Advanced Inorganic Chemistry
|
|
- Audrey Butler
- 5 years ago
- Views:
Transcription
1 Advanced Inorganic Chemistry
2 Orgel Diagrams
3 Correlation of spectroscopic terms for d n configuration in O h complexes Atomic Term Splitting of the weak field d n ground state terms in an octahedral ligand field Number of states Terms in O h Symmetry S 1 A 1g P 3 T 1g D 5 T 2g + E g F 7 T 1g + T 2g + A 2g Ground state determined by inspection of degeneracy of terms for given d n
4
5 Orgel Diagrams 2 E g 2 D 2 T 2g d 1 o 3 P 3 F 3 T 1g (P) 4 T 1g (P) 3 A 4 2g P 4 T 5 T 2g 1g 3 T 2g 4 F 4 T 5 2g D 3 T 5 1g E g o 4 o A 2g d 2 d3 o d 4 2 T 2g 2 E g 3 T 1g 3 T 2g 3 T 1g 3 A 2g 3 T 1g 3 T 1g (P) Ti 3+ V 2+ Cr 3+ Mn 3+
6 The d-d bands of the d 2 ion [V(H 2 O) 6 ] 3+
7 The Tanabe-Sugano diagram
8
9 Correlation diagrams between energies of atomic and molecular terms can drawn as so-called Tanabe-Sugano diagrams for each electron configuration of free ions. Y. Tanabe, s. Sugano; J. Phys. Soc, Jap., 9, 753 (1954) Energy values in a Tanabe-Sugano diagram are only given relative to the ground state (x-axis).
10 The simple correlation diagram had multiples of B (the Racah parameter) on the energy axis to denote the relative energies of the atomic terms. In the Tanabe-Sugano diagrams, the energy axis has units of E/B. The x-axis has units of o/b. Each Tanabe-Sugano diagram is given for only one specific B/C ratio (the best value). For example, the Tanabe-Sugano diagram for d3 complexes is given for C=4.5 B. non-crossing rule: Terms of the same symmetry cannot cross and will repel each other.
11 Racah Inter-electronic Repulsion Parameters (B, C) 1 S 1 G 3 P 1 D 3 F E( 3 P) = A+7B E( 1 D) = A - 3B + 2C E( 3 F) = A - 8B d 2 3 F 3 P 3 F 1 D = 15B = 5B + 2C
12 Evidence for covalent bonding in metal-ligand interactions The Nephelauxetic Effect ( cloud expansion ) Reduction in electron-electron repulsion upon complex formation Racah Parameter, B: electron-elctronic repulsion parameter B o is the inter- electronic repulsion in the gaseous M n+ ion. B is the inter- electronic repulsion in the complexed ML x n+ ion. The smaller values for B in the complex compared to free gaseous ion is taken as evidence of smaller inter-electronic repulsion in the complex due to a larger molecular orbital on account of overlap of ligand and metal orbital, i.e. evidence of covalency (cloud expansion ). Nephelauxetic Ratio, β = B B o
13 Nephelauxetic Ligand Series I < Br < CN < Cl < NCS < C 2 O 2-4 < en < NH 3 < H 2 O < F Small β Covalent Nephelauxetic Metal Series Large β Ionic NEPHELAUXETIC ADVANCED INORGANIC EFFECT CHEMISTRY Pt 4+ < Co 3+ < Rh 3+ ~Ir 3+ < Fe 3+ < Cr 3+ < Ni 2+ < V 4+ < Pt 2+ ~ Mn 2+ Small β Large overlap Covalent Large β Small overlap Ionic
14 Empirical Racah parameters, h, k β = 1 [h(ligand) x k(metal)] Cr(NH 3 ) 6 3+ Cr(CN) 6 3- β = 1 hk β = 1 hk β = 1 (1.4)(0.21) = β = 1 (2.0)(0.21) = B o - B = h ligands x k metal ion B o
15 Typical o and» max values for octahedral (ML 6 ) d-block metal complexes Complex o cm -1 ~» max (nm) Complex o cm -1» max (nm) [Ti(H 2 O) 6 ] 3+ 20, [Fe(H 2 O) 6 ] 2+ 9, [V(H 2 O) 6 ] 3+ 20, [Fe(H 2 O) 6 ] 3+ 13, [V(H 2 O) 6 ] 2+ 12, [Fe(CN) 6 ] 3-35, [CrF 6 ] 3-15, [Fe(CN) 6 ] 4-33, [Co(H 2 O) 6 ] 3+, l.s. 20, [Fe(C 2 O 4 ) 3 ] 3-14, [Cr(H 2 O) 6 ] 2+ 14, [Co(CN) 6 ] 3- l.s. 34, [Cr(H 2 O) 6 ] 3+ 17, [Co(NH 3 ) 6 ] 3+ l.s. 22, [Cr(NH 3 ) 6 ] 3+ 21, [Ni(H 2 O) 6 ] 2+ 8, [Cr(en) 3 ] 3+ 21, [Ni(NH 3 ) 6 ] 2+ 10, [Cr(CN) 6 ] 3-26, [Ni(en) 3 ] 2+ 11,
16 Example of the use of Tanabe-Sugano Diagrams For the use of Tanabe-Sugano diagrams we will be using Tables 17.1 and 17.2 (see the resources for Test 3). 10 Dq o = f x g. Let us consider the complex Co(NH 3 ) The oxidation state of the cobalt is +2, so the the metal isconsidered a d 7. To figure out 10 Dq o (also known as delta octahedral), from Table 17.1 we multiply f from the ligand column by g from the metal ion column. This gives 1.25 x 9000 = 11,250 cm -1 which is the size of 10 Dq o. The next step is to determine the reduced Racah parameter for the complex. The reduced Racah parameter is called beta. beta=(b complex )/(B free ion ) = 1 - h. k The quantities h and k can also be found in Table 17.1 for many ligands and metal centers. For the current example beta=(b complex )/(B free ion ) = 1 - h. k = 1 - (1.4)(0.09) = 0.874
17 From this it easy to rearrange things to get B complex and use the value of B free ion for Co 2+ from Table 17.2 (beta)(b free ion ) = B complex = (0.874)(971 cm -1 ) = 849 cm -1 To use a Tanabe-Sugano diagram, you mustdivide the value of 10 Dq o B complex. (10 Dq o )/B complex = 11,250 cm -1 /849 cm -1> = This is the value that will be read on the x-axis of the Tanabe-Sugano diagram. Using the correct Tanabe-Sugano diagram (d 7 in this case) is critical. Looking at the Tanabe- Sugano diagram quickly reveals that the term symbol for a free Co 2+ ion is 4 F. Also looking at the Tanabe Sugano diagram, we notice that the value of is to the left of the point of inflection. This means that the complex Co(NH 3 ) 6 2+ is a high spin complex (if the value was to the left of the inflection point, it would be a low spin complex). Spin allowed ttransitions from the ground state will therefore all be from quadruplet to quadruplet. The allowed transitions are: by 4 T 1g -----> 4 T 2g 4 T 1g -----> 4 T 1g 4 T 1g -----> 4 A 2g
18 Reading straight up from on the x-axis until it crosses the line corresponding to the other quadruplet states will give us E/B complex on the y- axis. 4 T 1g -----> 4 T 2g E/B complex = T 1g -----> 4 T 1g E/B complex = T 1g -----> 4 A 2g E/B complex = 25.6 To get the energy of the transitions in cm -1, each of these must be multiplied by B complex 4 T 1g -----> 4 T 2g E/B complex =12.4 ; 12.4 x 849 cm -1 = 10,528 cm -1 4 T 1g -----> 4 T 1g E/B complex = 25.6; 25.6 x 849 cm -1 = 21,734 cm -1 4 T 1g -----> 4 A 2g E/B complex = 25.6, 25.6 x 849 cm -1 = 21,734 cm -1
19 The last step is to convert the wave number (reciprocal centimeters, cm -1 ) to namometers 4 T 1g -----> 4 T 2g 10,528 cm -1 ; 1/(10,528 cm -1 ) = 9.50 x 10-5 cm; (9.50 x 10-5 cm)(10 7 nm/cm) = 950 nm 4 T 1g -----> 4 T 1g 21,734 cm -1 ; 1/(21,734 cm -1 ) = 4.60 x 10-5 cm; (4.60 x 10-5 cm)(10 7 nm/cm) = 460 nm 4 T 1g -----> 4 A 2g 21,734 cm -1 ; 1/(21,734 cm -1 ) = 4.60 x 10-5 cm; (4.60 x 10-5 cm)(10 7 nm/cm) = 460 nm All of these transitions are d-d transitions. The first transition at 950 nm is in the near IR just above the red portion of the visible spectrum. The two transitions at 460 nm correspond to an absorbance of blue (very slightly shaded to green) light in the visible spectrum.
20 Use of Tanabe-Sugano Diagrams for Interpretation of UV/Visible Absorption Spectra of Complexes d 3
21
22
23
24
25 26.5
26 26.5
27
28
29 Charge-Transfer Spectra
30 Charge Transfer Transitions As well as d-d transitions, the electronic spectra of transition metal complexes may 3 others types of electronic transition: Ligand to metal charge transfer (LMCT) Metal to ligand charge transfer (MLCT) Intervalence transitions (IVT) All complexes show LMCT transitions, some show MLCT, a few show IVT
31 Ligand to Metal Charge Transfer These involve excitation of an electron from a ligand-based orbital into a d- orbital O O O M O visible light This is always possible but LMCT transitions are usually in the ultraviolet They occur in the visible or near-ultraviolet if metal is easily reduced (for example metal in high oxidation state) ligand is easily oxidized O O O M O If they occur in the visible or near-ultraviolet, they are much more intense than d-d bands and the latter will not be seen
32 Ligand to Metal Charge Transfer They occur in the visible or near-ultraviolet if metal is easily reduced (for example metal in high oxidation state) d 0 TiO 2 Ti 4+ VO 4 3- V 5+ Cr 6+ Mn 7+ CrO 4 MnO 4 in far UV ~39500 cm -1 ~22200 cm -1 ~19000 cm -1 white white yellow purple 2- - more easily reduced
33 Metal to Ligand Charge Transfer They occur in the visible or near-ultraviolet if metal is easily oxidized and ligand has low lying empty orbitals N N N N M N N N N N N M = Fe 2+, Ru 2+, Os 2+ Sunlight excites electron from M 2+ (t 2g ) 6 into empty ligand π* orbital method of capturing and storing solar energy
34 Intervalence Transitions Complexes containing metals in two oxidation states can be coloured due to excitation of an electron from one metal to another Prussian blue contains Fe 2+ and Fe 3+ Colour arises from excitation of an electron from Fe 2+ to Fe 3+
35 (p) (s) (d) 3) Charge transfer bands Similar to d-d transitions, charge-transfer (CT) transitions also involve the metal d-orbitals. CT bands are observed if the energies of empty and filled ligand- and metal-centered orbitals are similar. The direction of the electron transfer is determined by the relative energy levels of these orbitals: i) ligand-to-metal charge transfer (LMCT) like in MnO 4-, CrO 4 2- etc. or ii) metal-to ligand charge transfer (MLCT) like in [Fe(bpy) 3 ] 2+. The simplified diagrams below are the modified versions of what we had in Lecture 26. Bold arrows show possible CT transitions. t 2 a 1 e t 2 Mn VII 4 O 2- d 0 3t 2 2a 1 2t e t t 2 t 1 (n) t 2 a 1 (σ) ο Fe II d 6 e g t 2g 3 bpy π-go's 3t 2g N N e g 2t 2g bpy = t 2g (π*) t 2g (π) 1a 1 1t 2g
36 Metal character Ligand character Charge transfer spectra Ligand character LMCT Metal character MLCT Much more intense bands
37 Charge-Transfer Spectra It is extremely common for coordination compounds also to exhibit strong charge-transfer absorptions, typically in the ultraviolet and/or visible portions of the spectrum These absorptions may be much more intense than d-d transitions (which for octahedral complexes usually have µ values of 20 L mol -1 cm -1 or less): molar absorptivities of 50,000 L mole -1 cm- 1 or greater are not uncommon for these bands Such absorption bands involve the transfer of electrons from molecular orbitals that are primarily ligand in character to orbitals that are primarily metal in character (or vice versa)
38 Charge-Transfer Spectra For example, consider an octahedral d 6 complex with Ã-donor ligands The possibility exists that electrons can be excited, not only from the t 2g level to the e g but also from the Ãorbitals originating from the ligands to the e g The latter excitation results in a charge-transfer transition; it may be designated as charge transfer to metal (CTTM) or ligand to metal charge transfer (LMCT) This type of transition results in formal reduction of the metal. A CTTM excitation involving a cobalt (III) complex, for example, would exhibit an excited state having cobalt (II)
39 Charge-Transfer Spectra Similarly, it is possible for there to be charge transfer to ligand (CTTL), also known as metal to ligand charge transfer (MLCT), transitions in coordination compounds having À-acceptor ligands In these cases, empty À* orbitals on the ligands become the acceptor orbitals on absorption of light CTTL results in oxidation of the metal; a CTTL excitation of an iron(iii) complex would give an iron(iv) excited state. CTTL most commonly occurs with ligands having empty À* orbitals, such as CO, CN -, SCN -, bipyridine, and dithiocarbamate (S 2 CNR 2- )
40 Charge-Transfer Spectra In complexes such as Cr(CO) 6 which have both Ã-donor and À-acceptor orbitals, both types of charge transfer are possible It is not always easy to determine the type of charge transfer in a given coordination compound Many ligands give highly colored complexes that have a series of overlapping absorption bands in the ultraviolet part of the spectrum as well as the visible In such cases, the d-d transitions may be completely overwhelmed and essentially impossible to observe
41 Charge-Transfer Spectra Finally, the ligand itself may have a chromophore and still another type of absorption band an intraligand band, may be observed These bands may sometimes be identified by comparing the spectra of complexes with the spectra of free ligands However, coordination of a ligand to a metal may significantly alter the energies of the ligand orbitals, and such comparisons may be difficult, especially if charge-transfer bands overlap the intraligand bands Also, it should be noted that not all ligands exist in the free state: some ligands owe their existence to the ability of metal atoms to stabilize molecules that are otherwise highly unstable
42 3)CN - Example: a) HOMO = σ-bonding electron pair donor to metal ion b) LUMO = π-bonding electron pair acceptor from metal ion c) The π* orbitals are higher in energy than the metal t 2g orbitals having the correct symmetry to overlap with d) The energy match is good enough for overlap to occur e) π-bonding results
43 i. 3 new bonding t 2g MO s receive the d-electrons ii. 3 new antibonding t 2g * MO s formed iii. The e g * MO s from the σ-bond MO treatment are nonbonding iv.ligands like this increase o by lowering the energy of t 2g MO s favoring low spin complexes v. CN - is a strong field ligand vi. Metal to Ligand (M L) or π- back bonding to π-acceptor ligand vii. Transfer of electron density away from M + stabilizes the complex over σ-bonding only
44 4)F - example a) Filled p-orbitals are the only orbitals capable of π-interactions i) 1 lone pair used in σ-bonding ii) Other lone pairs π-bond b) The filled p-orbitals are lower in energy than the metal t 2g set c) Bonding Interaction i. 3 new bonding MO s filled by Fluorine electrons ii. 3 new antibonding MO s form t 2g * set contain d-electrons iii. o is decreased (weak field) d) Ligand to metal (L M) π-bonding i. Weak field, π-donors: F, Cl, H 2 O ii. Favors high spin complexes
45
46 END
47
48
49
50
51
52
53
54
Perhaps the most striking aspect of many coordination compounds of transition metals is that they have vivid colors. The UV-vis spectra of
1 Perhaps the most striking aspect of many coordination compounds of transition metals is that they have vivid colors. The UV-vis spectra of coordination compounds of transition metals involve transitions
More informationElectronic Spectra of Coordination Compounds
Electronic Spectra of Coordination Compounds Microstates and free-ion terms for electron configurations Identify the lowest-energy term Electronic Spectra of Coordination Compounds Identify the lowest-energy
More information6.2. Introduction to Spectroscopic states and term symbols
Chemistry 3820 Lecture Notes Dr. M. Gerken Page62 6.2. Introduction to Spectroscopic states and term symbols From the number of absorption bands we have already seen that usually more d-d transitions are
More informationTransition Metal Complexes Electronic Spectra 2
Transition Metal Complexes Electronic Spectra 2 Electronic Spectra of Transition Metal Complexes Cr[(NH 3 ) 6 ] 3+ d 3 complex Molecular Term Symbols Quartet states Doublet state Different Ways of Transitions
More informationHow to identify types of transition in experimental spectra
17 18 19 How to identify types of transition in experimental spectra 1. intensity 2. Band width 3. polarization Intensities are governed by how well the selection rules can be applied to the molecule under
More informationElectronic Spectra of Complexes
Electronic Spectra of Complexes Interpret electronic spectra of coordination compounds Correlate with bonding Orbital filling and electronic transitions Electron-electron repulsion Application of MO theory
More informationDr. Fred O. Garces Chemistry 201
23.4 400! 500! 600! 800! The relationship between Colors, Metal Complexes and Gemstones Dr. Fred O. Garces Chemistry 201 Miramar College 1 Transition Metal Gems Gemstone owe their color from trace transition-metal
More informationlight is absorbed, the complex appears green; If
Color of Transition Metal Complexes The variety of color among transition metal complexes has long fascinated the chemists. For example, aqueous solutions of [Fe(H 2 O) 6 ] 3+ are red, [Co(H 2 O) 6 ] 2+
More informationRDCH 702 Lecture 4: Orbitals and energetics
RDCH 702 Lecture 4: Orbitals and energetics Molecular symmetry Bonding and structure Molecular orbital theory Crystal field theory Ligand field theory Provide fundamental understanding of chemistry dictating
More informationI. Multiple Choice Questions (Type-I) ] 2+, logk = [Cu(NH 3 ) 4 O) 4. ] 2+, logk = 8.9
Unit 9 COORDINATION COORDINA COMPOUNDS I. Multiple Choice Questions (Type-I) 1. Which of the following complexes formed by Cu 2+ ions is most stable? (i) Cu 2+ + 4NH 3 [Cu(NH 3 ] 2+, logk = 11.6 (ii) Cu
More informationBonding in Octahedral and Tetrahedral Metal Complexes. Predict how the d orbitals are affected by the Metal- Ligand Bonding
Bonding in Octahedral and Tetrahedral Metal Complexes 327 Molecular Orbital Theory and Crystal Field/Ligand Field Theory Predict how the d orbitals are affected by the Metal- Ligand Bonding d z 2, d x
More informationChm 363. Spring 2017, Exercise Set 3 Transition Metal Bonding and Spectra. Mr. Linck. Version 1.5 March 9, 2017
Chm 363 Spring 2017, Exercise Set 3 Transition Metal Bonding and Spectra Mr. Linck Version 1.5 March 9, 2017 3.1 Transition Metal Bonding in Octahedral Compounds How do the metal 3d, 4s, and 4p orbitals
More informationChapter 21. d-block metal chemistry: coordination complexes
Inorganic Chemistry B Chapter 21 d-block metal chemistry: coordination complexes Dr. Said El-Kurdi 1 21.1 Introduction In this chapter, we discuss complexes of the d-block metals and we consider bonding
More information11-1 Absorption of Light Quantum Numbers of Multielectron Atoms Electronic Spectra of Coordination Compounds
Chapter 11 Coordination Chemistry III: Electronic Spectra 11-1 Absorption of Light 11-2 Quantum Numbers of Multielectron Atoms 11-3 Electronic Spectra of Coordination Compounds Chapter 11 Coordination
More informationInorganic Chemistry with Doc M. Fall Semester, 2011 Day 19. Transition Metals Complexes IV: Spectroscopy
Inorganic Chemistry with Doc M. Fall Semester, 011 Day 19. Transition Metals Complexes IV: Spectroscopy Name(s): lement: Topics: 1. The visible spectrum and the d-orbitals 3. Octahedral fields. Term symbols
More informationElectronic structure Crystal-field theory Ligand-field theory. Electronic-spectra electronic spectra of atoms
Chapter 19 d-metal complexes: electronic structure and spectra Electronic structure 19.1 Crystal-field theory 19.2 Ligand-field theory Electronic-spectra 19.3 electronic spectra of atoms 19.4 electronic
More informationElectronic Selection Rules (II)
Term Symbols Electronic Selection Rules (II) IMPORTANT now we are finally ready to clearly define our electronic states! microstates for a particular atomic configuration are grouped into what are called
More informationCHEMISTRY. Electronic Spectra and Magnetic Properties of Transition Metal Complexes)
Subject Chemistry Paper No and Title Module No and Title Module Tag Paper 7: Inorganic Chemistry-II (Metal-Ligand Bonding, Electronic Spectra and Magnetic Properties of Transition Metal Complexes) 16.
More informationBonding in Coordination Compounds. Crystal Field Theory. Bonding in Transition Metal Complexes
Bonding in Transition Metal Complexes 1) Crystal Field Theory (ligand field theory) Crystal Field Theory Treat igands as negative charges (they repel the e- in the d orbitals deals only with d orbitals
More informationChemistry 1B. Fall Lectures Coordination Chemistry
Chemistry 1B Fall 2013 Lectures 13-14 Coordination Chemistry 1 LISTEN UP!!! WE WILL ONLY COVER LIMITED PARTS OF CHAPTER 19 (940-944;952-954;963-970) 2 good reasons for studying coordination chemistry a
More informationOrbitals and energetics
Orbitals and energetics Bonding and structure Molecular orbital theory Crystal field theory Ligand field theory Provide fundamental understanding of chemistry dictating radionuclide complexes Structure
More informationChapter 25 Transition Metals and Coordination Compounds Part 2
Chapter 25 Transition Metals and Coordination Compounds Part 2 Bonding in Coordination Compounds Valence Bond Theory Coordinate covalent bond is between: completely filled atomic orbital and an empty atomic
More informationChemistry Instrumental Analysis Lecture 11. Chem 4631
Chemistry 4631 Instrumental Analysis Lecture 11 Molar Absorptivities Range 0 to 10 5 Magnitude of e depends on capture cross section of the species and probability of the energy-absorbing transition. e
More informationInorganic Chemistry with Doc M. Day 19. Transition Metals Complexes IV: Spectroscopy
Inorganic Chemistry with Doc M. Day 19. Transition Metals Complexes IV: Spectroscopy Topics: 1. The visible spectrum and the d-orbitals 3. Octahedral fields 2. Term symbols and the method of microstates
More informationChemistry 324 Final Examination
Chem 324 Final Examination 2008 December 11, 2008 Page 1 of 8 Chemistry 324 Final Examination Thursday, December 11, 2008 Instructor: Dave Berg Answer all questions in the booklet provided; additional
More informationAbsorption Spectra. ! Ti(H 2 O) 6 3+ appears purple (red + blue) because it absorbs green light at ~500 nm = ~20,000 cm 1.
Absorption Spectra! Colors of transition metal complexes result from absorption of a small portion of the visible spectrum with transmission of the unabsorbed frequencies. Visible Spectra of [M(H 2 O)
More informationTransition Metals. Tuesday 09/22/15. Tuesday, September 22, 15
Transition Metals Tuesday 09/22/15 Agenda Topic 13.2 - Colored Complexes Topic 13.1 - First Row Transition Elements handout (this will be classwork for Wednesday & Thursday) The Periodic Table - The Transition
More informationChapter 21 d-block metal chemistry: coordination complexes
Chapter 21 d-block metal chemistry: coordination complexes Bonding: valence bond, crystal field theory, MO Spectrochemical series Crystal field stabilization energy (CFSE) Electronic Spectra Magnetic Properties
More informationInorganic Chemistry with Doc M. Day 18. Transition Metals Complexes IV: Ligand Field Theory continued
Inorganic Chemistry with Doc M. Day 18. Transition Metals Complexes IV: Ligand Field Theory continued Topics: 1. The three scenarios 2. Scenario 3: π-back bonding 1. The three scenarios for the MO energy
More informationChemistry 1B. Fall Lectures Coordination Chemistry
Chemistry 1B Fall 2012 Lectures 13-14 Coordination Chemistry 1 LISTEN UP!!! WE WILL ONLY COVER LIMITED PARTS OF CHAPTER 19 (pp. 933-937; 946-948; 958-966) [940-944;952-954;963-970] 7th 2 good reasons for
More informationindicating the configuration they correspond to and predict their relative energy.
Problem 1 (1 point) Three center four electron (3c/4e) bonds were introduced in class. John F. Berry (Dalton Trans. 2012, 41, 700-713) discusses the effect of the larger density of states for the 3c/4e
More informationChemistry 1B. Fall Topics Lectures Coordination Chemistry
Chemistry 1B Fall 2016 Topics Lectures 17-18 Coordination Chemistry 1 LISTEN UP!!! WE WILL ONLY COVER LIMITED PARTS OF CHAPTER 19 (940-944;952-954;963-970) 2 good reasons for studying coordination chemistry
More information18-Jul-12 Chemsheets A
www.chemsheets.co.uk 18-Jul-12 Chemsheets A2 038 1 SECTIN 1 - INTRDUCTIN 1) ELECTRN STRUCTURE & DEFINITIN F TRANSITIN METALS 2s 3s 1s 2p 3p 1s 4s fills before 3d. 4s also empties before 3d. 4s 3d Give
More informationTopics Coordination Complexes Chemistry 1B-AL, Fall 2016
Chemistry 1B Fall 2016 Topics Lectures 17-18 Coordination Chemistry 1 LISTEN UP!!! WE WILL ONLY COVER LIMITED PARTS OF CHAPTER 19 (940-944;952-954;963-970) 2 Page 1 good reasons for studying coordination
More informationCoordination and Special Materials Chemistry. Elective I/II: WS 2005/6 (Lecture) H.J. Deiseroth. Part 2
Coordination and Special Materials Chemistry Elective I/II: WS 2005/6 (Lecture) H.J. Deiseroth Part 2 Coordination Chemistry: Spectroscopy -microstates and spectroscopic symbols (RS and jj coupling), see
More informationA molecule s color can depend on oxidation state or liganded state. Example: oscillating clock. Consider the overall reaction: -
30.1.111 Lecture Summary #30 Transition Metals Topic: Crystal Field Theory and the Spectrochemical Series. Chapter 16 A molecule s color can depend on oxidation state or liganded state. Example: oscillating
More informationCrystal Field Theory History
Crystal Field Theory History 1929 Hans Bethe - Crystal Field Theory (CFT) Developed to interpret color, spectra, magnetism in crystals 1932 J. H. Van Vleck - CFT of Transition Metal Complexes Champions
More informationCHAPTER-7 CHARGE TRANSFER SPECTRA. Charge Transfer Spectra. Types of Charge Transfer Spectra
14 CHAPTER-7 CHARGE TRANSFER SPECTRA Charge Transfer Spectra An electronic transition between orbitals that are centred on different atoms is called charge transfer transition and absorption band is usually
More informationChapter 21: Transition Metals and Coordination Chemistry
Chapter 21: Transition Metals and Coordination Chemistry Mg, Cr, V, Co Pt Fe complexes O2 Mo and Fe complexes: nitrogen fixation Zn: 150 Cu, Fe: Co: B12 21.1 Transition Metals show great similarities within
More informationIf you put an electron into the t 2g, like that for Ti 3+, then you stabilize the barycenter of the d orbitals by 0.4 D o.
Crystal Field Stabilization Energy Week 2-1 Octahedral Symmetry (O h ) If you put an electron into the t 2g, like that for Ti 3+, then you stabilize the barycenter of the d orbitals by 0.4 D o. Each additional
More information4) Give the total number of electron domains and the hybridization for Xe in XeF 4. a) 6, sp 3 d 2 b) 4, sp 2 c) 5, sp 3 d d) 6, sp 3 e) 4, sp 3
1) The hybridization that allows the formation of 2 π bonds from unhybridized p-orbitals is a) sp b) sp 2 c) sp 3 d) sp 3 d e) sp 3 d 2 2) Electrons in bonds may become delocalized between more than two
More informationCoordination Chemistry: Bonding Theories. Crystal Field Theory. Chapter 20
Coordination Chemistry: Bonding Theories Crystal Field Theory Chapter 0 Review of the Previous Lecture 1. We discussed different types of isomerism in coordination chemistry Structural or constitutional
More informationChemistry 1000 Lecture 26: Crystal field theory
Chemistry 1000 Lecture 26: Crystal field theory Marc R. Roussel November 6, 18 Marc R. Roussel Crystal field theory November 6, 18 1 / 18 Crystal field theory The d orbitals z 24 z 16 10 12 8 0 0 10 10
More informationChapter 20 d-metal complexes: electronic structures and properties
CHEM 511 Chapter 20 page 1 of 21 Chapter 20 d-metal complexes: electronic structures and properties Recall the shape of the d-orbitals... Electronic structure Crystal Field Theory: an electrostatic approach
More informationChapter 19: d-metal Complexes: Electronic Structure and Spectra 121
Chapter 19: d-metal Complexes: Electronic Structure and Spectra 121 S19.9 Assign the bands in the spectrum of [Cr(NCS)613-? This six-coordinate d 3 complex undoubtedly has Oh symmetry, so the general features
More informationCO-ORDINATION COMPOUNDS
Unit - 9 CO-ORDINATION COMPOUNDS QUESTIONS VSA QUESTIONS (1 - MARK QUESTIONS) 1. Define the term coordination compound? 2. Write the names of counter ions in (i) Hg [Co (SCN and (ii) [Pt(NH 3. 3. Write
More informationCrystal Field Theory
Crystal Field Theory It is not a bonding theory Method of explaining some physical properties that occur in transition metal complexes. Involves a simple electrostatic argument which can yield reasonable
More informationMolecular Orbital Theory and Charge Transfer Excitations
Molecular Orbital Theory and Charge Transfer Excitations Chemistry 123 Spring 2008 Dr. Woodward Molecular Orbital Diagram H 2 Antibonding Molecular Orbital (Orbitals interfere destructively) H 1s Orbital
More informationCoordination Chemistry II: Bonding
d x2-y2 b 1g e g d x2-y2 b 1g D 1 t 2 d xy, d yz, d zx D t d d z2, d x2-y2 D o d z2 a 1g d xy D 2 d z2 b 2g a 1g e d z2, d x2-y2 d xy, d yz, d zx d xy b 2g D 3 t 2g e g d yz, d zx e g d yz, d zx 10 Coordination
More informationChem 1102 Semester 2, 2011!
Chem 110 Semester, 011! How is the ligand bonded to the metal? In octahedral complexes, six d sp 3 hybrid orbitals are used by the metal. The metal-ligand bond is a two-electron covalent bond. Mix d z,
More informationTransition Metal Chemistry
APPLIED INORGANIC CHEMISTRY FOR CHEMICAL ENGINEERS Transition Metal Chemistry CHEM261HC/SS1/01 Periodic table Elements are divided into four categories Main-group elements Transition metals 1. Main-group
More informationNAME: SECOND EXAMINATION
1 Chemistry 64 Winter 1994 NAME: SECOND EXAMINATION THIS EXAMINATION IS WORTH 100 POINTS AND CONTAINS 4 (FOUR) QUESTIONS THEY ARE NOT EQUALLY WEIGHTED! YOU SHOULD ATTEMPT ALL QUESTIONS AND ALLOCATE YOUR
More informationπ donor L L L π acceptor has empty π orbitals on ligand in to which d e- from M can be donated
Name KEY D# Chemistry 350 Fall 2005 Exam #4, November 18, 2005 50 minutes CCM 100 points on 4 pages + a useful page 5 1. Consider the molecular orbital diagram shown for M N. (16 pts) a) Indicate the following:
More informationChapter 20 d-block metal chemistry: coordination complexes
Chapter 20 d-block metal chemistry: coordination complexes Bonding: valence bond, crystal field theory, MO Spectrochemical series Crystal field stabilization energy (CFSE) Electronic Spectra Magnetic Properties
More informationExcited States in Organic Light-Emitting Diodes
Excited States in Organic Light-Emitting Diodes The metal-to-ligand charge transfer (MLCT) excited states of d 6 π coordination compounds have emerged as the most efficient for solar harvesting and sensitization
More informationElectronic Spectroscopy of Transition Metal Ions (continued)
Electronic Spectroscopy of Transition Metal Ions (continued) What about the spectroscopy! First some selection rules are found to apply: 1) Spin selection rule: S = 0 theory: transitions can only occur
More informationCHEM N-3 November Transition metals are often found in coordination complexes such as [NiCl 4 ] 2. What is a complex?
CHEM100 014-N-3 November 014 Transition s are often found in coordination complexes such as [NiCl 4 ]. What is a complex? 8 A complex contains a cation surrounded by ligands which bond to the cation using
More informationA Rigorous Introduction to Molecular Orbital Theory and its Applications in Chemistry. Zachary Chin, Alex Li, Alex Liu
A Rigorous Introduction to Molecular Orbital Theory and its Applications in Chemistry Zachary Chin, Alex Li, Alex Liu Quantum Mechanics Atomic Orbitals and Early Bonding Theory Quantum Numbers n: principal
More information- an approach to bonding that is useful for making estimates of E of orbitals in coordination complexes
10.4 Angular Overlap - an approach to bonding that is useful for making estimates of E of orbitals in coordination complexes - estimate the strength of interaction b/w ligand orbitals & metal d orbitals
More informationMolecular Orbital Theory (MOT)
Molecular Orbital Theory (MOT) In this section, There are another approach to the bonding in metal complexes: the use of molecular orbital theory (MOT). In contrast to crystal field theory, the molecular
More informationCHEM 116-Dr. Babb s Sections Answer Key to Lecture Problem Sheet Questions for Chapters 20, 21, and 23.
CHEM 116-Dr. Babb s Sections Answer Key to Lecture Problem Sheet Questions for Chapters 20, 21, and 23. 199. First complex: Co(NH 3 ) 6 Cl 3 + 3 AgNO 3 > Co(NH 3 ) 6 +3 + 3 AgCl(s); the three Cl - are
More informationMolecular Orbital Theory and Charge Transfer Excitations
Molecular Orbital Theory and Charge Transfer Excitations Chemistry 123 Spring 2008 Dr. Woodward Molecular Orbital Diagram H 2 Antibonding Molecular Orbital (Orbitals interfere destructively) H 1s Orbital
More informationCoordination Compounds. Compounds containing Transition Metals
Coordination Compounds Compounds containing Transition Metals Coordination Compounds Transition Metals Sc 6 Cu 1st row Y 6 Ag 2nd row La 6 Au 3rd row Properties of metals Not as reactive as group 1 or
More informationQuiz 5 R = lit-atm/mol-k 1 (25) R = J/mol-K 2 (25) 3 (25) c = X 10 8 m/s 4 (25)
ADVANCED INORGANIC CHEMISTRY QUIZ 5 and FINAL December 18, 2012 INSTRUCTIONS: PRINT YOUR NAME > NAME. QUIZ 5 : Work 4 of 1-5 (The lowest problem will be dropped) FINAL: #6 (10 points ) Work 6 of 7 to 14
More informationUltraviolet-Visible Spectroscopy
Ultraviolet-Visible Spectroscopy Introduction to UV-Visible Absorption spectroscopy from 160 nm to 780 nm Measurement of transmittance Conversion to absorbance * A=-logT=εbc Measurement of transmittance
More informationCrystal Field Theory
6/4/011 Crystal Field Theory It is not a bonding theory Method of explaining some physical properties that occur in transition metal complexes. Involves a simple electrostatic argument which can yield
More informationTransition Metal Chemistry
APPLIED INORGANIC CHEMISTRY FOR CHEMICAL ENGINEERS Transition Metal Chemistry CHEM261HC/SS1/01 Periodic table Elements are divided into four categories 1.Main-group elements 2.Transition metals 3.Lanthanides
More informationInorganic Chemistry with Doc M. Fall Semester, 2012 Day 21. Transition Metals Complexes V: Reaction Mechanisms
Inorganic Chemistry with Doc M. Fall Semester, 2012 Day 21. Transition Metals Complexes V: Reaction Mechanisms Name(s): Element: Topics: 1. Substitution reactions: dissociative v. associative 4. Pseudorotation
More informationPolar bonds, polar molecules and the shape of molecules.
Chapter 3 Polar bonds, polar molecules and the shape of molecules. Polar and non-polar bonds In homonuclear diatomic molecules such as H 2 or Cl 2 electrons are shared equally between equal atoms. The
More information1. [7 points] Which element is oxidized in the reaction below? + O 2 + H 2 O
1. [7 points] Which element is oxidized in the reaction below? K 2 CrO 4 (aq) + BaCl 2 (aq) BaCrO 4 (s) + 2KCl a. Cl b. Cr c. O d. Ba e. This is not an oxidation-reduction reaction 2. [7 points] What are
More informationThe d-block elements. Transition metal chemistry is d-orbitals/electrons
The d-block elements d-block elements include Sc-Zn, Y-Cd, a(or u)-hg. Transition metal chemistry is d-orbitals/electrons H&S, Fig 1.1, p. 15 Properties of transition metal ions are very sensitive to the
More informationPAPER No. 7: Inorganic chemistry II MODULE No. 5: Molecular Orbital Theory
Subject Chemistry Paper No and Title Module No and Title Module Tag 7, Inorganic chemistry II 5, Molecular Orbital Theory CHE_P7_M5 TABLE OF CONTENTS 1. Learning Outcomes 2. Introduction to Ligand Field
More informationChapter 24. Transition Metals and Coordination Compounds. Lecture Presentation. Sherril Soman Grand Valley State University
Lecture Presentation Chapter 24 Transition Metals and Coordination Compounds Sherril Soman Grand Valley State University Gemstones The colors of rubies and emeralds are both due to the presence of Cr 3+
More informationColors of Co(III) solutions. Electronic-Vibrational Coupling. Vibronic Coupling
Colors of Co(III) solutions Electronic-Vibrational Coupling Vibronic Coupling Because they have g g character, the d-d transitions of complees of the transition metals are forbidden (LaPorte forbidden).
More informationLecture 6: Physical Methods II. UV Vis (electronic spectroscopy) Electron Spin Resonance Mossbauer Spectroscopy
Lecture 6: Physical Methods II UV Vis (electronic spectroscopy) Electron Spin Resonance Mossbauer Spectroscopy Physical Methods used in bioinorganic chemistry X ray crystallography X ray absorption (XAS)
More informationvoltmeter salt bridge
2012 H2 Chemistry Preliminary Examination Paper 3 Solutions 1 1 (a) (i) 4FeCr 2 O 4 + 8Na 2 CO 3 + 7O 2 2Fe 2 O 3 + 8Na 2 CrO 4 + 8CO 2 a = 8, b = 7, c = 2, d = 8, e = 8 Any dilute acid e.g. dilute H 2
More informationSome chemistry of the Periodic Table. Electronic configuration and oxidation states of the transition metals
Some chemistry of the Periodic Table Electronic configuration and oxidation states of the transition metals Electronic configuration The d-block transition metals are defined as metals with an incomplete
More informationLecture 11 Reaction Types and Mechanisms for Inorganic Complexes
2P32 Principles of Inorganic Chemistry Dr. M. Pilkington Lecture 11 Reaction Types and Mechanisms for Inorganic Complexes Variations in reactivity Reaction types substitution, dissociation, addition and
More informationPeriodicity HL (answers) IB CHEMISTRY HL
Periodicity HL (answers) IB CHEMISTRY HL 13.1 First row d-block elements Understandings: Transition elements have variable oxidation states, form complex ions with ligands, have coloured compounds, and
More information401 Unit 3 Exam Spring 2018 (Buffers, Titrations, Ksp, & Transition Metals)
Seat# : 401 Unit 3 Exam Spring 2018 (Buffers, Titrations, Ksp, & Transition Metals) Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. (3 pts each)
More informationElectronic structure / bonding in d-block complexes
LN05-1 Electronic structure / bonding in d-block complexes Many, many properties of transition metal complexes (coordination number, structure, colour, magnetism, reactivity) are very sensitive to the
More informationChm December 2008
Inorganic Exam 3 Chm 451 4 December 2008 Name: Instructions. Always show your work where required for full credit. 1. (15 pts) True/False a T F Ionization energy decreases as one moves down from Li to
More informationCHEM Core Chemistry 3. Inorganic Reaction Mechanisms
CHEM3012 - Core Chemistry 3 Inorganic Reaction Mechanisms 5. Mechanisms of electron transfer between metal ions This section of the course is concerned with the mechanisms of electron transfer reactions,
More informationCrystal Field Theory. 2. Show the interaction between the d-orbital and the negative point charge ligands
1. What is the crystal field model? Crystal Field Theory It is a model that views complex ions as being held together ionically (this is not actually the case, but it allows for a simplification of the
More informationMn(acetylacetonate) 3. Synthesis & Characterization
Mn(acetylacetonate) 3 Synthesis & Characterization The acac Ligand Acetylacetonate (acac) is a bidentate anionic ligand ( 1 charge). We start with acetylacetone (or Hacac) which has the IUPAC name 2,4
More informationFACULTY OF SCIENCE AND FACULTY OF ETERNAL STUDIES BACHELOR OF EDUCATION (BED SCI) SCH 304: INORGANIC CHEMISTRY 4 CO-ORDINATION CHEMISTRY.
FACULTY OF SCIENCE AND FACULTY OF ETERNAL STUDIES BACHELOR OF EDUCATION (BED SCI) SCH 304: INORGANIC CHEMISTRY 4 CO-ORDINATION CHEMISTRY Written by Dr Lydia W. Njenga Department of chemistry Reviewed by
More informationTransition Metal Chemistry
APPLIED INORGANIC CHEMISTRY FOR CHEMICAL ENGINEERS Transition Metal Chemistry CHEM261HC/SS1/01 Periodic Table Elements are divided into four categories Main-group elements (S-Block) Transition metals 1.
More information5.04 Principles of Inorganic Chemistry II
MIT OpenCourseWare http://ocw.mit.edu 5.04 Principles of Inorganic Chemistry II Fall 008 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms. 5.04, Principles
More informationPAPER No.7 : Inorganic Chemistry-II MODULE No.1 : Crystal Field Theory
Subject Chemistry Paper No and Title Module No and Title Module Tag 7, Inorganic Chemistry II 1, Crystal Field Theory CHE_P7_M1 TABLE OF CONTENTS 1. Learning Outcomes 2. Introduction to Crystal Field Theory
More informationCoordination Chemistry: Bonding Theories. Molecular Orbital Theory. Chapter 20
Coordination Chemistry: Bonding Theories Molecular Orbital Theory Chapter 20 Review of the Previous Lecture 1. Discussed magnetism in coordination chemistry and the different classification of compounds
More informationAdvanced Analytical Chemistry
84.514 Advanced Analytical Chemistry Part III Molecular Spectroscopy (continued) Website http://faculty.uml.edu/david_ryan/84.514 http://www.cem.msu.edu/~reusch/virtualtext/ Spectrpy/UV-Vis/spectrum.htm
More informationChemical bonding in complexes of transition metals
Chemical bonding in complexes of transition metals Chem 202, Sept. 28, 2010 What are transition elements? Electronic structure of atoms Naming delocalized molecular orbitals: tetrahedral and octahedral
More informationTopics Coordination Complexes Chemistry 1B-AL, Fall 2016
Chemistry 1B Fall 2016 LISTEN UP!!! Topics Lectures 17-18 Coordination Chemistry WE WILL ONLY COVER LIMITED PARTS OF CAPTER 19 (940-944;952-954;963-970) 1 2 good reasons for studying coordination chemistry
More informationCoordination chemistry and organometallics
Coordination chemistry and organometallics Double salt and Complex salt A salt that keeps its identity only in solid state is called a double salt. In solution they dissociate into component ions. E.g.:
More informationM1. (a) Yellow (solution) 1. Orange solution 1 SO 4. Yellow / purple (solution) Allow orange / brown (solution) 1. Brown precipitate / solid 1 + 3H 2
M. (a) Yellow (solution) range solution Cr + H + Cr 7 + H Allow equation with H S (b) Yellow / purple (solution) Allow orange / brown (solution) Brown precipitate / solid [Fe(H ) 6 ] + + H Fe(H ) (H) +
More informationTransition Metal Elements and Their Coordination Compounds
Fernando O. Raineri Office Hours: MWF 9:30-10:30 AM Room 519 Tue. 3:00-5:00 CLC (lobby). Transition Metal Elements and Their Coordination Compounds 2 Compounds. Naming and Geometry. 1 3 p.1046a 4 Fig.
More informationElectronic Spectroscopy of Polyatomics
Electronic Spectroscopy of Polyatomics We shall discuss the electronic spectroscopy of the following types of polyatomic molecules: 1. general AH 2 molecules, A = first-row element 2. formaldehyde 3. benzene
More informationCr(II) or Cr 2+ Consider the octahedral complex Cr[(en) 3 ] 2+ Octahedral complex with 4 d electrons. Octahedral complex with 4 d electrons
Cr [Ar] 4s 1 3d 5 Cr 2+ [Ar] 3d 4 Consider the octahedral complex Cr[(en) 3 ] 2+ Cr(II) or Cr 2+ Pairing energy Octahedral complex with 4 d electrons Octahedral complex with 4 d electrons Δ is large Δ
More informationTopic 9.4: Transition Elements Chemistry
Topic 9.4: Transition Elements Chemistry AJC 2009/P3/Q3c,d 1 167 CJC 2009/P2/Q3a-c 2 (a) Cr: 1s 2 2s 2 2p 6 3s 2 3p 6 3d 5 4s 1 or [Ar] 3d 5 4s 1 Cr 3+ : 1s 2 2s 2 2p 6 3s 2 3p 6 3d 3 or [Ar] 3d 3 (b)
More informationBonding in Transition Metal Compounds Oxidation States and Bonding
Bonding in Transition Metal ompounds Oxidation States and Bonding! Transition metals tend to have configurations (n 1)d x ns 2 or (n 1)d x ns 1, Pd having 4d 10 5s 0. K All lose ns electrons first, before
More information