Electronic and Mössbauer spectra of some iron(II) halide hydrates

Abstract

Reflectance spectra in the near infrared region are reported for the compounds FeBr₂,6H₂O, FeX₂,4H₂O (X = F, Cl, Br, or I) and FeX₂,nH₂O (X = Cl or Br,n= 2 or 1). All the spectra, except that of the fluoride, show two electronic bands. For the compounds FeX₂,4H₂O (X = Cl, Br, or I) the transition ⁵B_2g→⁵B_1g lies to higher energy than ⁵B_2g→⁵A_1g, whereas for the lower hydrates the reverse is found. The spectrum of FeBr₂,6H₂O indicates that it contains trans-[Fe(H₂O)₄Br₂] units and not Fe(H₂O)₆²⁺ ions.

Some Mössbauer parameters for the compounds FeBr₂,nH₂O (n= 4 or 2) and FeCl₂,nH₂O (n= 2 or 1) are reported.