Über Manganoxyde. II. Zur Kenntnis des Mangan(VII)‐oxyds

Abstract

Die Darstellung von Mangan(VII)‐oxyd aus Kaliumpermanganat und konz. Schwefelsäure wird beschrieben, Mangan(VII)‐oxyd ist eine in der Aufsicht grüne, in der Durchsicht rote, ölige Flüssigkeit vom Smp. 5,9° und dem Zersetzungspunkt ∼55°. D 420 = 2,396; elektr. Leitfähigkeit x < 4 · 10−9 Ohm−1 · cm−1. Dielektrizitätskonstante ε20° = 3,28. Bei der langsamen Zersetzung von Mn2O7 bildet sich γ‐MnO2, beim explosionsartigen Zerfall entsteht α‐Mn2O3 (und geringe Mengen von Mn3O4). Zerfallsenthalpie nach Mn2O7 = α‐Mn2O3 + 2O2, ΔH = −55,3 ± 0,5 kcal. Bildungsenthalpie nach 2 Mn + 5/2 O2 = Mn2O7, ΔH = −177,4 ± 1,6 kcal. Mn2O7 ist eine außerordentlich gefährliche Substanz. Die Schlagempfindlichkeit entspricht der des Knallquecksilbers; seine Detonationsgeschwindigkeit beträgt 400 m/Sek.

A Novel Gas-phase Hydrogen Peroxide Sensor Basing on a Combined Physical/chemical Transduction Mechanism

“…For the preparation of γ-MnO 2 , Mn 2 O 7 and HMnO 4 have been prepared as described in [1,2]. After calcination (400 °C), a concentration of 63,5% oxygen and 36,5% manganese has been achieved and proven by EDX yielding a ratio of MnO 2 and Mn 2 O 3 of 1:1 [3].…”

Permanganyl Fluoride: A Brief History of the Molecule MnO3F and of Those Who Cared For It

“…As mentioned above, [4, 5] Mn 2 O 7 has a long history. However, its crystal and molecular structure have been determined as late as 1987 by a joint work of the groups of Arndt Simon and Bernt Krebs (Figure 10) working at the MPI in Stuttgart and at the University of Münster, [53] respectively, where the crystal structure of Tc 2 O 7 had first been elucidated earlier by the Krebs group [54] .…”

“…The first more extensive description of the properties of Mn 2 O 7 was provided by Oskar Glemser of the University of Göttingen in 1953 (Figure 2). [5] …”

Convenient Routes for the Preparation of Barium Permanganate and other Permanganate Salts

“…Mn 2 O 7 is not miscible with sulfuric acid and can be separated as a dark volatile liquid (d ϭ 2.396 g/cm 3 , mp. ϭ ϩ5.9°C[11]) or it can be extracted with…”