coordination

Question 1

Transition Metal:

Answer 1

An element with an unfilled d- or f-orbital (i.e. partially filled d- or f- sub-shell) in at least one common oxidation state

Question 2

Complex (or Coordination Compound)

Answer 2

Positively charged central ion (or possibly a neutral atom), an acceptor, surrounded in a symmetrical manner by a shell of ions or molecules called ligands.

Question 3

Acceptor

Answer 3

electrophile or Lewis acid (e– pair acceptor)

Question 4

Ligand

Answer 4

nucleophile or Lewis base (e– pair donor)

Question 5

A complex consists of

Answer 5

Question 6

Monodentate ligand and 5 neutral and anionic monodentate ligands

Answer 6

Question 7

Bidentate Ligands and 3 neutral and 1 anionic Bidentate ligands

Answer 7

Question 8

Bidentate ligands ring formation

Answer 8

Question 9

Tridentate ligands

Answer 9

Question 10

Tetradentate ligands

Answer 10

Question 11

Hexadentate Ligands

Answer 11

Question 12

Chelation

Answer 12

Question 13

Ethylenediaminetetraacetate, [EDTA]4-

Answer 13

Question 14

Ambidentate Ligands

Answer 14

A ligand that can coordinate via different atom within the ligand depending on the circumstances

Question 15

Bridging ligand

Answer 15

A ligand attached to two or more, usually metallic, central atoms.

Question 16

Coordination Number (‘CN’)

Answer 16

Number of ligand atoms directly bonded to central metal in the complex.

Note: Coordination Number IS NOT the number of ligands bonded to the metal so take care with multi-dentate ligands!

Question 17

CN geometry

Answer 17

Question 18

CN number depends on:

Answer 18

Question 19

Answer 19

Question 20

Stereoisomerism

Answer 20

Stereoisomerism (different arrangement of atoms in space)

– Geometric

– Optical

Question 21

Structural (or Constitutional) Isomerism

Answer 21

Structural (or Constitutional) Isomerism (different bonds between atoms)

• Coordination
• Hydrate
• Ionisation
• Linkage
• Ligand

Question 22

Coordination isomer

Answer 22

Question 23

Hydrate isomer

Answer 23

Question 24

Ionisation isomer

Answer 24

Question 25

Linkage isomer

Answer 25

Linkage isomerism requires ambidentate ligands to be present such as NCS- which can coordinate to a metal centre through either the nitrogen or sulphur atom.

Question 26

Ligand isomer

Answer 26

Question 27

Formulae

Answer 27

1. In square brackets []; cation then anion
2. Metal ion first
3. Anionic ligands next (alphabetic order)
4. Neutral ligands next (alphabetic order)
5. outside brackets

Question 28

Naming complexes

Answer 28

1. The name of the cation appears first; the anion is named last.
2. Ligands are listed alphabetically before the metal.
3. NB: Ignore prefixes when alphabetising.

Question 30

Geometric isomerism

Answer 30

Geometric isomerism is where there is a di”erent arrangement of atoms in space. For this example there is only one possible way to arrange the atoms around the metal centre.

Question 31

Optical isomerism

Answer 31

• Optical isomers are non-superimposable on their mirror images. There are too many ligands of one type (NH3) for this to be

possible.

Question 32

Nomenclature prefix

Answer 32

Question 33

Ligands nomenclature

Answer 33