Advanced Topic 695 of 1102 Inorganic Chemistry
Mond Process
Nickel is purified through volatile nickel tetracarbonyl.
In-depth explanation of Mond Process
The Mond process is a vapour phase refining method for nickel. Impure nickel is heated in carbon monoxide at about 50 degrees C, where it forms volatile nickel tetracarbonyl, Ni(CO)4, which separates from the solid impurities. In a second vessel at about 230 degrees C the gas decomposes and deposits pure nickel, releasing CO for recycling. The reaction Ni + 4CO giving Ni(CO)4 is reversible, so the two temperatures drive the forward and reverse steps. Nickel tetracarbonyl is extremely toxic, so the process needs careful containment.
Going deeper: Mond Process
Key ideas: Nickel purified by forming volatile Ni(CO)4 at 330 to 350 K: Ni + 4CO gives Ni(CO)4; then heating at about 450 to 470 K reverses it, depositing very pure Ni and releasing CO for reuse. Impurities such as Co and Fe do not form carbonyls under these conditions. Ni(CO)4 is tetrahedral, colorless, extremely toxic liquid, with Ni in oxidation state 0. A similar vapor-phase method is the van Arkel process for Ti and Zr using iodides.
Common mistakes and connections: Students think the reaction is irreversible; its reversibility with temperature (Le Chatelier, exothermic forward) is the basis. Ni(CO)4 obeys the 18-electron rule: 10 from Ni plus 8 from four CO. Links to metal carbonyls, equilibrium and refining of metals.
Visualization of Mond Process
Ni + 4CO to Ni(CO)4 is exothermic, so K is large at about 50 C and small at 230 C; the temperature swing drives forward and reverse steps. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Impure nickel reacts with carbon monoxide to give volatile Ni(CO)4, which decomposes at higher temperature to deposit pure nickel.
Frequently asked questions about Mond Process
What is Mond Process?
Nickel is purified through volatile nickel tetracarbonyl.
Is Mond Process a beginner, intermediate or advanced topic?
Mond Process is a advanced topic in Inorganic Chemistry. It builds on beginner and intermediate topics, so review those first if needed.
What should I learn before Mond Process?
Study these earlier topics in Inorganic Chemistry first: Thermite Reaction, Refining of Metals, Zone Refining.
What comes after Mond Process?
The next topics in Inorganic Chemistry are Organometallic Compounds and Metal Carbonyls.
Can I practise Mond Process with quizzes?
Yes. The interactive lesson includes a self-check question on Mond Process, and the Inorganic Chemistry quiz draws on every topic in this area.
Where Mond Process fits in Inorganic Chemistry
Mond Process is topic 80 of 113 in Inorganic Chemistry.