Transition Metal Chemistry and Coordination Compounds Chapter 20 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

20.1 The Transition Metals

20.1

Oxidation States of the 1 st Row Transition Metals (most stable oxidation numbers are shown in red) 20.1

Ionization Energies for the 1 st Row Transition Metals

ScandiumTitaniumVanadium ChromiumManganeseIron CobaltNickelCopper 20.2

________________ Compounds A ________________ ________________ typically consists of a complex ion and a counter ion. A _______________ ________ contains a central metal cation bonded to one or more molecules or ions. The molecules or ions that surround the metal in a complex ion are called ligands. A _________ has at least one unshared pair of valence electrons H O H H N H H Cl - C O 20.3

Coordination Compounds 20.3 The atom in a ligand that is bound directly to the metal atom is the donor atom. H O H H N H H The number of donor atoms surrounding the central metal atom in a complex ion is the _______________ _______________. Ligands with: one donor atom _____________ two donor atoms __________ three or more donor atoms _____________ H 2 O, NH 3, Cl - ethylenediamine EDTA

Coordination Compounds 20.3 H 2 N CH 2 CH 2 NH 2 bidentate ligand polydentate ligand (EDTA) Bidentate & polydentate ligands are called ________________

20.3

EDTA Complex of Lead 20.3

What are the oxidation numbers of the metals in K[Au(OH) 4 ] and [Cr(NH 3 ) 6 ](NO 3 ) 3 ? OH - has charge of ___ K + has charge of _____ ? Au x(-1) = 0 Au = _____ NO 3 - has charge of ___ NH 3 has no charge ? Cr + 6x(0) + 3x(-1) = 0 Cr = ___ 20.3

Naming Coordination Compounds 20.3 The cation is named before the anion. Within a complex ion, the ligands are named first in alphabetical order and the metal atom is named last. The names of anionic ligands end with the letter o. Neutral ligands are usually called by the name of the molecule. The exceptions are H 2 O (aquo), CO (carbonyl), and NH 3 (ammine). When several ligands of a particular kind are present, the Greek prefixes di-, tri-, tetra-, penta-, and hexa- are used to indicate the number. If the ligand contains a Greek prefix, use the prefixes bis, tris, and tetrakis to indicate the number. The oxidation number of the metal is written in Roman numerals following the name of the metal. If the complex is an anion, its name ends in –ate.

20.3

What is the systematic name of [Cr(H 2 O) 4 Cl 2 ]Cl ? ______________________________ Write the formula of tris(ethylenediamine)cobalt(II) sulfate ___________________

Structure of Coordination Compounds 20.4 Coordination numberStructure ______________________

Structure of Coordination Compounds 20.4 _________________ are compounds that are made up of the same types and numbers of atoms bonded together in the same sequence but with different spatial arrangements. _________________ isomers are stereoisomers that cannot be interconverted without breaking a ___________________. cis-[Pt(NH 3 ) 2 Cl 2 ] trans-[Pt(NH 3 ) 2 Cl 2 ]

Structure of Coordination Compounds 20.4 cis-[Co(NH 3 ) 4 Cl 2 ]trans-[Co(NH 3 ) 4 Cl 2 ] Are these additional geometric isomers of [Co(NH 3 ) 4 Cl 2 ]? cis trans

Structure of Coordination Compounds 20.4 __________ isomers are nonsuperimposable mirror images. cis-[Co(en) 2 Cl 2 ]trans-[Co(en) 2 Cl 2 ] optical isomers ________ not optical isomers __________

Structure of Coordination Compounds 20.4 Chiral molecules are ________________ active.

Bonding in Coordination Compounds 20.5 All equal in energy in the absence of __________!

Bonding in Coordination Compounds 20.5 Isolated transition metal atom Bonded transition metal atom ____________________ (  ) is the energy difference between two sets of d orbitals in a metal atom when ligands are present

Bonding in Coordination Compounds 20.5  E = h

The absorption maximum for the complex ion [Co(NH 3 ) 6 ] 3+ occurs at 470 nm. What is the color of the complex and what is the crystal field splitting in kJ/mol? Absorbs blue, will appear orange.  = h hc = (6.63 x J s) x (3.00 x 10 8 m s -1 ) 470 x m = = 4.23 x J  (kJ/mol) = 4.23 x J/atom x x atoms/mol = 255 kJ/mol 20.5

Bonding in Coordination Compounds 20.5 I - < Br - < Cl - < OH - < F - < H 2 O < NH 3 < en < CN - < CO Spectrochemical Series Strong field ligands Large  Weak field ligands Small 

Bonding in Coordination Compounds 20.5

Orbital Diagrams for High Spin and Low Spin Octahedral Complexes

Bonding in Coordination Compounds 20.5

Bonding in Coordination Compounds 20.5

Chemistry In Action: Coordination Compounds in Living Systems

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