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) Na[Au(CN)2]
Ch.21 - Transition Elements and Coordination Chemistry
Chapter 21, Problem 73a
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
Verified step by step guidance1
Identify the components of the complex: Pt(en)2 consists of a platinum (Pt) metal center and two ethylenediamine (en) ligands.
Determine the oxidation state of the metal: Ethylenediamine (en) is a neutral ligand, so it does not affect the oxidation state of the metal. Therefore, the oxidation state of Pt is 0.
Determine the coordination number: Each ethylenediamine ligand is bidentate, meaning it forms two bonds with the metal center. With two en ligands, the coordination number of Pt is 4.
Determine the coordination geometry: With a coordination number of 4, the geometry is typically square planar for platinum complexes.
Draw the structure: Represent the Pt at the center with two en ligands forming a square planar geometry around it. Each en ligand forms two bonds with the Pt, creating a square shape.
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Oxidation State
The oxidation state of an element in a compound indicates the degree of oxidation of that element, reflecting the number of electrons lost or gained. In coordination complexes, the oxidation state of the metal can be determined by considering the charges of the ligands and the overall charge of the complex. For example, in Pt(en)2, the oxidation state of platinum can be calculated based on the neutral nature of the ethylenediamine (en) ligands.
Recommended video:
Guided course
02:42
Oxidation Numbers
Coordination Number
The coordination number refers to the number of ligand atoms that are directly bonded to the central metal atom in a coordination complex. It is crucial for understanding the structure and stability of the complex. In the case of Pt(en)2, each ethylenediamine ligand coordinates through two donor atoms, leading to a coordination number of 4 for platinum.
Recommended video:
Guided course
00:27Coordination Numbers
Coordination Geometry
Coordination geometry describes the spatial arrangement of the ligands around the central metal atom in a coordination complex. This geometry is influenced by the coordination number and the steric and electronic properties of the ligands. For Pt(en)2, with a coordination number of 4, the geometry is typically square planar, which is common for d8 metal complexes like platinum.
Recommended video:
Guided course
02:40Molecular Geometry of Coordination Complexes
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) [Cr(NH3)2(C2O4)2]NO2
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.