Kristallstruktur, thermische Zersetzung und Schwingungsspektrum von Ethylendiammonium-pentafluoromanganat(III), enH2MnF5 / Crystal Structure, Thermal Decomposition and Vibrational Spectrum of Ethylenediammonium-pentafluoromanganate(III), enH2MnF5

Abstract

Single crystals of enH2MnF5 (en = ethylenediamine) have been prepared from aqueous HF solution and the crystal structure was determined by X-ray diffraction: space group Cccm, Z = 16, a = 1710.5(4), b = 1799.2(4), c = 847.8(2) pm, R/wR = 0.040/0.028 for 977 reflections. The structure consists of kinked [MnF5]2-- chains built by MnF6 octahedra sharing trans vertices (angles Mn-F-Mn 161.2 and 157.8°). The bridging Mn-Fax bonds are strongly elongated by the Jahn-Teller effect (mean Mn-Fax 215.4, Mn-F 183.8 pm). Each of the enH2 2+ cations is connected to four anionic chains by hydrogen bonds forming a 3 D network. Thermal decomposition occurs between 200 and 380 °C in two steps giving finally MnF2. The IR spectra of enH2MnF5 and its decomposition products are reported.