Parallels can be drawn between the behaviours of metal nitrides in liquid NH3 and of metal oxides in aqueous media. Many similar analogies can be drawn. Complex formation between Mg2+and NH3 leads to[Mg(NH3)6]2+, isolated as [Mg(NH3)6]Cl2. Similarly, in liquid NH ,CaCl2
forms [Ca(NH3)6]Cl2 and this is the reason that anhydrous CaCl2 (which readily absorbs water,
see Section 12.5) cannot be used to dry NH3. Ammine complexes such as [Ni(NH3)6]2+can be prepared in aqueous solution by the displacement of aqua ligands by NH3. Not all hexaammine complexes are, however, directly accessible by this method. Two examples are [V(NH3)6]2+and [Cu(NH3)6]2+. The ion [V(OH2)6]2+ is readily oxidized in aqueous solution, making the preparation of V(II) complexes in aqueous conditions difficult. In liquid NH3 , dissolution of VI2 gives [V(NH3)6]I2 containing the octahedral [V(NH3)6]2+ ion. The [Cu(NH3)6]2+ ion is not accessible in aqueous solution (see Fig. 20.37) but can be formed in liquid NH3.
Parallels can be drawn between the behaviours of metal nitrides in liquid NH3 and of metal oxides in aqueous media. Many similar analogies can be drawn. Complex formation between Mg2+and NH3 leads to[Mg(NH3)6]2+, isolated as [Mg(NH3)6]Cl2. Similarly, in liquid NH ,CaCl2forms [Ca(NH3)6]Cl2 and this is the reason that anhydrous CaCl2 (which readily absorbs water,see Section 12.5) cannot be used to dry NH3. Ammine complexes such as [Ni(NH3)6]2+can be prepared in aqueous solution by the displacement of aqua ligands by NH3. Not all hexaammine complexes are, however, directly accessible by this method. Two examples are [V(NH3)6]2+and [Cu(NH3)6]2+. The ion [V(OH2)6]2+ is readily oxidized in aqueous solution, making the preparation of V(II) complexes in aqueous conditions difficult. In liquid NH3 , dissolution of VI2 gives [V(NH3)6]I2 containing the octahedral [V(NH3)6]2+ ion. The [Cu(NH3)6]2+ ion is not accessible in aqueous solution (see Fig. 20.37) but can be formed in liquid NH3.
การแปล กรุณารอสักครู่..
