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Green chemistry, similar to sustainable chemistry or circular chemistry, [1] is an area of chemistry and chemical engineering focused on the design of products and processes that minimize or eliminate the use and generation of hazardous substances. [2]
Chemical chameleon reaction. The chemical chameleon is a redox reaction, well known from classroom demonstrations, that exploits the dramatic color changes associated with the various oxidation states of manganese.
Catalytic oxidation with oxygen or air is a major application of green chemistry. There are however many oxidations that cannot be achieved so straightforwardly. The conversion of propylene to propylene oxide is typically effected using hydrogen peroxide, not oxygen or air.
Redox (/ ˈ r ɛ d ɒ k s / RED-oks, / ˈ r iː d ɒ k s / REE-doks, reduction–oxidation [2] or oxidation–reduction [3]: 150 ) is a type of chemical reaction in which the oxidation states of the reactants change. [4] Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a ...
blue-green-grey Chromium(III) hydroxide: Cr(OH) 6 3− yellowish Monochromate: CrO 2− 4 yellow Dichromate: Cr 2 O 2− 7 orange Manganese(II) Mn 2+ pale pink Manganese(III) Mn 3+ crimson Manganate(V) MnO 3− 4 deep blue Manganate(VI) MnO 2− 4 dark green Manganate(VII) (permanganate) MnO − 4 deep purple Iron(II) Fe 2+ greenish Cobalt(II ...
The Statue of Liberty, showing advanced patination; verdigris is responsible for the statue's iconic green colour.. Verdigris (/ ˈ v ɜːr d ɪ ɡ r iː (s)/) [1] is a common name for any of a variety of somewhat toxic [2] [3] [4] copper salts of acetic acid, which range in colour from green to a bluish-green depending on their chemical composition.
Iron oxide pigment. The brown color indicates that iron is at the oxidation state +3. Green and reddish brown stains on a limestone core sample, respectively corresponding to oxides/hydroxides of Fe 2+ and Fe 3+. Iron oxides feature as ferrous or ferric or both. They adopt octahedral or tetrahedral coordination geometry. Only a few oxides are ...
After the Second World War, there was a growing interest in green patinated copper sheets, which were intended primarily for architectural use. [18] [19] [20] Technologies for anodic oxidation of titanium, and later niobium and tantalum, have evolved since the mid-1960s. Technology for the anodic oxidation of stainless steel was developed too ...