergonic steps stay possible (McDermott 2021).
Yen's k shortest paths on Dijkstra, crossover reactions among intermediates from the phase diagram, then mass-balanced combinations via a pseudoinverse (McDermott 2021).
The code removes phases above a hull cutoff, interdependent steps and hypothetical intermediates. n = 2 reacting phases keeps the combinatorics in check (McDermott 2021).
Later versions rank single reactions by primary competition among the precursors and secondary competition with the target (McDermott 2023).
Among 3,017 reactions forming Y2Mn2O7 at 650 C, 2 NaMnO2 + 2 YOCl + 1/2 O2 sits on the Pareto front. Its chemical potential distance is 0.055 eV/atom against 1.608 (Li) and 0.924 (K). Todd 2021
From 2,536,160 binary reactions among 2417 phases, 82985 BaTiO3 routes were ranked and 9 tested. Metathesis routes gave mainly BaTiO3 at 600 to 700 C. BaCO3 + TiO2 was incomplete at 1000 C. McDermott 2023
Target, precursors, temperature, energy above hull cutoff and any open element such as O2.
Phases from the Materials Project get Gibbs energies, reactions are balanced and weighted.
k shortest paths to each target, crossover reactions, balanced combinations of steps.
Several low-cost pathways are listed. Compare them with in situ diffraction.