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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 ...
Curium readily reacts with oxygen forming mostly Cm 2 O 3 and CmO 2 oxides, [53] but the divalent oxide CmO is also known. [67] 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. [29] [68] Upon heating to 600–650 °C in vacuum (about 0.01 Pa), it transforms into the ...
The Ellingham diagram plots the Gibbs free energy change (ΔG) for each oxidation reaction as a function of temperature. For comparison of different reactions, all values of ΔG refer to the reaction of the same quantity of oxygen, chosen as one mole O (1 ⁄ 2 mol O 2) by some authors [2] and one mole O 2 by others. [3] The diagram shown ...
The standard Gibbs free energy of formation (G f °) of a compound is the change of Gibbs free energy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most stable form of the element at 1 bar of pressure and the specified temperature, usually 298.15 K or 25 °C).
The limiting oxygen concentration is shown in the lower right of the diagram. The limiting oxygen concentration (LOC), [1] also known as the minimum oxygen concentration (MOC), [2] is defined as the limiting concentration of oxygen below which combustion is not possible, independent of the concentration of fuel. It is expressed in units of ...
Rather than combustion, organisms rely on elaborate sequences of electron-transfer reactions, often coupled to proton transfer. The direct reaction of O 2 with fuel is precluded by the oxygen reduction reaction, which produces water and adenosine triphosphate. Cytochrome c oxidase affects the oxygen reduction reaction by binding O 2 in a heme ...