Open Question
Complete the exercises below. Which species are more likely to act as ligands? a. Positively charged ions or negatively charged ions? b. Neutral molecules that are polar or those that are nonpolar?
Ch.23 - Transition Metals and Coordination Chemistry
Chapter 23, Problem 25
Complete the exercises below. Indicate the coordination number and the oxidation number of the metal for each of the following complexes: a. Na₂ [CdCl₄] b. K₂ [MoOCl₄] c. [Co(NH₃)₄ Cl₂] Cl
Verified step by step guidance1
Step 1: Understand the structure of coordination complexes. A coordination complex consists of a central metal atom or ion bonded to surrounding molecules or ions, known as ligands. The coordination number is the number of ligand donor atoms bonded to the central metal, while the oxidation number is the charge of the metal after accounting for the charges of the ligands and any overall charge on the complex.
Step 2: Analyze complex (a) Na₂ [CdCl₄]. The complex ion is [CdCl₄]²⁻. The coordination number is determined by counting the number of Cl⁻ ligands attached to Cd, which is 4. To find the oxidation number of Cd, note that each Cl⁻ has a charge of -1, and the overall charge of the complex ion is -2. Set up the equation: x + 4(-1) = -2, where x is the oxidation number of Cd.
Step 3: Analyze complex (b) K₂ [MoOCl₄]. The complex ion is [MoOCl₄]²⁻. The coordination number is determined by counting the number of ligand donor atoms: 1 from O and 4 from Cl, totaling 5. To find the oxidation number of Mo, note that O typically has a charge of -2 and each Cl⁻ has a charge of -1. Set up the equation: x + (-2) + 4(-1) = -2, where x is the oxidation number of Mo.
Step 4: Analyze complex (c) [Co(NH₃)₄ Cl₂] Cl. The complex ion is [Co(NH₃)₄ Cl₂]⁺. The coordination number is determined by counting the number of ligand donor atoms: 4 from NH₃ and 2 from Cl, totaling 6. To find the oxidation number of Co, note that NH₃ is neutral and each Cl⁻ has a charge of -1. Set up the equation: x + 4(0) + 2(-1) = +1, where x is the oxidation number of Co.
Step 5: Solve the equations from Steps 2, 3, and 4 to find the oxidation numbers of Cd, Mo, and Co, respectively.
Related Practice
Open Question
Complete the exercises below. A complex is written as NiBr₂ • 6NH₃. a. What is the oxidation state of the Ni atom in this complex? b. What is the likely coordination number for the complex? c. If the complex is treated with excess AgNO₃ (aq), how many moles of AgBr will precipitate per mole of complex?
Open Question
Complete the exercises below. Crystals of hydrated chromium(III) chloride are green, have an empirical formula of CrCl₃ • 6H₂O, and are highly soluble. a. Write the complex ion that exists in this compound. b. If the complex is treated with excess AgNO₃ (aq), how many moles of AgCl will precipitate per mole of CrCl₃ • 6H₂O dissolved in solution? c. Crystals of anhydrous chromium(III) chloride are violet and insoluble in aqueous solution. The coordination geometry of chromium in these crystals is octahedral, as is almost always the case for Cr³⁺. How can this be the case if the ratio of Cr to Cl is not 1:6?
Open Question
Complete the exercises below. Indicate the coordination number and the oxidation number of the metal for each of the following complexes: e. NH₄[Cr(NH₃)₂(NCS)₄]
Open Question
Complete the exercises below. For each of the following molecules or polyatomic ions, draw the Lewis structure and indicate if it can act as a monodentate ligand, a bidentate ligand, or is unlikely to act as a ligand at all: a. ethylamine, CH₃CH₂NH₂, b. trimethylphosphine, P(CH₃)₃.
Open Question
Complete the exercises below. Polydentate ligands can vary in the number of coordination positions they occupy. In each of the following, identify the polydentate ligand present and indicate the probable number of coordination positions it occupies: a. [Co(NH₃)₄ (o-phen)] Cl₃.