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The method is used for the fabrication of metal oxides, especially the oxides of silicon (Si) and titanium (Ti). The process involves conversion of monomers in solution into a colloidal solution that acts as the precursor for an integrated network (or gel) of either discrete particles or network polymers. Typical precursors are metal alkoxides.
Two promising methods for the description of the acid–base properties of metal oxides are Calorimetric measurements of adsorption enthalpies and Temperature Programmed desorption. [16] The measurement of the heat of adsorption of basic or acidic probe molecules can give a description of acidic and basic sites on metal oxide surfaces ...
The complete metal metathesis from an integral part of the framework has been achieved without altering the framework or pore structure of the MOF. Similarly to post-synthetic ligand exchange, post-synthetic metal exchange is performed by washing prefabricated MOF crystals with solvent and then soaking the crystal in a solution of the new metal ...
Iron(III) oxide is a product of the oxidation of iron. It can be prepared in the laboratory by electrolyzing a solution of sodium bicarbonate, an inert electrolyte, with an iron anode: 4 Fe + 3 O 2 + 2 H 2 O → 4 FeO(OH) The resulting hydrated iron(III) oxide, written here as FeO(OH), dehydrates around 200 °C. [18] [19] 2 FeO(OH) → Fe 2 O 3 ...
Magnified crystals of iron(II,III) oxide (Fe 3 O 4), the end-product of the Schikorr reaction along with hydrogen gas. The Schikorr reaction formally describes the conversion of the iron(II) hydroxide (Fe(OH) 2) into iron(II,III) oxide (Fe 3 O 4). This transformation reaction was first studied by Gerhard Schikorr. The global reaction follows:
It forms by the reaction of metallic cobalt, its oxide, hydroxide, or carbonate with aqueous sulfuric acid: [1] Co + H 2 SO 4 + 7 H 2 O → CoSO 4 (H 2 O) 7 + H 2 CoO + H 2 SO 4 + 6 H 2 O → CoSO 4 (H 2 O) 7. The heptahydrate is only stable at humidity >70% at room temperature, otherwise it converts to the hexahydrate. [2]
Metal oxides which react with both acids as well as bases to produce salts and water are known as amphoteric oxides. Many metals (such as zinc, tin, lead, aluminium, and beryllium) form amphoteric oxides or hydroxides. Aluminium oxide (Al 2 O 3) is an example of an amphoteric oxide. Amphoterism depends on the oxidation states of the oxide.
Carbonic acid is an illustrative example of the Lewis acidity of an acidic oxide. CO 2 + 2OH − ⇌ HCO 3 − + OH − ⇌ CO 3 2− + H 2 O. This property is a key reason for keeping alkali chemicals well sealed from the atmosphere, as long-term exposure to carbon dioxide in the air can degrade the material.