Pushing TC to 27.5 K in a heavy atom radical ferromagnet

In the solid state the iodo-substituted bisdiselenazolyl radical 1c orders as a ferromagnet with T-C = 10.5 K. With the application of pressure T-C rises rapidly, reaching a value of 27.5 K at 2.4 GPa. The accompanying structural and magnetic changes have been examined by high resolution powder X-ray diffraction and by DFT calculations of magnetic exchange interactions.