1. Coordination Compound
Chapter 12
Coordination Compound

2. Coordination compounds(or complexs) are closely related to the chemistry of transition metals
Main topics:
 Fundamental Concepts of CC
 Valence Bond Theory of CC
 Crystal Field Theory of CC

3. Why Study chemistry of complex
 Transition metals are found in nature
Rocks and minerals contain transition metals
The color of many gemstones is due to the presence of transition metal ions
Rubies(红宝石) are red due to Cr(chromium)
Sapphires(蓝宝石) are blue due to Fe and Ti(titanium)
Many biomolecules contain transition metals that are involved in the functions of these biomolecules
Vitamin B12 contains Co(cobalt)
Hemoglobin, myoglobin, and cytochrome C contain Fe

4. octahedral metal centre
Colour of transition metal complexes
Ruby
Corundum
Al2O3 with Cr3+ impurities
Sapphire
Corundum
Al2O3 with Fe2+ and Ti4+ impurities
octahedral metal centre
coordination number 6
Emerald
Beryl
AlSiO3 containing Be with Cr3+ impurities

5. Why Study chemistry of complex
 Transition metals and their compounds have many useful applications
Fe is used to make steel and stainless steel
Ti is used to make lightweight alloys
Transition metal compounds are used as pigments
TiO2 = white
PbCrO4 = yellow
Fe4[Fe(CN)6]3 (prussian blue, 普鲁士蓝)= blue
Transition metal compounds are used in many industrial processes

6. Why Study chemistry of complex
 To understand the uses and applications of transition metals and their compounds, we need to understand their chemistry.
 Our focus will be on the 4th period transition elements.

7. Fig. 23.1

8. Fig. 23.3

9. Fig. 23.4

10. Periodic Table
d block transition elements
f block transition elements

11. Transition Metals  General Properties
Have typical metallic properties
Not as reactive as Grp. IA, IIA metals
Have high MP’s, high BP’s, high density, and are hard and strong
Have 1 or 2 s electrons in valence shell
Differ in # d electrons in n-1 energy level
Exhibit multiple oxidation states

12. d-Block Transition Elements
VIIIB
IIIB
IVB VB
VIB
VIIB IB
IIB Sc Ti V Cr Mn Fe Co Ni Cu Zn Y Zr Nb Mo Tc Ru Rh Pd Ag Cd La Hf Ta W Re Os Ir Pt Au Hg
Most have partially occupied d subshells in common oxidation states

13. Electronic Configurations
Element Configuration
Sc [Ar]3d14s2
Ti [Ar]3d24s2
V [Ar]3d34s2
Cr [Ar]3d54s1
Mn [Ar]3d54s2
[Ar] = 1s22s22p63s23p6

14. (p. 1012)

15. Aqueous Oxoanions of V, Cr, and Mn in their Highest Oxidation States
Fig 23.5

16. Electronic Configurations
Element Configuration
Fe [Ar] 3d64s2
Co [Ar] 3d74s2
Ni [Ar] 3d84s2
Cu [Ar]3d104s1
Zn [Ar]3d104s2
[Ar] = 1s22s22p63s23p6

17. Transition Metals Characteristics due to d electrons:
Exhibit multiple oxidation states
Compounds typically have color
Exhibit interesting magnetic properties
Paramagnetism(顺磁性)
Ferromagnetism(铁磁性)

18. loss of ns e-s
loss of ns and (n-1)d e-s

19. Electronic Configurations of Transition Metal Ions
 Electronic configuration of Fe2+
Fe – 2e-  Fe2+
[Ar]3d64s [Ar]3d6
valence ns e-’s removed first

20. Fe – 3e-  Fe3+ Co – 3e-  Co3+  Electronic configuration of Fe3+
[Ar]3d64s [Ar]3d5
valence ns e-’s removed first, then n-1 d e-’s
 Electronic configuration of Co3+
Co – 3e-  Co3+
[Ar]3d74s [Ar]3d6
valence ns e-’s removed first, then n-1 d e-’s

21. Concepts of acids and bases
A Brief Review for
Concepts of acids and bases
Historically, chemists have sought to relate the properties of acids and bases to their compositions and molecular structures.

22. ■ Arrhenius concept of acids and bases
— In the 1880s the Swedish chemist Svante
Arrhenius( , 1903 Nobel Prize in chemistry)
linked acid behavior with the presence of H+ ions
and base behavior with the presence of OH-(hydroxyl ion ) ions in aqueous solution. He defined acids as substances that produce H+ ions in water, and base as substances that produce OH- ions in water. Over time his concept of acids and bases came to be stated in the following way: Acids are substances that, when dissolved in water, increase the concentration of H+ ions. Likewise, bases are substances that, when dissolved in water, increase the concentration of OH- ions.
                                             

23. ■ Bronsted concept of acids and bases
— In the 1923 Danish chemist Johannes Bronsted
( ) and English chemist Thomas Lowry
( ) proposed a more general definition
of acids and bases. Their concept is based on the
fact that acid-base reactions involve the transfer
of H+ ions from one substance to another.Bronsted
and Lowry proposed that acids and bases be defin-
ed in terms of their ability to transfer protons.
Their definition is: an acid is a substance(molecule
or ion) that can transfer a proton to another sub-
stance. Likewise, a base is a substance that can
accept a proton.

24. ■ Lewis(1875-1946) concept of acids and bases
— For a substance to be a proton acceptor(a
Bronsted-Lowry base), that substance must
possess an unshared pair of electrons for
binding the proton. For example, NH3 (ammonia)acts as a proton acceptor when it reacts with H+ to form NH4+ (ammonium ion). G.N. Lewis was the first to notice this aspect of acid-base reactions. He proposed a definition of acid and base that emphasizes the shared electron pair. A Lewis acid is defined as an electron-pair acceptor, and a Lewis base is defined as an electron-pair donor. The Lewis definition therefore greatly increases the number of species that can be considered acids.

25.  Transition metals act as Lewis acids
Form complexes/complex ions
Fe3+(aq) + 6CN-(aq)  Fe(CN)63-(aq)
Ni2+(aq) + 6NH3(aq)  Ni(NH3)62+(aq)
Lewis acid
Lewis base
Complex ion
Lewis acid
Lewis base
Complex ion
Complex contains central metal ion bonded to one or more molecules or anions
Lewis acid = metal = center of coordination
Lewis base = ligand = molecules/ions covalently bonded to metal in complex

26.  Transition metals act as Lewis acids
Form complexes/complex ions
Fe3+(aq) CN-(aq)  [Fe(CN)6]3-(aq)
Ni2+(aq) NH3(aq)  [Ni(NH3)6]2+(aq)
Lewis acid
Lewis base
Complex ion
Lewis acid
Lewis base
Complex ion

27. 配位化合物 coordination compounds
★ There is a rich and important chemistry asso-
ciated with such complex assemblies of metals
surrounded by molecules and ions.
Metal compounds of this kind are called:
coordination compounds
配位化合物

28. Addition of base，ammonium hydrate(氨水) to an aqueous solution of Cu2+ ions causes precipitation(沉淀) of Cu(OH)2 (copper hydroxide). When the base is continually added in, the
precipitation will dissolved and form a transparent (透明的) solution with dark blue color. If ethanol(乙醇) is added in this transparent solution, again, the dark blue precipitation appears. chemical analysis tells us the precipitate is Cu(NH3)4]SO4•H2O.

29. ★ Species such as [Cu(NH3)4]2+ that are assemblies of a central metal ion bonded to a group of surrounding molecules or ions are called metal complexes or merely complexes (复合物). If the complex carries a net electric charge, it is generally called a complex ion (复合离子)。
Compounds that contain complexes are known as
coordination compounds ( CC, 配合物)
☞Although transition metals excel in forming coordination compounds, other metals can form them as well.

30. §12.1 fundamental Concepts of CC
1.1 composition of complexes

31. coordination compounds
coordination bond
ionic bond
配位键
离子键
[ Cu ( NH3 )4 ] SO42-
中心原子 配体
内层（inner sphere）
外层（outer sphere）
配合物
coordination compounds
★ coordination molecules have no outer sphere but inner sphere

32. The molecules or ions that surround a metal ion in a complex are called ligands(配体). Ligands may be anions or polar molecules. Some common ligands are water (水), ammonia (氨), hydroxide (氢氧化物), cyanide (氰化物), and chloride (氯化物).

33. Each of these has at least one unshared pair of electrons that can be used to coordinate (form a coordinate covalent bond (配位共价键) to the metal ion). Metal ions can act as Lewis acids, accepting electrons from ligands, which act as Lewis bases. The atom that is bound directly to the metal ion is called the donor atom(供电子原子). It's the atom that donates a lone pair of electrons to the metal ion.

34. [ Cu（NH3）4 ] 2+
[ Fe(H2O) 6]3+
[ SiF6 ] 2- 中心 原子
Cu(Ⅱ)
Fe(Ⅲ)
Si(Ⅳ) 配体
NH3
H2O F- 配位 原子 N O F

35. 中心原子： cations or atoms offering empty orbitals
配 体： the molecules or ions that surround the metal ion in a complex
配位原子： the atoms of ligand bound directly to the metal
（central atom）
（Ligand）
（donor atom）
★ Ligand is from the Latin word ligare, meaning “to bind”

36.  Coordination sphere  Coordination number
Metal and ligands bound to it
 Coordination number
number of donor atoms bonded to the central metal atom or ion in the complex
Most common = 4, 6
Determined by ligands
Larger ligands and those that transfer substantial negative charge to metal favor lower coordination numbers

37.  Ligands classified according to the number of donor atoms Examples
monodentate = 1
bidentate = 2
tetradentate = 4
hexadentate = 6
polydentate = 2 or more donor atoms

38. Coordination Compounds
 Common ligands:
water H - O - H
ammonia NH3
chloride ion Cl -
cyanide ion C N -

39. Monodentate 单齿配体（monodentate ligand )：
— the ligands possess a single donor atom and are able to occupy only one site in a coordination sphere
Monodentate
Examples:
H2O, CN-, NH3, NO2-, SCN-, OH-, X- (halides), CO, O2-
Example Complexes
[Co(NH3)6]3+
[Fe(SCN)6]3-

40. 二齿配体（bidentate ligand )： — the ligands possess two donor atoms
Examples
oxalate ion = C2O42-
ethylenediamine (en) = NH2CH2CH2NH2
ortho-phenanthroline (o-phen)
Example Complexes
[Co(en)3]3+
[Cr(C2O4)3]3-
[Fe(NH3)4(o-phen)]3+
N - CH2- CH2 - N H
Ethylenediamine (en)

41. oxalate ion
(草酸根)
Structures of other bidentate ligands. The coordinating atoms are shown in blue.
Ortho-
phenanthroline
(邻二氮杂菲)
carbonate ion
(碳酸根)
bipyridine
(联二吡啶)

42. Ethylenediamine (en)
N - CH2- CH2 - N H

43. 六齿配体（hexadentate ligand )： — the ligands possess six donor atoms
ethylenediaminetetraacetate (EDTA) = (O2CCH2)2N(CH2)2N(CH2CO2)24-
Example Complexes
[Fe(EDTA)]-1
[Co(EDTA)]-1

44. Coordination Compounds
 Uses for EDTA
Used in food products to complex metals that promote decomposition reactions
Used to remove toxic heavy metals from the body
Used to complex metal ions that inhibit or promote polymerization reactions

45. EDTA

46. Porphine(卟啉), an important chelating agent found in nature
Metalloporphyrin（铁卟啉）

47. Coordination Compounds
Porphyrins are naturally occurring complexes derived from porphin.
Heme (Fe2+)
Chlorophyll (Mg2+)

48. Myoglobin(肌红蛋白), a protein that stores O2 in cells

49. Coordination Environment of Fe2+ in Oxymyoglobin (氧肌红蛋白), and Oxyhemoglobin (氧血红蛋白)

50. Ferrichrome(铁血素) (Involved in Fe transport in bacteria)
Microorganisms secrete siderophore which forms very stable, water-soluble complexes with Fe3+. The resulting complex, ferrichrome, has a net charge of 0 which allows it to pass through the cell wall of the microorganism. In the cell, an enzyme reduces Fe3+ to Fe2+, which forms a weak complex with siderophore so it is released and utilized by the cell. Bacteria use siderophore to obtain iron from human blood, allowing them to reproduce.

51. 常见的单基配体

52. 常见的多基配体

53. Complex charge ☛ The charge on a central metal ion can be
determined in much the same way that oxidation numbers are determined in molecular compounds. It is important to recognize common molecules, to remember that they are neutral, and to know the charges on both monoatomic and polyatomic ions. The sum of charges on the metal ion and the ligands must equal the net charge on the complex.

54. neutral compound [Co(NH3)6]Cl2
Complex charge = sum of charges on the metal and the ligands
[Fe(CN)6]3- +3
6(-1)
Neutral charge of coordination compound = sum of charges on metal, ligands, and counterbalancing ions
neutral compound
[Co(NH3)6]Cl2 +2
6(0)
2(-1)

55. 常见金属离子的配位数

56. Tetrahedral(more common) or square planar
☛ Coordination numbers of 2, 4, and 6 are common. The geometry of a complex is determined in part by its coordination number. (Size of the ligands can also impact the geometry.)
Coordination Number
Geometry 2
Linear 4
Tetrahedral(more common) or square planar 6
Octahedral

57. (p. 1017)

58. Structures of (a) [Zn(NH3)4]2+ and (b) [Pt(NH3)4]2+, illustrating the tetrahedral and square-planar geometries, respectively. These are the two common geometries for complexes in which the metal ion has a coordination number of 4. The shaded surfaces shown in the figure are not bonds; there are included merely to assist in visualizing the shape of the metal complex.

59. Two representations of an octahedral coordination sphere, the common geometric arrangement for complexes in which the metal ion has a coordination number of 6.

60. Attentions: e.g：H2O、 F- e.g：SCN-、 NCS-、 NO2- 、ONO-
 In mono-core coordination compounds, each donor atom can only bind directly to one central atom to form coordination bond.
e.g：H2O、 F-
 Though some ligands have two or more donor atoms, they are still monodentate ligand because only one donor atom can form bond with central atom.
e.g：SCN-、 NCS-、 NO2- 、ONO-

61. — The one formed by central metal atom and monodentate ligand.
1.2 types of CC
1. Simple complex
— The one formed by central metal atom and monodentate ligand.
e.g:
[Cu(NH3)4]SO4、K[Ag(CN)2]、 K2[PtCl4]、etc.

62. 许多水合结晶盐都含有水合配离子.
如: FeCl3· 6H2O为 [Fe(H2O)6]Cl3；
CuSO4·5H2O为 [Cu(H2O)4]SO4·H2O。
H2O分子是单基配体，配位原子是O原子。

63. 2. 螯合物(Chelate compound)
— the ringed coordination compounds formed by metal atom and polydentate
Polydentate ligands (多基配体) tend to coordinate more readily and form more stable complexes than monodentate ligands (单基配体). This phenomenon is known as the chelate effect (螯合效应) .

64. 螯合剂(chelating agents)
— polydentate ligands are also known as chelating agents which are usually organic ligands possessing donor atoms like N、P、O、S.
Cd2+

65. The [CoEDTA]– ion, showing how theEthylene diamine tetraacetate (乙二胺四乙酸) ion is able to wrap around a metal ion, occupying six positions in the coordination sphere. 

66. 3. 特殊配合物 (special complex)
1) 羰合物(carboxide)
— the complex formed when carbon monoxide acts as the ligand
M ← C间的键
M→C间的反馈键

67. 2) 夹心配合物(Sandwich complex)
Fe(C5H5)2
The first sandwich complex discovered was ferrocene (二茂铁). Ferrocene and its derivative are used as additive of rocket fuel, aging agent of silicon resin and rubber and absorbant of ultraviolet light.

68. 3) 原子族状化合物 [Re2Cl8]2－的结构 原子以金属—金属键（M—M）直接结合而形成
原子簇状化合物是指具有两个或两个以上金属
原子以金属—金属键（M—M）直接结合而形成
的化合物，简称簇合物。双核簇合物[Re2Cl8]2－
是最简单的双核簇合物。
[Re2Cl8]2－的结构

69. There are two types of macrocyclic complex:
4) 大环配合物 (marcocyclic complex)
— Ringed coordination compounds formed by metal atom and polydentate ligands with O、N、P、S or As(arsenic) atoms on their ring frameworks
There are two types of macrocyclic complex:
　冠醚（Crown ether）
　穴醚（Hole ether）

70. 1.3 Nomenclature of CC (IUPAC Rules)
 The cation is named before the anion
 When naming a complex:
Ligands are named first
alphabetical order
Metal atom/ion is named last
oxidation state given in Roman numerals follows in parentheses
Use no spaces in complex name
Pentaamminechlorocobalt (III)
[Co(NH3)5Cl]2+
五 氨 氯 钴 (III)

71. Nomenclature of CC (IUPAC Rules)
Ligand
Name
bromide, Br-
bromo
chloride, Cl-
chloro
cyanide, CN-
cyano
hydroxide, OH-
hydroxo
oxide, O2-
oxo
fluoride, F-
fluoro
 The names of anionic ligands end with the suffix -o
-ide suffix changed to -o
-ite suffix changed to -ito
-ate suffix changed to -ato

72. Nomenclature of CC (IUPAC Rules)
Ligand
Name
carbonate, CO32-
carbonato
oxalate, C2O42-
oxalato
sulfate, SO42-
sulfato
thiocyanate, SCN-
thiocyanato
thiosulfate, S2O32-
thiosulfato
Sulfite, SO32-
sulfito

73. Nomenclature of CC (IUPAC Rules)
 Neutral ligands are referred to by the usual name for the molecule
Example
ethylenediamine
Exceptions
water, H2O = aqua
ammonia, NH3 = ammine
carbon monoxide, CO = carbonyl

74. Nomenclature of CC (IUPAC Rules)
 Greek prefixes are used to indicate the number of each type of ligand when more than one is present in the complex
di-, 2; tri-, 3; tetra-, 4; penta-, 5; hexa-, 6
 If the ligand name already contains a Greek prefix, use alternate prefixes:
bis-, 2; tris-, 3; tetrakis-,4; pentakis-, 5; hexakis-, 6
The name of the ligand is placed in parentheses
e.g:
[Co(en)3]Cl3－tris(ethylenediamine)cobalt(III) chloride

75. Nomenclature of CC (IUPAC Rules)
 If a complex is an anion, its name ends with the -ate
appended to name of the metal
e.g:
K4[Fe(CN)6] potassium hexacyanoferrate(II)
[ 六氰合亚铁(II)酸钾]
[CoCl4] tetrachlorocobaltate(II) ion
[四氯合钴(II)酸根离子].

76. Nomenclature of CC (IUPAC Rules)
Transition Metal
Name if in Cationic Complex
Name if in Anionic Complex Sc
Scandium
Scandate Ti
titanium
titanate V
vanadium
vanadate Cr
chromium
chromate Mn
manganese
manganate Fe
iron
ferrate Co
cobalt
cobaltate Ni
nickel
nickelate Cu
Copper
cuprate Zn
Zinc
zincate

77. ★ Some names of coordination compounds
[Co(NH3)4Cl2]Cl:
tetraamminedichlorocobalt(Ⅲ) chloride
[Pt(NH3)2Cl2]:
diamminedichloroplatinum(Ⅱ)
K[Ni(C2O4)2]:
potassium bisoxalatonicketate(Ⅱ)
oxalic acid(草酸)
[Cr (NH3)5H2O](NO3)3:
pentaammineaquachromium (Ⅲ) nitrate

78. Which name is correct for the coordination compound [Fe(en)2Cl2]Cl?
Questions
Which name is correct for the coordination compound [Fe(en)2Cl2]Cl?
A dichlorobisethylenediamineiron(III) chloride B diethylenediaminechlorineiron(I) chloride C iron(III) bisethylenediaminedichloro chloride D iron(III) trichloridebisethylenediamine

79. nomdenclature of complex
配合物的命名
nomdenclature of complex
总称 阴离子在前，阳离子在后
◆ 含配阳离子： 某酸某 某化某 氢氧化某
◆含配阴离子： 某酸某 某酸
◆中性配位分子
[Cu(NH3)4]SO4 硫酸四氨合铜（II）
[Co(NH3)4Cl2]Cl氯化二氯四氨合钴（III）
[Ag(NH3)2]OH氢氧化氨合银(Ⅰ)
K4[Fe(CN)6]六氯合铁（II）酸钾
H2[PtCl6]六氯合铂（IV）酸

80. 注意：配体次序
1)先无机配体后有机配体 )先阴离子后中性分子 )若配体均为阴离子或中性 分子可按配位原子元素符号的英文字母顺序 )同类配体中若配位原子相同，则将含较少原子数的配体排在前面，较多原子数的配体列后 )复杂配体均加圆括号，以免混淆
NH4[Co(NO2)4(en)]
四硝基（乙二胺）合钴（III）酸铵
[Co(NH3)4(NO2)Cl]NO3
硝酸氯硝基四氨合钴（III）
[Co(NH3)3(H2O)Cl2]Cl
氯化二氯三氨水合钴（III）
[Co (NO2)(NH3)4Cl]NO3
硝酸氯硝基四氨合钴（III）

81. [Cu（NH3）4]2+
四氨铜（II）
四氨合铜（II）离子
[CoCl2（NH3）4]+
四氨二氯合钴（III）离子
二氯四氨合钴（III）离子
[Fe（en）3]Cl3
氯化三乙二胺合钴（III）
氯化三（乙二胺）合钴（III）

82. [Ag（NH3）2]OH
氢氧化氨合银
氢氧化二氨合银（I）
H2[PtCl6]
六氯合铂酸（IV）
六氯合铂（IV）酸
[Co（NH3）5（H2O）]2（SO4）3
硫酸一水五氨合钴（III）
硫酸五氨水合钴（III）

83. [Co（NH3）2（en）2]Cl3
氯化二（乙二胺） 二氨合钴（III）
氯化二氨二（乙二胺）合钴（III）
[Ni（CO）4]
四羰基合镍
四羰基合镍（0）

84. [Cu（NH3）4]2+ 加少量NaOH 加少量Na2S 无明显现象 黑色沉淀 Ksp(Cu(OH)2)=5.6×10-20
Cu(OH)2 IP< Ksp
Ksp(CuS )=6.3×10-36
CuS IP > Ksp
说明：
配离子在溶液中仍或多或少的离解出Cu2+

85. 1. Kd and Kf of coordination compounds Formation constant of cc Kf
1.4 Equilibrium of CC
1. Kd and Kf of coordination compounds
配位 kf
Cu2++4NH [Cu(NH3)4]2+
解离 kd
Formation constant of cc Kf
kf=
[Cu(NH3)42+]
[Cu2+][NH3]4 ↗
同类 kf  配合物稳定性
Kf[Ag(CN)2]-=1.3 Kf[Ag(NH3)2]+=1.1107
稳定性 [Ag(CN)2] [Ag(NH3)2]+ 

86. Kf 也叫配合物的稳定常数(KS) 或积累稳定常数(Kβ)
Cu2+＋ NH3
[Cu(NH3)]2+
Kf2
[Cu(NH3)2]2+
[Cu(NH3)]2+ ＋ NH3
Kf3
[Cu(NH3)3]2+
[Cu(NH3)2]2+ ＋ NH3
Kf4
[Cu(NH3)4]2+
[Cu(NH3)3]2+＋ NH3
Kf = Kf1×Kf2×Kf3×Kf4 = 1 Kd
Kf 也叫配合物的稳定常数(KS) 或积累稳定常数(Kβ)

87. Comparison of stability of CC ions: Ks [ Mn+ ] （1）same type：
■Ag(NH3 ) × × 10-9
■ Ag(CN) × × 10-23
（2）different type：
■ CuY × × 10-10
■ Cu(en) × × 10-8

89. 2. Shift of coordination equilibrium
coordination equili- and acid-base equili-
coordination equili- and precipitate equili-
coordination equili- and redox equili-
Common characteristic ：
multiple equilibrium

90. 1) coordination equilibrium and acid-base equilibrium
(1) Effect of Acidity
[Cu（NH3）4] Cu2++4NH3
shift +
4H+
4NH4+
Acidity （pH ）stability  ↘

91. (2) Effect of hydrolysis
[FeF6] Fe F-
[H+]>0.5 mol/L
酸效应 + +
水解效应
6H+
3OH-
Fe(OH)3
6HF
Acidity ↓ stability of CC ↑
一般：在保证不生成氢氧化物沉淀的前提下尽量提高PH值，以保证配合物的稳定性

92. 2) coordination equilibrium and precipitate equilibrium
AgCl
Ag Cl-
KspAgCl=1.8×10-10
+ 2NH3
[Ag(NH3)2]+
Ag NH3
Ks=1.1×107
+ Br-
争取Ag+能力：
Cl- <NH3 < Br- < I- < CN- < S2-
KspAgBr= 5.0×10-13
AgBr
注意：同类型的物质才能由平衡常数作判据

93. 12-7

94. 例：计算298.15K时，AgCl在1L 6molL-1NH3 溶液中的溶解度。
解：先写出此溶液主要存在的平衡反应
1）沉淀平衡：
AgCl（s）
Ag Cl-
KspAgCl=1.77×10-10
2）配位平衡：
Ag NH3
[Ag(NH3)2]+
Ks=1.1×107
两式相加： K
AgCl (s) +2NH3
[Ag(NH3)2]+ + Cl-

95. K
AgCl (s) +2NH3
[Ag(NH3)2]+ + Cl- s
6-2s s s
K =
[Ag(NH3)2+][Cl-]
[NH3]2
[Ag(NH3)2+][Ag+][Cl-]
[Ag+][NH3]2 =
KsKsp = s2
(6-2s)2 K=
KsKsp
= 1.1107 1.77 10-10
所以：
S = 0.24（mol L-1）

96. B K 沉淀溶解条件 Ks Ksp   沉淀生成条件 Ks Ksp  
AgCl (s) + 2NH3
[Ag(NH3)2]+ + Cl-
K =KsKsp
AgBr + 2NH3
[Ag(NH3)2]+ + Br- 1
K′=
KsKsp
沉淀溶解条件
Ks Ksp
 
沉淀生成条件
Ks Ksp
 
当加入配合剂使沉淀溶解时，最有利于沉淀转化为配合物的条件是（ ）
1）Ks大 2）Ks小 3）Ksp大 4）Ksp小
A. 1）2）3） B. 1）3） C. 2）4） D. 4） E. 1）2）3）4） B

97. 若在上述溶液中加入NaBr固体使Br-浓度为0.1 molL-1（忽略加入引起的体积变化）问有无AgBr沉淀生成？
（Ks[Ag（NH3）2]+=1.1107、KspAgCl=1.77 10-10、 KspAgBr=5.35 10-13） 解：
s=0.24（mol L-1）
[Ag（NH3）2]+ + Br-
AgBr + 2NH3
0.24
0.1
6-2  0.24 K= 1 =
5.53 10-13  1.1107
1.7105
KsKsp
Q =
（6-2 0.24）2
0.24 0.1
QK
= 1 103
反应向右进行 有
AgBr生成

98. 例： 在100. 0ml含有过量NH3• H2O的 AgNO3混合溶液中，加入0. 1molL-1NaCl溶液100
例： 在100.0ml含有过量NH3• H2O的 AgNO3混合溶液中，加入0.1molL-1NaCl溶液100.0ml时无AgCl沉淀生成, 计算混合液中NH3的平衡浓度至少为多少？
Ks[Ag(NH3)2]+ = 1.1107、
KspAgCl = 1.8 10-10
解：溶液中的平衡为
Ag + +2NH3
[Ag(NH3)2]+

99. {[Ag(NH3)2]+} Ks = [Ag+]•[NH3]2 ∵无AgCl沉淀 ∴ [Ag+][Cl-] ≤ KspAgCl
[Ag+] ≤ KspAgCl ⁄ [Cl-]
[Cl-]= 0.1×100/200=0.05 molL-1
∴[Ag+] ≤ 1.8  ⁄ 0.05 = 3.6× 10-9molL-1
[Ag(NH3)2]+ = 0.1×100 ⁄ 200－ [Ag+] ≈ 0.05 molL-1
由配位平衡
{[Ag(NH3)2]+}
[Ag+]•[NH3]2
Ks =
得： [NH3]min = 1.12 molL-1

100. {[Ag(NH3)2]+} Ks = [Ag+]•[NH3]2 若用NaBr代替NaCl情况如何？
[Ag+] ≤ KspAgBr ／ [Br-]
[Ag+] ≤ 5.0 10-13 ／ 0.05 = 1.0× 10-11molL-1
{[Ag(NH3)2]+}
[Ag+]•[NH3]2
Ks =
[NH3]min ≈21.3 molL-1
∵ 浓NH3• H2O的浓度仅为15mol L-1
∴上述条件下用NH3• H2O不可能阻止 AgBr沉淀

101. 代入 Ks = {[Zn(NH3)4]2+} ⁄ [Zn2+]• [NH3]4 得： x≈ 3.8×10-3 molL-1
在0.1molL-1 [Zn(NH3)4]2+ 溶液中通入H2S至S2-浓度为:1.0×10-10 molL-1 ,问是否有ZnS沉淀析出？
代入 Ks = {[Zn(NH3)4]2+} ⁄ [Zn2+]• [NH3]4
得： x≈ 3.8×10-3 molL-1
Ks [Zn(NH3)4]2+=5.0108、Ksp ZnS =1.210-23
解：未通H2S前设0.1molL-1 [Zn(NH3)4]2+ 溶液中
[Zn2+] = x molL 则： [NH3] = 4x molL-1
[Zn(NH3)4]2+
Zn2+ +4NH3
[Zn(NH3)4]2+ = 0.1－ x ≈ 0.1 molL-1
通H2S IP = CZn2+ • CS2- = 3.8×10-3 × 1.0×10-10
IP = 3.8×10-13 ＞ Ksp ZnS
∴上述条件下有ZnS沉淀析出

102. 3) coordination equilibrium and redox equilibrium
4Au+O2+2H2O OH-+4Au+ º º
Au+/Au=1.692v 
O2/OH- =0.401v
shift
4Au + O2 + 2H2O + 8CN-
4[Au(CN)2]- + 4OH- º  º
[Au（CN）2]-/Au=-0.574v
O2/OH-=0.401v
forward
2[Au(CN)2]- + Zn
[Zn (CN)4] Au

103. Fe2++1/2 I2 Fe3+ + I- +6F- [FeF6]3- [FeCl4]- Fe3++4Cl- + I-

104. 4) coordination equilibrium and other coordination equilibrium
在某一配位平衡体系中，加入另一种能与中心原子(或配体)形成配合物的配体（或中心原子）配位平衡是否变化，可根据它们的Ks值相对大小(同类型)及计算来判断。

105. 1. 已知Ks[Ag（CN）2]-  Ks[Ag（NH3）2]+，
Questions:
1. 已知Ks[Ag（CN）2]-  Ks[Ag（NH3）2]+， 反应
[Ag（CN）2]- + 2NH [Ag（NH3）2]+ +2CN-将（ ）
A. 正向自发进行 B. 处于平衡状态
C. 逆向自发进行 D. 无法判定 C

106. 2. 在[Cu（NH3）4]SO4溶液中存在平衡 B [Cu（NH3）4]2+ Cu2++4NH3
若向该溶液中分别加入以下试剂，能使平衡右移的
是（ ）
1）盐酸 2）氨水 3）Na2S 4）Na2SO4
A. 1）2）3） B. 1）3）
C. 2）4） D. 4）
E. 1）2）3）4） B

107. ✽ Isomerism of CC
 isomer(异构体) ：Two or more compounds with the same elemental composition but different arrangements of atoms.
— Major Types
 structural isomers
 stereoisomers

108. Structural Isomers
 structural isomers(结构异构体) ： — isomers that have different bonds.
1. Coordination-sphere isomers
differ in a ligand bonded to the metal in the complex, as opposed to being outside the coordination-sphere
Example
[Co(NH3)5Cl]Br vs. [Co(NH3)5Br]Cl

109. [Co(NH3)5Cl]Br vs. [Co(NH3)5Br]Cl
— Consider ionization in water
[Co(NH3)5Cl]Br  [Co(NH3)5Cl]+ + Br-
[Co(NH3)5Br]Cl  [Co(NH3)5Br]+ + Cl-
— Consider precipitation
[Co(NH3)5Cl]Br(aq) + AgNO3(aq)  [Co(NH3)5Cl]NO3(aq) + AgBr(s)
[Co(NH3)5Br]Cl(aq) + AgNO3(aq)  [Co(NH3)5Br]NO3(aq) + AgCl(aq)

110. — differ in the atom of a ligand bonded to the metal in the complex
2. Linkage isomers
— differ in the atom of a ligand bonded to the metal in the complex
Example:
[Co(NH3)5(ONO)]2+ vs. [Co(NH3)5(NO2)]2+
Example:
[Co(NH3)5(SCN)]2+ vs. [Co(NH3)5(NCS)]
Co-SCN vs. Co-NCS

111.  stereoisomers(立体异构体)
— isomers with the same bonds but different spatial arrangements of those bonds.
Geometric isomers
－Differ in the spatial arrangements of the ligands
－Have different chemical/physical
properties different colors, melting
points, polarities, solubilities, reactivities, etc.

113. Geometric Isomers Pt(NH3)2Cl2
cis isomer, 顺式
trans isomer，反式
Pt(NH3)2Cl2

114. [PtCl2(NH3)2]的顺式异构体称为顺铂(cisplatin), 是一个很好的抗癌药物，当它进入人体后，能迅速而又牢固地与DNA(脱氧核糖核酸)结合成为一种隐蔽的cis-DNA加合物，干扰DNA的复制，阻止癌细胞的再生。
[PtCl2(NH3)2]的反式异构体没有抗癌功能。

115. Geometric Isomers
cis isomer
trans isomer
[Co(H2O)4Cl2]+

116. 2. Optical isomers
isomers that are nonsuperimposable mirror images
said to be “chiral” (handed)
referred to as enantiomers
A substance is “chiral” if it does not have a “plane of symmetry”

118. Fig

119. Example 1
mirror plane
cis-[Co(en)2Cl2]+

120. Example 1
rotate mirror image 180°
180 °

121. Example 1
Nonsuperimposable, enantiomers
cis-[Co(en)2Cl2]+

122. Example 2
mirror plane
trans-[Co(en)2Cl2]+

123. Example 2
rotate mirror image 180°
180 °
trans-[Co(en)2Cl2]+

124. Superimposable-not enantiomers
Example 2
Superimposable-not enantiomers
trans-[Co(en)2Cl2]+

125. Properties of Optical Isomers
 Enantiomers
possess many identical properties
solubility, melting point, boiling point, color, chemical reactivity (with nonchiral reagents)
different in:
interactions with plane polarized light
reactivity with “chiral” reagents
Example

126. (vibrates in one plane)
Optical Isomers
polarizing filter
plane polarized light
light source
unpolarized light
(random vibrations)
(vibrates in one plane)

127. Optical Isomers (+) dextrorotatory (right rotation )
(-) levorotatory(left rotation )

128. optically active sample in solution rotated polarized light
polarizing filter
plane polarized light
optically active sample in solution
rotated polarized light

129. optically active sample in solution rotated polarized light
polarizing filter
plane polarized light
optically active sample in solution
Dextrorotatory (d) = right rotation
Levorotatory (l) = left rotation
Racemic mixture = equal amounts of two enantiomers; no net rotation
rotated polarized light

130. §12.2 Valence Bond Theory of Coordination Compounds
— theory of bonds between metal atoms and donor atoms
 主价副价理论(main valence and auxiliary vanlence theory)
 价键理论(valence bond theory)
 晶体场理论(crystal field theory)
 分子轨道理论(molecular orbital theory)
 配位场理论(coordination field theory)

132. The founder coordination compound 1913 Nobel Prize in chemistry
Werner's name will always be associated with the theory of coordination which he established and with his work on the spatial relationships of atoms in the molecule, the foundations of which were laid in the work he did, when he was only 24, for his doctorate thesis in In this work he formulated the idea that, in the numerous compounds of tervalent(三价的) nitrogen, the three valence bonds of the nitrogen atom are directed towards the three corners of a tetrahedron, the fourth corner of this being occupied by the nitrogen atom.
Alfred Werner ( )
The founder coordination compound
1913 Nobel Prize in chemistry

133. In 1891 he had published a paper on the theory of affinity and valence, in which he substituted for Kekulé's conception of constant valence, the idea that affinity is an attractive force exerted from the centre of the atom which acts uniformly towards all parts of the surface of the atom.

134. Some Coordination Compounds of Cobalt Studied by Werner
Werner’s Data*
Traditional Total Free Modern Charge of
Formula Ions Cl Formula Complex Ion .
CoCl3 6 NH [Co(NH3)6]Cl
CoCl3 5 NH [Co(NH3)5Cl]Cl
CoCl3 4 NH [Co(NH3)4Cl2]Cl
CoCl3 3 NH [Co(NH3)3Cl3] . . .

135. 20s of 20 century L· Pauling H· Bethe J· H· Van Vleck
Valence bond theory
1931年
Crystal field theory
1929→1950S

136. Equivalent hybridization
一. Valence Bond Theory
main concepts: －hybridization －coordination bond
 Coordination bond
Central atom
ligand
Equivalent hybridization
Lone electron pair

137. Geometry of NH3

138. 2+
NH3
NH3
Zn2+
NH3
NH3

139. Geometry of [Zn(NH3)4] 2+ 30Zn2+ [Ar]18 4s 4p 3d10 等性sp3杂化
Tetrahedron

140. How to use VSEPR method to predict the molecular shape of PF5 ?
Atoms in the third period and beyond can also use d orbitals to form hybrid orbitals. Mixing one s orbital, three p orbitals, and one d orbital leads to five sp3d hybrid orbitals. These hybird orbitals are directed toward the vertices(顶点) of a trigonal bipyramid(三角双锥). The formation sp3d hybrids is exemplified by the phosphorus (磷) atom in PF5 , phosphorus pentafluoride .
How to use VSEPR method to predict the molecular shape of PF5 ?

141. Similarly, mixing one s orbital, three p orbitals, and two d orbitals gives six sp3d2 hybrid orbitals, which are directed toward the vertices of an octahedron(八面体). The use of d orbitals in constructing hybrid orbitals nicely corresponds to the notion of an expanded valence shell.
 Geometry of coordination compounds depends on the geometry of hybrid orbitals of central atoms !

142. Common hybridization types of metals and the Geometries of the Complexes
Coordination Number Geometry 2
examples:
Linear
[Ag(NH3)2]+
sp hybridization
[Ag(CN)2]-
[Cu(NH3)2]+

143. Common hybridization types of metals and the Geometries of the Complexes
Coordination Number Geometry 3
Example: [Cu(CN)3]2-
sp2 hybridization

144. Common hybridization types of metals and the Geometries of the Complexes
Coordination Number Geometry 4
tetrahedral
Examples: [Zn(NH3)4]2+, [FeCl4]-
sp3
square planar
Example: [Ni(CN)4]2-
dsp2

145. Common hybridization types of metals and the Geometries of the Complexes
Coordination Number Geometry 5
Examples:
[Ni(CN)5]3- [Fe(CO)5]
dsp3

146. Common hybridization types of metals and the Geometries of the Complexes
Coordination Number Geometry 6
octahedral
Examples:
[FeF6] sp3d2
[Fe(CN)6] d2sp3
[Cr(NH3)6]3+ sp3d2

147. Hybrid Orbitals and Bonding in the Tetrahedral [Zn(OH)4]2- ion
30Zn [Ar]3d104s2

148. Hybrid Orbitals and Bonding in the Square Planar [Ni(CN)4]2- Ion
28Ni [Ar]3d84s2

149. Hybrid Orbitals and Bonding in the Octahedral [Cr(NH3)6]3+ Ion
Valence Bond Theory
Hybrid Orbitals and Bonding in the Octahedral [Cr(NH3)6]3+ Ion
24Cr [Ar]3d54s1

150. Factors affecting the geometry of complexs
 Electronic configuration of central atoms (metal atoms)
 electronegativity of donor atoms

151. 1. outer-orbital coordination compound(high-spin complexs)
When the electronegativity of donor atoms like halogen and oxygen is high, it is uneasy for them to lose the lone electron pairs. So the donor atoms can not disorder(push) the valence electrons in metal atoms. Under this circumstance the central atoms only offer their outer-orbitals to form hybrid orbitals, sp,sp2,sp3, sp3d2 ,sp2d3.
Since the electrons in valence shell of the metal atoms are not rearranged, there are relatively more unpaired d electrons in their valence shell. So these complexs are called high-spin complexs.

152. high-spin complexs [FeF6] 3- F- 1s2 2s2 2p6
26Fe [Ar]18 3d6 4s2 → Fe3+ [Ar]18 3d54s0
Equivalent sp3d2 hybridization 4d
3d5
4s0 4p 4d
Sp3d2 hybridization orbital
3d5
high-spin complexs

153. Sp3d2 hybridization orbital
Because bonding orbitals is relatively far away from the nuclei, the bonding electron pairs are not firmly held by the nuclei. So, the bond energy of outer-orbital complexs is low and consequently they are not so stable, having a high solubility in water.

154. 2. inner-orbital coordination compound(low-spin complexs)
When the electronegativity of donor atoms like carbon (CN-) ，nitrogen(-NO2-) is not so high, it is easy for them to lose the lone electron pairs. So the donor atoms can not push the valence electrons into inner orbitals of metal atoms. Under this circumstance the central atoms can offer inner-orbitals to form hybrid orbitals, (n-1)dsp2,(n-1)d2sp3.
Since the electrons in valence shell of the metal atoms are rearranged, there are relatively less unpaired d electrons in their valence shell. So these complexs are called low-spin complexs.

155. [Fe(CN)6] 3-
26Fe [Ar]18 3d6 4s2 → Fe3+ [Ar]18 3d54s0
3d5
4s0 4p
3d5
d2sp3杂化轨道
3d5
low-spin complexs

156. Strength of ligand: d2sp3杂化轨道 3d5
Because bonding orbitals is relatively closer to the nuclei, the bonding electron pairs are firmly held by the nuclei. So, the bond energy of low-orbital complexs is comparatively high and consequently they are stable and have a low solubility in water.
Strength of ligand:
CN- > NO2- > SO32- > en > NH3 > EDTA> H2O > OH- > F - > SCN- > Cl - > Br - > I -
越强越易使中心原子电子重排并成对。

157. Outer-orbital Vs. Inner-orbital hybridization
spd
(n-1)dsp
sp3d2、sp、sp3
dsp2、d2sp3
Inner orbital:
 Requirement for formation of inner-oribtal complexs — The energy released during the bonding between donor atoms and metal atoms is more than that released during formation of outer-orbital complex after offseting the energy for electron pairing.

158. [FeF6] 3- [Fe(CN)6] 3- Fe3+ 18[Ar] 3d5 4s0 4p 4d sp3d2—outer-orbital
High-spin
[Fe(CN)6] 3-
d2sp3—inner-orbital
3d5
low-spin

159. [V(NH3)6]3+ V3+ 18[Ar] 4p 4s 3d2 d2sp3杂化 18[Ar] d2sp3杂化 3d2
Generally, coordination compounds formed by inner orbitals are stabler than those formed by outer orbitals, but the coordination compound formed contains empty (n-1)d orbitals, it will be unstable.
[V(NH3)6]3+
V3+ 18[Ar] 4p 4s
3d2
d2sp3杂化
18[Ar]
d2sp3杂化
3d2

160. 2. Magnetism of complexs
We know that the existence of unpaired electrons in a molecule causes the molecule to exhibit paramagnetism(顺磁性). Paramagnetic substances are attracted by a magnetic field. The magnitude of this attraction can provide evidence of the number of unpaired electrons in the substance.

161. ★未成对 d 电子数与配合物磁矩的关系： B——玻尔磁子(B.M) 1B =9.27×10-24 B.M n 1 2 3 4 5 6 7
（1）[26Fe（H2O）6]3+ =5.9
Fe3+
1s22s22p63s23p6 3d 5
sp3d2 外轨
八面体 n 1 2 3 4 5 6 7 m
1.73
2.83
3.87
4.90
5.92
6.93
7.49
■ 形成外轨型配合物时，一般 n 值不变：
[Fe(H2O)6]2+ 实测=5.70 B
■ 形成内轨型配合物时，一般 n 值减小：
[Fe(CN)6]3+ 实测=2.25B

162. 配合物的电子结构和磁矩

163. E B Cu2+ 1s22s22p63s23p63d9 已知[26Fe（CN）6]3-的磁矩= 3 ，Fe3+采用（ ）
已知[29Cu（NH3）4]2+为内轨型配离子，Cu2+空轨道的杂化类型为（ ）
A. sp3杂化 B. dsp2杂化 C. sp3不等性杂化
D. dsp2不等性杂化 E. d2sp3杂化 F. sp3d2杂化 B
Cu2+
1s22s22p63s23p63d9 4p
dsp2 3d 3d 激发

164. Measurement of the magnetic properties of coordination complexes gives some interesting results. Two complexes containing the cobalt(III) ion exhibit different magnetic properties. The complex ion [Co(NH3)6]3+ is diamagnetic(反磁性的). It contains no unpaired electrons. The complex ion [CoF6]3– is paramagnetic (顺磁性的). In fact, its degree of paramagnetism is such that we know it contains four unpaired electrons.

165. The fact that the cobalt(III) ion has different numbers of unpaired electrons in different compounds indicates that the free ion's electron configuration is not the only determining factor in the number of unpaired electrons in a complex. Crystal-field theory helps explain these observations.

166. Limitations of VB theory
 Assumes bonding is covalent
 Does not account for colour of complexes
 Can predict magnetism wrongly
 Does not account for spectrochemical series

167. §12.3 Crystal-Field Theory
When ligands coordinate to a metal ion, they increase the energies of the metal‘s d orbitals by ligand d-orbital repulsion. Because of their spatial arrangement, the d orbitals do not all experience the same increase in energy. If we consider the formation of an octahedral(八面体的) complex in which the ligands approach the metal ion along the x, y, and z axes, we see that only orbitals that lie along the axes (the dz2 and dx2-y2) are approached directly.

168. (红宝石)

169. Crystal-Field Theory
 Crystal field theory describes bonding in transition metal complexes.
 The formation of a complex is a Lewis acid-base reaction.
 Both electrons in the bond come from the ligand and are donated into an empty, hybridized orbital on the metal.
 Charge is donated from the ligand to the metal.
 Assumption in crystal field theory: the interaction between ligand and metal is electrostatic.
 The more directly the ligand attacks the metal orbital, the higher the energy of the d orbital.

171. - Crystal Field Theory + Octahedral Crystal Field
(-) Ligands attracted to (+) metal ion; provides stability
d orbital e-’s repulsed by (–) ligands; increases d orbital potential energy
ligands approach along x, y, z axes

172. less electrostatic repulsion = lower potential energy
greater electrostatic repulsion = higher potential energy
less electrostatic repulsion = lower potential energy

173. 3.1 Splitting of d orbital of metal atoms
 The complex metal ion has a lower energy than the separated metal and ligands.
 In an octahedral field, the five d orbitals do not have the same energy: three degenerate orbitals are higher energy than two degenerate orbitals.
 The energy gap between them is called , the crystal field splitting energy.

175. Splitting of d-orbital Energies by a Tetrahedral Field and a Square Planar Field of Ligands

176. 3.2 Factors affecting the magnitude of ∆

177. 1. effect of ligands 中心离子相同，配体不同，则由配体所产生的晶体场分裂能力越强，所产生的晶体场场强越大，分裂能越大。

178. 光谱化学序列

180. 2. Effect of metal atoms 配体相同，中心金属离子相同时，金属离子价态越高，分裂能越大。例如：
[Co(H2O)6]3+ △o=18600 cm－1
[Co(H2O)6]2+ △o= 9300 cm－1
[Co(NH3)6]3+ △o= cm－1
[Co(NH3)6]2+ △o= cm－1
配体相同，中心金属离子价态相同且为同族元素时，从上到下分裂能增大。例如：
[Co(NH3)6]3+ △o=23000 cm－1
[Rh(NH3)6]3+ △o= cm－1
[Ir(NH3)6] △o= cm－1

181. 3.3 Electronic Configurations of Transition Metal Complexes
Expected orbital filling tendencies for e-’s:
occupy a set of equal energy orbitals one at a time with spins parallel (Hund’s rule)
minimizes repulsions
occupy lowest energy vacant orbitals first
These are not always followed by transition metal complexes.

182.  d orbital occupancy depends on  and pairing energy, P
e-’s assume the electron configuration with the lowest possible energy cost
If  > P ( large; strong field ligand)
e-’s pair up in lower energy d subshell first
If  < P ( small; weak field ligand)
e-’s spread out among all d orbitals before any pair up

183. d-orbital energy level diagrams octahedral complex

184. d-orbital energy level diagrams octahedral complex

185. d-orbital energy level diagrams octahedral complex

186. d-orbital energy level diagrams octahedral complex
low spin
 > P
high spin  < P

187. d-orbital energy level diagrams octahedral complex
low spin
 > P
high spin  < P

188. d-orbital energy level diagrams octahedral complex
low spin
 > P
high spin  < P

189. d-orbital energy level diagrams octahedral complex
low spin
 > P
high spin  < P

190. d-orbital energy level diagrams octahedral complex

191. d-orbital energy level diagrams octahedral complex

192. d-orbital energy level diagrams octahedral complex

193. Electronic Configurations of Transition Metal Complexes
 Determining d-orbital energy level diagrams:
determine oxidation # of the metal
determine # of d e-’s
determine if ligand is weak field or strong field
draw energy level diagram

194. High-spin and low-spin complex ions of Mn2+

195. High spin weak-field ligand Low spin strong-field ligand
Orbital Occupancy
for High- and Low-
Spin Complexes of
d4 Through d7 Metal
Ions

196. Hemoglobin and the Octahedral Complex in Heme

197. 3.4 Application of crystal field theory
Crystal field theory can offer a good explanation of many properties of transition metal, such as stability、spectrum、and magnetism.

198. Properties of Transition Metal Complexes
usually have color
dependent upon ligand(s) and metal ion
many are paramagnetic
due to unpaired d electrons
degree of paramagnetism dependent on ligand(s)
[Fe(CN)6]3- has 1 unpaired d electron
[FeF6]3- has 5 unpaired d electrons

199.  Crystal Field Theory Can be used to account for
Colors of transition metal complexes
A complex must have partially filled d subshell on metal to exhibit color
A complex with 0 or 10 d e-s is colorless
Magnetic properties of transition metal complexes
Many are paramagnetic
# of unpaired electrons depends on the ligand

200. 1. Account for the color of complexs
 Compounds/complexes that have color:
absorb specific wavelengths of visible light (400 –700 nm)
wavelengths not absorbed are transmitted
color observed = complementary color of color absorbed

201. Visible Spectrum wavelength, nm 400 nm 700 nm higher energy
(Each wavelength corresponds to a different color)
400 nm
700 nm
higher energy
lower energy
White = all the colors (wavelengths)

202. absorbed color
observed color

203. Relation Between Absorbed and Observed Colors
Absorbed Observed
Color  (nm) Color  (nm)
Violet Green-yellow
Blue Yellow
Blue-green Red
Yellow-green Violet
Yellow Dark blue
Orange Blue
Red Green

204. Color & Visible Spectra

205. Color& Spectra
 The plot of absorbance versus wavelength is the absorption spectrum.
—For example, the absorption spectrum for [Ti(H2O)6]3+ has a maximum absorption occurs at 510 nm (green and yellow).
—So, the complex transmits all light except green and yellow.
—Therefore, the complex appears to be purple.

206.  Absorption of UV-visible radiation by atom, ion, or molecule:
Occurs only if radiation has the energy needed to raise an e- from its ground state to an excited state
i.e., from lower to higher energy orbital
light energy absorbed = energy difference between the ground state and excited state
“electron jumping”

207. green light observed
red light absorbed
white light
Absorption raises an electron from the lower d subshell to the higher d subshell.
For transition metal complexes,  corresponds to energies of visible light.

208. Many coordination compounds exhibit vivid colors
Many coordination compounds exhibit vivid colors. Pigments in paint are often coordination complexes, as are the colorants（着色剂） in stained glass（彩色玻璃）. The colors exhibited by coordination compounds can be explained in terms of the electron configurations of their central metal ions.
It is generally necessary for a metal ion to have a partially filled d subshell for it to be colored. In fact, most transition-metal ions have a partially filled d subshell. Compounds of metal ions with empty d subshells, such as Al3+ and Ti4+ are typically colorless. Compounds of metal ions with completely filled d subshells, such as Zn2+, also tend to be colorless.

209. Objects and substances appear colored by virtue of reflection or absorption of visible light. An opaque （不透明的） object may appear yellow because it reflects only yellow light and absorbs all other colors; or, it may appear yellow because it absorbs just the complementary color （补色） of yellow, which is violet A translucent （半透明的） material may transmit only green light, or it may transmit all colors but red, the complementary color of green. Either way, it will appear green to our eyes.
violet

210.  Different complexes exhibit different colors because:
color of light absorbed depends on 
larger  = higher energy light (Shorter wavelengths) absorbed
smaller  = lower energy light(Longer wavelengths) absorbed
magnitude of  depends on:
ligand(s)
metal

211. red light absorbed (lower energy light)
green light observed
red light absorbed (lower energy light)
white light
[M(H2O)6]3+

212. Colors of Transition Metal Complexes
white light
orange light observed
blue light absorbed (higher energy light)
[M(en)3]3+

213. 配离子显色的原因如下：
如果配合物中心离子的t2g轨道和eg轨道没有充满，通过吸收可见光（或紫外光）区的某一波长的光波，就可以使d电子从t2g轨道跃迁到eg轨道，我们称之为 d-d 跃迁。
包含所有可见光波长的白光，照射配离子的水溶液时，因为配离子发生d—d跃迁而吸收了部分波长，透过余下的光波，溶液便呈现出不同的颜色。
因为产生d—d跃迁所吸收的能量与配离子的分裂能有关，所以分裂能不同的配离子会显示不同的颜色。

214. octahedral metal centre
Colour of transition metal complexes
Ruby
Corundum
Al2O3 with Cr3+ impurities
(红宝石)
(刚玉)
Sapphire
Corundum
Al2O3 with Fe2+ and Ti4+ impurities
(蓝宝石)
octahedral metal centre
coordination number 6
Emerald
Beryl
AlSiO3 containing Be with Cr3+ impurities
(绿宝石,翡翠)
(绿玉)

215. ∆4 ∆3 ∆2 ∆1 green violet yellow yellow red yellow violet violet
The wavelength of light absorbed depends on the size of the energy gap, ∆ , between lower- and higher-energy d orbitals. The size of ∆ depends in part on the identity of the ligands coordinating to the metal ion. Figure below shows a series of four chromium(III) complexes, each with a different ∆ value. ∆4 ∆3 ∆2 ∆1
24Cr3+ 3d3
green
violet
yellow
yellow
red
yellow
violet
violet

216. 例如，[Ti(H2O)6]3+的分裂能△o =20400 cm―1对波长为490 nm（波数为20400 cm―1）的光有最大吸收峰，相当于吸收了蓝绿色的光，该配合物呈现出紫红色。

217. The energy gap between the three lower-energy d orbitals and the two higher-energy d orbitals is such that visible light causes this electron promotion. Thus, a particular wavelength of visible light is absorbed, giving a coordination complex its characteristic color. The gap between lower- and upper-level d orbitals in the [Ti(H2O)6]3+ ion is of the magnitude that light of 510 nm wavelength promotes an electron. Absorption of this wavelength of light (510 nm is a green wavelength) gives the ion its characteristic red color.

218. 22Ti
[Ar]3d24s2
Ti: titanium
22Ti3+
[Ar]3d14s0
[Ti(H2O)6]3+, 红色

219. ★ 因为Zn2+为d10构型，不会发生d—d跃迁， 所以[ Zn(H2O)6]2+离子为无色溶液。
“光谱化学序列”就是利用这一原理测出来的。
需要指出的是，过渡金属离子颜色不一定都
是d—d跃迁的结果。

220. Color of a complex depends on: (i) the metal and (ii) its oxidation state.
Pale blue [Cu(H2O)6]2+ can be converted into dark blue [Cu(NH3)6]2+ by adding NH3(aq).
A partially filled d orbital is usually required for a complex to be colored.
So, d 0 metal ions are usually colorless. Exceptions: MnO4- and CrO42-.
Colored compounds absorb visible light.
The color our eye perceives is the sum of the light not absorbed by the complex.

221. 2. Account for the stability of complexs
1．配合物稳定性的示方法
在[Cu(NH3)4]SO4溶液中，实际上存在着如下平衡：
[Cu(NH3)4]2+ ⇌ Cu2++4NH3
Cu2++4NH3 ⇌ Cu(NH3)4]2+

222. [Cu(NH3)4]2+ ⇌ Cu2++4NH3
Cu2++4NH3 ⇌ Cu(NH3)4]2+
前者是配离子的解离反应，后者则是配离子的生成反应。与之相应的标准平衡常数分别为叫做配离子的解离常数(dissociation constant)和生成常数(formation constant)，分别用符号Kd和Kf 表示。 Kd是配离子不稳定性的量度，对相同配位数的配离子来说， Kd越大，表示配离子越易解离。

223. Kf是配离子稳定性的量度， Kf值越大，表示该配离子在水中越稳定，因而Kd和Kf又分别称为不稳定常数(unstable constant)和稳定常数(stable costant)。
显然任何一个配离子的与互为倒数关系：
Kd × Kf = 1

224. 在溶液中配离子的生成是分步进行的，每一步都有一个对应的稳定常数，我们称它为逐级稳定常数(stepwise stable constants)（或分步稳定常数）。逐级稳定常数越大表示该级配合物越稳定，
例如：
Cu2+ + NH3 ⇌ [Cu(NH3)]2+

225. [Cu(NH3)]2+ + NH3 ⇌ [Cu(NH3)2]2+ K20 = 10 3.67
同理有：
[Cu(NH3)]2+ + NH3 ⇌ [Cu(NH3)2]2+ K20 =
[Cu(NH3)2]2+ + NH3 ⇌ [Cu(NH3)3] K30 =
[Cu(NH3)3]2+ + NH3 ⇌ [Cu(NH3)4] K40 =
多配体配离子的总稳定常数（或累积稳定常数）等于逐级稳定常数的乘积：
[Cu] NH3 ⇌ [Cu(NH3)4]2+

226. 一些常见配离子的稳定常数

227. d6 ☛ 在晶体场中，中心离子的d电子从假如未分 裂的d轨道（能量为Es的d轨道）进入分裂后 的d轨道所产生的能量下降低值，称为晶体
场稳定化能(crystal field stability energy)。 d6

228. 除了Ni2+和Cu2+的顺序反常外，弱场中配离子的稳定性顺序与CFSE顺序基本一致，即CFSE愈大，配合物愈稳定。Cu2+的稳定性大于Ni2+是由于Cu2+的八面体配离子产生了杨-泰勒效应的结果.

229. 3. Account for the magnetism of complexs
在价键理论中，需要借助配离子的磁性实验数据推测中心离子d 轨道中的未成对电子数，从而判断中心离子属于何种杂化类型，该配合物属于何种配合物。
在晶体场理论中，只要知道分裂能（△o）和电子成对能（P）数据，就可以判断该配离子属于强场或弱场离子，并进一步写出d电子在t2g轨道和eg轨道上的分布情况，判断成单电子数，并利用公式3-12计算出该配离子磁矩的理论值。

230. Magnetism
Many transition metal complexes are paramagnetic (i.e. they have unpaired electrons).
There are some interesting observations. Consider a d6 metal ion:
[Co(NH3)6]3+ has no unpaired electrons, but [CoF6]3- has four unpaired electrons per ion.
We need to develop a bonding theory to account for both color and magnetism in transition metal complexes.