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Curium(III) oxide is a compound composed of curium and oxygen with the chemical formula Cm 2 O 3. It is a crystalline solid with a unit cell that contains two curium atoms and three oxygen atoms. The simplest synthesis equation involves the reaction of curium(III) metal with O 2−: 2 Cm 3+ + 3 O 2−---> Cm 2 O 3. [1]
Metallic curium is annealed in air or in an oxygen atmosphere: [1] Cm + O 2 → CmO 2. Curium(III) hydroxide and curium(III) oxalate are also usually used for this purpose: Cm(OH) 4 → CmO 2 + 2H 2 O Cm(C 2 O 4) 2 → CmO 2 + 2CO 2 + 2CO. Another way is the reaction of curium(III) oxide in an oxygen atmosphere at 650 °C: [2] 2Cm 2 O 3 + O 2 ...
Curium readily reacts with oxygen forming mostly Cm 2 O 3 and CmO 2 oxides, [1] but the divalent oxide CmO is also known. [2] Black CmO 2 can be obtained by burning curium oxalate (Cm 2 (C 2 O 4) 3), nitrate (Cm(NO 3) 3), or hydroxide in pure oxygen. [3] [4] Upon heating to 600–650 °C in vacuum (about 0.01 Pa), it transforms into the whitish ...
Figure 6:Reaction Coordinate Diagrams showing reactions with 0, 1 and 2 intermediates: The double-headed arrow shows the first, second and third step in each reaction coordinate diagram. In all three of these reactions the first step is the slow step because the activation energy from the reactants to the transition state is the highest.
In the second step, a stream of steam oxidises the previously obtained molecule back to its starting state, therefore closing the cycle. [1] Depending on the stoichiometry of the reactions, which is the relation of the reactants and products of the chemical reaction, these cycles can be classified in two categories. [4]
In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical reaction occurs. [1] A chemical mechanism is a theoretical conjecture that tries to describe in detail what takes place at each stage of an overall chemical reaction. The detailed steps of a reaction are not observable in most cases.
A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. [1] When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an energy change as new products are generated.
Cerium(IV) oxide, also known as ceric oxide, ceric dioxide, ceria, cerium oxide or cerium dioxide, is an oxide of the rare-earth metal cerium. It is a pale yellow-white powder with the chemical formula CeO 2. It is an important commercial product and an intermediate in the purification of the element from the ores.