Question

Part A Name the complex ion [Fe(CN)6]^3- . The oxidation number of iron is +3. Part B Name the complex ion [Cu(NH3)2(H2O)4]^2+ . The oxidation number of copper is +2. Part C Name the complex CrCl2(en)2 . The oxidation number of chromium is +2. Part D Name the salt [Ni(H2O)3(Co)]SO4 . The oxidation number of nickel is +2. Part E Name the salt K4[Pt(CO3)2F2] given that the carbonate ion acts as a monodentate ligand in the complex. The oxidation number of platinum is +2.

Answer 1

The complexes are sodium hexachloroplatinate(IV), potassium trisoxalatoferrate(III), and pentaamminechlorocobalt(III) chloride.

Step-by-step explanation:

(a) There are two Na+ ions, so the coordination sphere has a negative two charge: [PtCl6]². There are six anionic chloride ligands, so -2 = -6 + x, and the oxidation state of the platinum is 4+. The name of the complex is sodium hexachloroplatinate(IV), and the coordination number is six.

(b) The coordination sphere has a charge of 3- (based on the potassium) and the oxalate ligands each have a charge of 2-, so the metal oxidation state is given by -3 = -6+ x, and this is an iron(III) complex. The name is potassium trisoxalatoferrate(III) (note that tris is used instead of tri because the ligand name starts with a vowel). Because oxalate is a bidentate ligand, this complex has a coordination number of six.

(c) In this example, the coordination sphere has a cationic charge of 2+. The NH3 ligand is neutral, but the chloro ligand has a charge of 1-. The oxidation state is found by +2 = -1 + x and is 3+, so the complex is pentaamminechlorocobalt(III) chloride and the coordination number is six.