Conventional simultaneous thermal analysis, capillary-coupled TG-MS, in situ and ex situ Raman and Mossbauer spectroscopy, as well as chemical analysis have been used for the investigation of the first decomposition step of the mixed valence chloroferrate (dmpipzH(2))(6)[Fe(II)Cl-4](2)[Fe(III)Cl-4](2)[Fe(III)Cl-6]. Under argon at ca. 200 degrees C, an almost complete reduction proceeds in a solid state reaction forming Fe(II). It is accompanied by the release of HCl and, to a minor degree, carbon containing species. A multi-phase product with at least two chloroferrate species, coke, and C,H,N-containing polymers is formed. Binuclear iron complexes, such as (dmpipzH)(2)[Fe(II)(2)Cl-6], and small amounts of (dmpipzH)[Fe(III)Cl-4] have been proposed to be the major and minor component of the product mixture, respectively.