- Definition of Co(OH)3:
Co(OH)3, also known as cobalt(III) hydroxide, is a brown-black solid that is insoluble in water. In English, it is called “cobalt(III) hydroxide”.
The atomic mass of Co(OH)3 includes 1 cobalt atom (Co), 3 oxygen atoms (O) and 3 hydrogen atoms (H). The atomic mass of Co(OH)3 is about 92.94 g/mol.
The molecular structure of Co(OH)3 consists of 1 cobalt molecule forming an ionic bond with 3 hydroxyl molecules (OH-). The ionic structure of Co(OH)3 is [Co(OH)3]^-.
- Properties of Co(OH)3:
2.1 Physical properties: Co(OH)3 is a brown-black solid, odorless and insoluble in water. The pH of Co(OH)3 solution is about 9-10, indicating its weak base nature.
2.2 Chemical properties: Co(OH)3 is very insoluble in water but soluble in acid. It also reacts with alkalis to form complex compounds.
- Common chemical equations involving Co(OH)3:
As Co(OH)3 does not easily react with metals, acids or nonmetals, there are not many examples of related chemical equations.
- Synthesis of Co(OH)3:
4.1 Lab synthesis: Co(OH)3 can be synthesized through a reaction between cobalt(II) nitrate and sodium hydroxide.
Co(NO3)2 + 2NaOH -> Co(OH)2 + 2NaNO3
Afterward, Co(OH)2 is oxidized by air to form Co(OH)3.
4.2 Industrial synthesis: The current technology for producing Co(OH)3 mainly involves the reaction between cobalt sulfate and sodium hydroxide in an alkaline environment.