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Ch.21 - Transition Elements and Coordination Chemistry
McMurry - Chemistry 8th Edition
McMurry8th EditionChemistryISBN: 9781292336145Not the one you use?Change textbook
All textbooksMcMurry 8th EditionCh.21 - Transition Elements and Coordination ChemistryProblem 21.78b
Chapter 21, Problem 21.78b

What is the systematic name for each of the following ions? 
(c) [Co(CO3)3]3-
(d) [Pt(en)2(SCN)2]2+

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1
Identify the central metal ion in each complex: (c) Cobalt (Co), (d) Platinum (Pt).
Determine the oxidation state of the central metal ion by considering the charges of the ligands and the overall charge of the complex: (c) Carbonate (CO_3) is a -2 charge ligand, (d) Ethylenediamine (en) is a neutral ligand and thiocyanate (SCN) is a -1 charge ligand.
For complex (c), calculate the oxidation state of cobalt: Let x be the oxidation state of Co. The equation is x + 3(-2) = -3. Solve for x.
For complex (d), calculate the oxidation state of platinum: Let y be the oxidation state of Pt. The equation is y + 2(0) + 2(-1) = +2. Solve for y.
Name the complexes using the IUPAC naming conventions: (c) Use the oxidation state of cobalt and the name of the ligands to form the name. (d) Use the oxidation state of platinum and the name of the ligands to form the name.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Coordination Compounds

Coordination compounds consist of a central metal atom bonded to surrounding molecules or ions called ligands. The arrangement and type of ligands influence the properties and naming of the compound. Understanding the structure of coordination complexes is essential for determining their systematic names.
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Ligands and Their Naming

Ligands are ions or molecules that donate electron pairs to the central metal atom in a coordination complex. They can be classified as monodentate, bidentate, or polydentate based on the number of donor atoms. The naming of ligands follows specific conventions, such as using prefixes to indicate the number of ligands present.
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Oxidation States and Charge

The oxidation state of a metal in a coordination compound is crucial for determining its systematic name. The overall charge of the complex ion must be considered, as it affects the naming convention. For example, the oxidation state of cobalt in [Co(CO3)3]3- must be calculated to accurately name the compound.
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Related Practice
Textbook Question

Cobalt(III) trifluoroacetylacetonate, Co(tfac)3, is a sixcoordinate, octahedral metal chelate in which three planar, bidentate tfac ligands are attached to a central Co atom:

(b) Diastereoisomers A and B have dipole moments of 6.5 D and 3.8 D, respectively. Which of your diastereoisomers is A and which is B?

Textbook Question

For each of the following complexes, draw a crystal field energy-level diagram, assign the electrons to orbitals, and predict the number of unpaired electrons.

(b) [MnCl4]2- (tetrahedral)

Textbook Question

For each of the following complexes, describe the bonding using valence bond theory. Include orbital diagrams for the free metal ion and the metal ion in the complex. Indicate which hybrid orbitals the metal ion uses for bonding, and specify the number of unpaired electrons. 

(b) [Ag(NH3)2]+

Textbook Question

Nickel(II) complexes with the formula NiX2L2, where X is Cl- or N-bonded NCS- and L is the monodentate triphenylphosphine ligand P(C6H5)3, can be square planar or tetrahedral.

(b) If NiCl2L2 is paramagnetic and Ni(NCS)2L2 is diamagnetic, which of the two complexes is tetrahedral and which is square planar?

Textbook Question

Spinach contains a lot of iron but is not a good source of dietary iron because nearly all the iron is tied up in the oxalate complex [Fe(C2O4)3]3-.

(c) Draw a crystal field energy-level diagram for [Fe(C2O4)3]3-, and predict the number of unpaired electrons. (C2O42- is a weak-field bidentate ligand.)

Textbook Question

The percent iron in iron ore can be determined by dissolving the ore in acid, then reducing the iron to Fe2+, and finally titrating the Fe2+ with aqueous KMnO4. The reaction products are Fe2+ and Mn2+.

(c) Draw a crystal field energy-level diagram for the reactants and products, MnO4-, 3Fe1H2O2642+, 3Fe1H2O2643+, and 3Mn1H2O2642+, and predict the number of unpaired electrons for each.