Coexistence of metamagnetism and slow relaxation of magnetization in ammonium hexafluoridorhenate

Abstract

The (NH4)2[ReF6] (1) salt was studied by X-ray diffraction, Raman spectroscopy, theoretical calculations, and magnetic measurements.1crystallizes in the trigonal space groupP3̄m1 (Re-F = 1.958(5) Å). In the Raman spectrum of1, splitting of the observed peaks was observed and correlated to the valence frequencies of vibration of the [ReF6]2−anion. The study of the magnetic properties of1, through DC and AC magnetic susceptibility measurements, reveals the coexistence of metamagnetism and slow relaxation of magnetization at low temperature, which is unusual in the molecular systems based on the paramagnetic 5d metal ions reported so far.