Textbook Question
Draw the structure of the following complexes. What are the oxidation state, coordination number, and coordination geometry of the metal in each?
(a) Pt(en)2
Ch.21 - Transition Elements and Coordination Chemistry
Chapter 21, Problem 75
Identify the Lewis acid and the Lewis base in the reaction of oxalate ions (C2O42-) with Fe3+ to form [Fe(C2O4)3]3-. (a) Identify the ligands and donor atoms. (b) Give the coordination number and geometry of the metal in the complex.
Verified step by step guidance1
Step 1: Understand the concept of Lewis acids and bases. A Lewis acid is a species that can accept an electron pair, while a Lewis base is a species that can donate an electron pair.
Step 2: Identify the Lewis acid and base in the reaction. In the given reaction, Fe^{3+} is the Lewis acid because it can accept electron pairs, and C_2O_4^{2-} (oxalate ion) is the Lewis base because it can donate electron pairs.
Step 3: Identify the ligands and donor atoms. In the complex [Fe(C_2O_4)_3]^{3-}, the oxalate ion acts as a bidentate ligand, meaning it can form two bonds with the metal ion. The donor atoms in the oxalate ion are the two oxygen atoms that coordinate with the Fe^{3+}.
Step 4: Determine the coordination number of the metal. The coordination number is the number of ligand donor atoms bonded to the central metal ion. Since each oxalate ion forms two bonds and there are three oxalate ions, the coordination number of Fe^{3+} is 6.
Step 5: Identify the geometry of the metal complex. With a coordination number of 6, the geometry of the complex is typically octahedral. Therefore, the geometry of [Fe(C_2O_4)_3]^{3-} is octahedral.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Lewis Acids and Bases
Lewis acids are species that can accept an electron pair, while Lewis bases are those that can donate an electron pair. In the reaction between oxalate ions (C2O4^2-) and Fe3+, the oxalate acts as a Lewis base by donating electron pairs to the metal ion, Fe3+, which functions as a Lewis acid by accepting these pairs.
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Lewis Acids and Bases
Coordination Complexes
Coordination complexes consist of a central metal atom or ion bonded to surrounding molecules or ions called ligands. In this case, the oxalate ions serve as bidentate ligands, meaning they can attach to the metal at two sites, forming a stable complex with the metal ion.
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00:43Coordination Complexes Example
Coordination Number and Geometry
The coordination number refers to the number of ligand donor atoms that are bonded to the central metal ion. In the complex [Fe(C2O4)3]3-, the coordination number is 6, as each oxalate ligand donates two pairs of electrons, leading to an octahedral geometry around the Fe3+ ion.
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Related Practice
Textbook Question
Draw the structure of the following complexes. What are the oxidation state, coordination number, and coordination geometry of the metal in each?
(b) [Co(H2O)5Cl]SO4]
Textbook Question
(a) Identify the Lewis acid and the Lewis base in the reaction of ethylenediamine (H2NCH2CH2NH2) with Ni2+ to form [Ni(en)3]2+.
(b) Identify the ligands and donor atoms.
(c) Give the coordination number and geometry of the metal in the complex.
Textbook Question
What is the systematic name for each of the following coordination compounds?
(a) [Cu(NH3)4]SO4
(b) Cr(CO)6
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Textbook Question
What is the systematic name for each of the following coordination compounds?
(c) K3[Fe(C2O4)3]
(d) [Co(en)2(NH3)CN]Cl2
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