Structurally Stable Saturated Heteropolyhedrane BCC Crystals Si24B8N8C6

<jats:p>We designed a new Si–B–C–N framework based on the Weaire–Phelan topology, identified a lower-energy chiral polymorph through DFT, and showed that its residual dynamical instability is confined to a single collective mode strongly coupled to B/N ordering and cage chirality.</jats:p>