Entropy for Energy Laboratory · Synthesizability Game · High-entropy nuclear waste forms Johns Hopkins University

Synthesizability Game

A high-entropy ceramic for nuclear waste can contain several elements on each of two cation sites. Some compositions are synthesizable; others are not. Your goal is to find one that is.

  1. Choose the A or B site, then select elements from the periodic table. You can also drag elements directly onto a site.
  2. Press Check to calculate the synthesizability score, from 0 to 100.
  3. A score of 50 or higher is classified as synthesizable. If the score is below 50, change the elements and try again.
Adding to

A site

    Tap elements to add them here.

    B site

      Tap elements to add them here.

      Swipe sideways to see the whole table.

      • Alkali metals
      • Alkaline earth metals
      • Transition metals
      • Post-transition metals
      • Metalloids
      • Nonmetals
      • Noble gases
      • Lanthanides
      • Circle size: relative ionic radius
      Synthesizability ?? / 100

      Press Check to see the score.

      For educational purposes only.

      Cartoon unit cell of a ceramic with one element on each cation site
      The crystal before mixing.

      About the game

      We presented this game at the 2026 ARPA-E Energy Innovation Summit in San Diego.

      This game is for educational purposes only. Every element carries a weight for the A site and a weight for the B site. We set those weights by hand for the demonstration, from chemical judgment about which elements suit which site, and they combine into one score between 0 and 100. A research question about a specific composition needs first-principles calculations for that composition, followed by synthesis and testing.

      The research behind the game is published in Xu et al., Stabilizing iodine in pyrochlore: toward new nuclear waste forms, Precis. Chem. 4, 1211 (2026), and described on the Research page.