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Pourbaix diagram of iron. [1] The Y axis corresponds to voltage potential. In electrochemistry, and more generally in solution chemistry, a Pourbaix diagram, also known as a potential/pH diagram, E H –pH diagram or a pE/pH diagram, is a plot of possible thermodynamically stable phases (i.e., at chemical equilibrium) of an aqueous electrochemical system.
Platinum and gold can be ... 8: 5: Ru 3+ + 3 e − → Ru: 0.6: 2.2 ... The simplified entries in the reaction column can be read in detail from the Pourbaix diagrams ...
The and pH of a solution are related by the Nernst equation as commonly represented by a Pourbaix diagram (– pH plot). For a half cell equation, conventionally written as a reduction reaction (i.e., electrons accepted by an oxidant on the left side):
Pourbaix Diagrams are thermodynamic charts constructed using the Nernst equation and visualize the relationship between possible phases of a system, bounded by lines representing the reactions that transport between them. They can be read much like a phase diagram. In 1963, Pourbaix produced "Atlas of Electrochemical Equilibria", which contains ...
The brain maintains a pH of around 7.2 to 7.4, and from the Pourbaix diagram of platinum [3] it can be seen that at around 0.8 volts Pt at the surface will oxidize to PtO 2, and at around 1.6 volts, PtO 2 will oxidize to PtO 3. These voltages do not seem to be outside of reasonable range for neural stimulation.
Boundaries between micro grains, if the oxide layer is crystalline, form an important pathway for oxygen to reach the unoxidized metal below. For this reason, vitreous oxide coatings – which lack grain boundaries – can retard oxidation. [8] The conditions necessary, but not sufficient, for passivation are recorded in Pourbaix diagrams.
The Pourbaix diagram for chromium in pure water, perchloric acid, or sodium hydroxide [27] [28] Chromium is a member of group 6, of the transition metals. The +3 and +6 states occur most commonly within chromium compounds, followed by +2; charges of +1, +4 and +5 for chromium are rare, but do nevertheless occasionally exist. [29] [30]
A Latimer diagram of a chemical element is a summary of the standard electrode potential data of that element. This type of diagram is named after Wendell Mitchell Latimer (1893–1955), an American chemist.