Related Experiment Video
Updated: Jun 24, 2026

Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
Characterizing the reactivity of metallic iron upon methylene blue discoloration in Fe0/MnO2/H2O systems
1Angewandte Geologie, Universität Göttingen, Goldschmidtstrasse 3, D-37077 Göttingen, Germany. cnoubac@gwdg.de
Abstract:
A simple method is proposed for testing the reactivity of elemental iron materials (Fe(0) materials) using methylene blue (MB) as reagent. The method is based on the oxidative reactivity of Fe(II) for reductive dissolution of MnO(2). Fe(II) is produced in-situ by the oxidation of a Fe(0) material. The in-situ formed Fe(II) reacted with MnO(2) delaying the bulk precipitation of iron corrosion products and thus MB co-precipitation (MB discoloration). For a given MnO(2), the extent of MB discoloration delay is a characteristic of individual Fe(0) materials under given experimental conditions. The MB discoloration method for testing the reactivity of Fe(0) materials is facile, cost-effective and does not involve any stringent reaction conditions.
Related Concept Videos
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
Microbes and Other Elemental Cycles
Redox Titration: Other Oxidizing and Reducing Agents
Ladder Diagrams: Redox Equilibria
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
Complexometric Titration: Overview
Properties of Transition Metals
