Four-coordinate metals can have either a tetrahedral or a square-planar geometry; both possibilities are shown here for $\left[\mathrm{Pt} \mathrm{Cl}_{2}\left(\mathrm{NH}_{3}\right)_{2}\right] .(\mathbf{a})$ What is the name of this molecule? (b) Would the tetrahedral molecule have a geometric isomer? (c) Would the tetrahedral molecule be diamagnetic or paramagnetic? (d) Would the square- planar molecule have a geometric isomer? (e) Would the square-planar molecule be diamagnetic or paramagnetic? (f) Would determining the number of geometric isomers help you distinguish between the tetrahedral and square-planar geometries? (g) Would measuring the molecule's response to a magnetic field help you distinguish between the two geometries? [Sections \(23.4-23.6]\)

Step by step solution

01

(a) Name of the molecule

The complex under consideration is \(\left[\mathrm{Pt}\mathrm{Cl}_{2}\left(\mathrm{NH}_{3}\right)_{2}\right]\). To name this complex, we follow the IUPAC rules, where we list the ligands alphabetically, followed by the central metal atom. In this case, our ligands are two chlorides (Cl) and two ammonia molecules (NH3). Therefore, the name of the molecule is "diamminedichloroplatinum(II)."

02

(b) Geometric isomerism in tetrahedral geometry

Geometric isomers are molecules with the same chemical formula but different spatial arrangements of their atoms. In tetrahedral geometry, all four ligand positions are equivalent, so no geometric isomers are possible for this molecule.

03

(c) Magnetic properties in tetrahedral geometry

In the tetrahedral geometry, the molecule would be diamagnetic, as platinum (II) has a d8 configuration: 1s² 2s² 2p6 3s² 3p6 3d10 4s² 4p6 4d8. All the d-electrons are thus paired, and there are no unpaired electrons. Diamagnetic substances have no unpaired electrons and are not attracted to a magnetic field.

04

(d) Geometric isomerism in square-planar geometry

In square-planar geometry, different spatial arrangements of the ligands are possible. For the molecule \(\left[\mathrm{Pt}\mathrm{Cl}_{2}\left(\mathrm{NH}_{3}\right)_{2}\right]\), there are two possible geometric isomers: cis and trans. In the cis isomer, both ammonia ligands are adjacent to each other, while in the trans isomer, the ammonia ligands are opposite to each other. So, the square-planar molecule has geometric isomers.

05

(e) Magnetic properties in square-planar geometry

In the square-planar geometry, the molecule would also be diamagnetic. The reason is the same as for the tetrahedral geometry - platinum (II) has a d8 configuration with all its d-electrons paired, hence there are no unpaired electrons.

06

(f) Distinguishing between tetrahedral and square-planar geometries using geometric isomers

As we have discussed earlier, the tetrahedral molecule doesn't have geometric isomers, while the square-planar molecule does have geometric isomers (cis and trans). Therefore, the presence of geometric isomers can be used to distinguish between tetrahedral and square-planar geometries of the complex.

07

(g) Distinguishing between tetrahedral and square-planar geometries using magnetic properties

As previously discussed, both the tetrahedral and the square-planar molecules are diamagnetic because no unpaired electrons are present in the platinum (II) d8 configuration. Therefore, measuring the magnetic properties of the molecule would not help in distinguishing between these two geometries, as both of them would be diamagnetic.

Unlock Step-by-Step Solutions & Ace Your Exams!

• Full Textbook Solutions

  Get detailed explanations and key concepts

• Unlimited Al creation

  Al flashcards, explanations, exams and more...

• Ads-free access

  To over 500 millions flashcards

• Money-back guarantee

  We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!