Exploring the Effects of Synthetic and Postsynthetic Grinding on the Properties of the Spin Crossover Material [Fe(atrz)3](BF4)2 (atrz = 4-Amino-4H-1,2,4-Triazole)

The effects of mechanochemical synthesis and postsynthetic grinding on the spin crossover material [Fe(atrz)(3)](BF4)(2) was examined in detail using a combination of X-ray diffraction, magnetometry, EXAFS and TEM. Mechanochemical synthesis yielded a different polymorph (beta-phase) to the solution synthesised sample (alpha-phase), with a lower temperature spin crossover. Milling duration did not significantly affect this temperature but did result in the production of smaller nanoparticles with a narrower size distribution. It is also possible to convert from alpha- to the beta-phase via postsynthetic grinding.