Principles of Descriptive Inorganic Chemistry

Gary Wulfsberg

Chapter 7 Coordination Compounds and the Lewis Acid-Base Concept - all with Video Answers

Educators

Chapter Questions

Problem 1

Draw the Lewis dot structures of the following molecules or ions, and identify the potential donor atoms in each:
a. $\mathrm{NH}_3$;
b. $\mathrm{NH}_2-\mathrm{CH}_2-\mathrm{COOH}$ (an amino acid);
c. $\mathrm{SO}_4{ }^{2-}$;
d. $\mathrm{SO}_3^{2-}$

Lottie Adams

Numerade Educator

01:46

Problem 2

a. Draw Lewis dot structures of the following complex ions:
$\left[\mathrm{Au}\left(\mathrm{CH}_3\right)_2\left(\mathrm{NH}_3\right)_2\right]^{+}$:
$\left[\mathrm{Na}\left(\mathrm{CH}_3-\mathrm{O}-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{O}-\mathrm{CH}_3\right)_3\right]^{+}$:
$\left[\mathrm{SnI}_6\right]^{2-} ;\left[\mathrm{HgCl}_2\right] ;\left[\mathrm{Hg}\left(\mathrm{CH}_3\right)_2\right]$. Treat all the bonds to the metal as coordinate covalent bonds. b. Write the formulas (including charges, if any) of the ligands found in each complex ion. c. Underline the donor atoms in those ligands. $\mathbf{d}$. Write the formulas of the Lewis acids (including charges, if any) found in these complex ions. e. Give the coordination number of the metal atoms in each of these complex ions.

Lottie Adams

Numerade Educator

12:34

Problem 3

Below are drawn Lewis structures of two coordination compounds. Treat all bonds to the central metal atom in each as coordinate covalent bonds. For each complex: a. Write the formulas (including charges) of each ligand. b. Tell which ligand (if any) is a chelating ligand. c. Write the formula (including charge) of the central metal ion. d. Write the formula of the counterion for the complex ion (if any).
FIGURE CANT COPY

Maryam Riaz

Numerade Educator

02:26

Problem 4

For the complexes $\left(\mathrm{NH}_4\right)_2\left[\mathrm{Pd}(\mathrm{SCN})_4\right]$ and $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5\left(\mathrm{SeO}_4\right)\right] \mathrm{ClO}_4$ : a. Write the electron-dot structure for each kind of ligand, showing unshared electron pairs and underlining its donor atom(s). b. Give the charge on each free ligand. c. Give the coordination number of the central (metal) atom. d. Give the oxidation number of the central (metal) atom.

Aadit Sharma

Numerade Educator

04:07

Problem 5

Pretend you are Alfred Werner. You have, by painstaking work, isolated the following set of compounds:
$$
\begin{array}{ll}
\mathrm{PdCl}_2: 4\left(\mathrm{CH}_3\right)_3 \mathrm{P} & \text { (contains } 3 \text { ions; } 2 \mathrm{Cl}^{-} \text {ions pptd. by } \mathrm{Ag}^{+} \text {) } \\
\mathrm{PdCl}_2: 3\left(\mathrm{CH}_3\right)_3 \mathrm{P} & \text { (contains } 2 \text { ions; } 1 \mathrm{Cl}^{-} \text {ion pptd. by Ag} \text { ) } \\
\mathrm{PdCl}_2: 2\left(\mathrm{CH}_3\right)_3 \mathrm{P} & \text { (contains } 0 \text { ions; } 0 \mathrm{Cl}^{-} \text {ion pptd. by } \mathrm{Ag}^{+} \text {) }
\end{array}
$$
$$
\begin{array}{ll}
\mathrm{PdCl}_2:\left(\mathrm{CH}_3\right)_3 \mathrm{P}: \mathrm{KCl} & \text { (contains } 2 \text { ions; } 0 \mathrm{Cl}^{-} \text {ion pptd. by } \mathrm{Ag}^{+} \text {) } \\
\mathrm{PdCl}_2: 2 \mathrm{KCl} & \text { (contains } 3 \text { ions; } 0 \mathrm{Cl}^{-} \text {ion pptd. by } \mathrm{Ag}^{+} \text {) }
\end{array}
$$
a. Write the formulas of each of these compounds in the modern form, with complex ions enclosed in brackets. b. What is the coordination number of palladium in this series of compounds? (It is constant.)

Crystal Wang

Numerade Educator

02:21

Problem 6

List the functions of metal ions in enzymes.

Alexander Cheng

Numerade Educator

02:25

Problem 7

Complexes containing coordinated $\mathrm{NH}_3$ and $\mathrm{H}_2 \mathrm{O}$ arc common, as are complexes containing coordinated $\mathrm{R}_3 \mathrm{~N}, \mathrm{R}_2 \mathrm{O}, \mathrm{R}_3 \mathrm{P}, \mathrm{R}_2 \mathrm{~S}$, etc. But complexes containing coordinated $\mathrm{PH}_3$ and $\mathrm{H}_2 \mathrm{~S}$ (or $\mathrm{RPH}_2$ and $\mathrm{RSH}$ ) are very seldom seen. Suggest a possible reason why, based on the concepts given in Sections 5.5 and 7.2.

April Berlyoung

Numerade Educator

03:10

Problem 8

Draw the Lewis dot structures of each of the following molecules or ions. Predict the bond angles (including distortions) about the central atom in each species. Give the name of the resulting geometry (atoms only, not unshared electron pairs): a. $\mathrm{NO}_2{ }^{+}$;
b. $\mathrm{XeF}_4$;
c. $\left(\mathrm{CH}_3\right)_2 \mathrm{TeCl}_2$;
d. $\mathrm{SbCl}_5$;
e. $\mathrm{IF}_5$ :
f. CINO;
g. $\mathrm{XeF}_3{ }^{+}$;
h. $\mathrm{SbCl}_5{ }^{2-}$;
i. $\mathrm{XeO}_4$;
j. $\mathrm{XeF}_5^{+}$;
k. $\left(\mathrm{CH}_3\right)_2 \mathrm{ICl}$;
I. $\mathrm{NCN}^{2-}$.

Lottie Adams

Numerade Educator

01:45

Problem 9

Draw the structure of the following, showing their geometric arrangement of groups (cis or trans, axial or equatorial, etc.): a. $\left(\mathrm{CH}_3\right)_2 \mathrm{TeCl}_2$;
b. $\mathrm{SbBr}_2 \mathrm{~F}_2^{-}$;
c. $\left(\mathrm{CH}_3\right)_2 \mathrm{SbCl}_3$.

Muhammad Ahsan

Numerade Educator

01:29

Problem 10

Consider the following four forms of mercury: $\mathrm{Hg}(\mathrm{I}), \mathrm{Hg}\left(\mathrm{CH}_3\right)_2$ ( $\left.\mathrm{l}\right), \mathrm{HgCl}_2$ (aq), $\mathrm{HgS}(\mathrm{s}$, insoluble). Which form or forms will: a. pass unchanged through the digestive system (digestion requires solubility in lipids or water)? $\mathbf{b}$. be most easily eliminated through the kidneys? c. most readily cross the (nonpolar) blood-brain barrier? $\mathrm{d}$. most readily undergo bioamplification; $e$. be the greatest air-pollution hazard(s)?

Raghvendra Singh

Numerade Educator

03:21

Problem 11

Tell whether the complexes in questions 3,4 , and 5 are likely to be soluble in water; in nonpolar solvents.

Shahina -

Numerade Educator

03:54

Problem 12

Which of the following are chelating ligands? a. $\mathrm{PO}_4{ }^{3-} ; \quad$ b. $\mathrm{Si}_2 \mathrm{O}_7{ }^{6-}$;
c. $\mathrm{CH}_3-\mathrm{O}-\mathrm{CH}_2-\mathrm{O}-\mathrm{CH}_3$;
d. $\left(\mathrm{CH}_3\right)_3 \mathrm{~N}$;
f. $\left[\mathrm{NH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{NH}_3\right]^{2+}$.
e. $\mathrm{N}\left(\mathrm{CH}_2-\mathrm{CO}_2^{-}\right)_3$;

Susan Hallstrom

Numerade Educator

08:48

Problem 13

a. Which of the ligands drawn below are chelating ligands? $\mathbf{b}$. The $\mathrm{Pd}^{2+}$ ion normally has a coordination number of 4. Predict the formula (including overall charge) of the complex ion formed by the $\mathrm{Pd}^{2+}$ ion with each ligand.
FIGURE CANT COPY

Nadia Lara

Numerade Educator

01:13

Problem 14

Below is drawn the structure of a (hypothetical) truly complex complex ion.
FIGURE CANT COPY
a. Write the formulas, including charges if any, of the ligands found in this complex. Underline the donor atoms on each ligand. b. List all chelating ligands in the above complex, if any. Identify each as bidentate, etc. c. List all bridging ligands in the above complex, if any. d. Give the charge of each Mo ion in the above complex, assuming that they either are the same or differ by only one unit of charge. e. Give the coordination number of each Mo ion in the above complex. (They may or may not be the same.)

Catherine Lemar

Numerade Educator

01:50

Problem 15

Some ligands are drawn below. Which of these is/are: a. terdentate ligands; b. macrocyclic ligands; $\mathbf{c}$. ligands that can chelate; d. ligands that can bridge metal ions but not chelate them; $\mathbf{e}$. the ligand that will form the least stable complex with a metal ion?
FIGURE CANT COPY

Marissa Turner

Numerade Educator

06:02

Problem 16

Shown below are some molecules and ions that may be capable of acting as ligands. a. Pick out all that are capable of acting as chelating ligands.
b. Classify each potentially chelating ligand as (potentially) bidentate, tridentate, etc. (Choose the highest possible classification for each.)
FIGURE CANT COPY

April Berlyoung

Numerade Educator

02:27

Problem 17

Below is drawn a neutral coordination compound of the metal niobium, Nb. Assume each bond to $\mathrm{Nb}$ to be a coordinate covalent bond. $\mathrm{a}$. What is the coordination number of $\mathrm{Nb}$ in this complex? $\mathbf{b}$. What is the likely geometric shape about the $\mathrm{Nb}$ atom? c. What are the likely approximate bond angles about the $\mathrm{Nb}$ atom? $\mathbf{d}$. What charge is present on each of the ligands before they coordinate to the $\mathrm{Nb}$ ? e. What charge is present on the $\mathrm{Nb}$ atom before it coordinates all these ligands? $\mathbf{f}$. List all chelating ligands present in this complex. g. List all ambidentate ligands present in this complex.
FIGURE CANT COPY

Catherine Lemar

Numerade Educator

01:11

Problem 18

Give the name of each ligand present in the $\mathrm{Nb}$ complex of the previous question as it will be named in the nomenclature for coordination compounds.

Adriano Chikande

Numerade Educator

03:19

Problem 19

Give the name of each compound given in questions 3,4 , and 5 .

Vasu Makani

Numerade Educator

03:21

Problem 20

Name the complexes given as examples of those used as industrial catalysts (Section 7.2).

Himanshu Kushwaha

Numerade Educator

07:00

Problem 21

Name each of the following complex compounds: a. $\mathrm{Ca}_3\left[\mathrm{VCl}_6\right]_2$;
b. $\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_4(\mathrm{OH})_2\right]\left[\mathrm{AlCl}_4\right] ; \quad$ c. $\mathrm{Cs}\left[\mathrm{V}(\mathrm{CO})_3\left(\mathrm{P}\left(\mathrm{C}_6 \mathrm{H}_5\right)_3\right)_3\right]$;
d. $\mathrm{K}_2\left[\mathrm{ReH}_9\right]$;
e. $\left[\mathrm{Co}(\mathrm{CO})_5\right]\left[\mathrm{BF}_4\right]$;
f. $\mathrm{K}\left[\mathrm{Te}\left(\mathrm{CH}_3\right)_2 \mathrm{Cl}_3\right]$;
g. $\left[\left(\mathrm{CH}_3\right)_4 \mathrm{P}\right]\left[\mathrm{BrF}_4\right]$
h. $\left[\mathrm{Ag}\left(\mathrm{C}_6 \mathrm{H}_6\right)_2\right]$
$\left[\mathrm{Nb}(\mathrm{CO})_6\right]$.

Cameron Oden

Numerade Educator

18:44

Problem 22

Look up one of the following complex compounds in the latest Cumulated Index of Chemical Abstracts. (The booklet How to Search Printed CA will be helpful; note that Chemical Abstracts uses Ewens-Bassett nomenclature.) a. Make a photocopy of the one or two pages of the index that contain all the references to the complex ion and all its salts (or the neutral complex). Mark where these citations begin and where they end. b. Circle the part of these pages that contains the citations of the specific complexes listed below (or their hydrates). c. Look up the same complex ion in Inorganic Syntheses, in the indexes at the ends of volumes 10,20 , and the latest issue. Is a synthesis of your complex ion present? Complex compounds:
(1) $\left[\mathrm{Cr}\left(\mathrm{CH}_3 \mathrm{COCHCOCH}_3\right)_3\right]$ : (2) $\mathrm{K}_3\left[\mathrm{Cr}(\mathrm{SCN})_6\right]$; (3) $\mathrm{K}_3\left[\mathrm{Cr}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]$;
(4) $\left[\mathrm{Cr}\left(\mathrm{NH}_2 \mathrm{CH}_2 \mathrm{CO}_2\right)_3\right]$; (5) $\left[\mathrm{Cr}\left(\mathrm{NH}_2 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{NH}_2\right)_3\right] \mathrm{Cl}_3$;
(6) $\mathrm{Na}_3\left[\mathrm{CrCl}_6\right]$.

Susan Hallstrom

Numerade Educator

07:27

Problem 23

Consider the two complexes (A) dicyanobis(1,2-diaminoethane)platinum(IV) perchlorate and (B) tetramminedicyanoplatinum(IV) sulfate. a. Write the formulas of these two complexes. b. Consider also complex (C), which is drawn below. List these three complexes in order of increasing stability. c. Which complex ( $\mathrm{A}, \mathrm{B}, \mathrm{C}$, or none) contains a chelating ligand? Which complex contains a macrocyclic ligand? Which complex contains a ligand that is bridging?
FIGURE CANT COPY

Qiao Ruan

Numerade Educator

02:56

Problem 24

Calculate the enthalpy changes for the following reactions:
24.1 Diethyl ether + trimethylaluminum $\rightarrow$ diethyl ether : trimethylaluminum
24.2 dimethyl selenide + trimethylaluminum $\rightarrow$ dimethyl selenide: trimethylaluminum
Which Lewis base is more effective at covalent bonding? (Use the $E$ and $C$ parameters to show this.)

Rajesh Singh

Numerade Educator

01:25

Problem 25

Consider the following reaction between different Lewis acid-base adducts:
1-azabicyclo[2.2.1] octane: $\mathrm{SbCl}_5+$ acetone : $\mathrm{Al}\left(\mathrm{CH}_3\right)_3 \rightarrow$
1-azabicyclo[2.2.1]octane: $\mathrm{Al}\left(\mathrm{CH}_3\right)_3+$ acetone : $\mathrm{SbCl}_5$
a. Calculate the enthalpy of formation of each of the adducts from its constituent Lewis acid and base. b. Calculate the overall $\Delta H$ for the above reaction. Does the reaction go to the left or the right?

Cameron Oden

Numerade Educator

05:39

Problem 26

Using Figure 7.11, select a suitable nonaqueous solvent in which to do an acid-base titration of: a. the nonmetal anions listed in Table 5.8; b. the +4 ions in Table 2.2; c. the first ionizable proton of telluric acid; $\mathbf{d}$. the first ionizable proton of selenic acid; $e$. the third ionizable proton of telluric acid.

Ahmed Ali

Numerade Educator

10:40

Problem 27

What solvents would you choose to enhance; a. the acidic properties of acetone, $\left(\mathrm{CH}_3\right)_2 \mathrm{C}=\mathrm{O}$; b. the basic properties of $\mathrm{HNO}_3$; c. the basic properties of $\mathrm{SiH}_4 ;$ d. the acidic properties of $\mathrm{SiH}_4$ ? Write an equation showing a reasonable reaction of each solute with its solvent.

Vishal Sharma

Numerade Educator

01:04

Problem 28

Give plausible products (or just one product) for each of the following reactions, or tell if no reaction is expected. a. $\mathrm{CsCl}+\mathrm{AlCl}_3 \rightarrow$ ?
b. $\mathrm{SiCl}_4+\mathrm{NN}_{\mathrm{N}} \rightarrow$ ? (A conductor of electricity in solution)
c. $\mathrm{PbCl}_4+\mathrm{NN}_{\mathrm{N}} \rightarrow$ ? (A nonconductor of electricity in solution)

Dr. Satish Ingale

Numerade Educator

01:57

Problem 29

Iron forms a number of well-known complexes with the $\mathrm{CN}^{-}$ion. The complexes $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right], \mathrm{K}_3\left[\mathrm{Fe}(\mathrm{CN})_6\right]$, $\mathrm{Fe}\left[\mathrm{Fe}(\mathrm{CN})_6\right]$, and $\mathrm{Fe}_2\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ are not as intensely colored as $\mathrm{KFe}\left[\mathrm{Fe}(\mathrm{CN})_6\right]$, commonly known as Prussian blue.
29.1 Insofar as possible, name each of these five complexes.
29.2 In each complex in which an iron atom is written outside of the brackets, it is also acting as a Lewis acid. What is the Lewis base, and what donor atom(s) is it using? What is the classification of this kind of ligand?
29.3 Explain why Prussian blue is more intensely colored than the other complex compounds.

Varsha Aggarwal

Numerade Educator