Resonance Balance Shift in Stacks of Delocalized Singlet Biradicals

Two flavors: Intra- and intermolecular spin–spin interactions of unpaired electrons coexist and correlate in stacks of phenalenyl-based singlet biradicals. The electronic structure of the one-dimensional π–π chain is best represented by the superposition of formulas A and B in terms of the resonating valence-bond (RVB) model. Lower temperatures and higher pressures induce a resonance balance shift to the formula B. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.