Coordination Chem

Question 1

Complex

Answer 1

An electron acceptor surrounded in a symmetrical manner by a shell of ions or molecules called ligands, held together by dative bonds

Question 2

Chelate ligands

Answer 2

Subset of polydentate ligands, involving simultaneous binding of multiple donor atoms by forming rings around the central atom

Question 3

Bridging ligands

Answer 3

Attached to multiple metallic central ions

Question 4

Ambidentate ligands

Answer 4

Molecules that can vary which atom bonds to the central electron acceptor

Question 5

Coordination number

Answer 5

Number of ligand atoms directly bonded to central electron acceptor

Question 6

Isomerism

Answer 6

Same formula, different structure

Question 7

Geometric isomers

Answer 7

Different arrangement round central electron acceptor (e.g. cis and trans)

Question 8

Optical

Answer 8

Enantiomers: Non-superimposable mirror images, interact differently in chiral environments

Question 9

Coordination isomerism

Answer 9

Variation of ions in compounds made up of both ionic and cationic complex ions, no neutral species

Question 10

Hydrate isomerism

Answer 10

Possible when water is present

Question 11

Ionisation isomerism

Answer 11

Possible in compounds with complex ions and a counter ion, different distribution of ions between directly coordinated and counter ions

Question 12

Linkage isomerism

Answer 12

Possible when ambidentate ligands are present

Question 13

Ligand isomerism

Answer 13

Only organic ligands (e.g. 2-,3-,4-aminotoluene)

Question 14

Ligand Formulae order

Answer 14

Square brackets
Metal ion
Anionic ligands (alphabetical)
Neutral ligands (alphabetical)

Question 15

Ligand nomenclature order

Answer 15

Ligands listed alphabetically before metal, ignoring prefixes

Question 16

Anionic complex ending

Answer 16

“-ate”

Question 17

Prefixes

Answer 17

Mono
Di
Tri
Tetra
Penta
Hexa
Hepta
Octa

Question 18

Multiplicative prefixes

Answer 18

bis
tris
tetrakis
pentakis
hekakis

Question 19

Bridging ligands

Answer 19

Indicated by μ

Question 20

Overall stability constant β

Answer 20

Eqm constant for overall reaction, taking each water displacement step into consideration.
Large β means that ligand substitution reaction is favoured

Question 21

Statistical factor for β

Answer 21

Constants decrease if there is no change in geometry

Question 22

Steric factor for β

Answer 22

Bulky substituents can hinder the approach of subsequent ligands

Question 23

Electrostatic factor for β

Answer 23

Each successive replacement of water reduces +ve charge, causing repulsion

Question 24

Chelate effect for β

Answer 24

Chelate complexes more stable than similar monodentate complexes

Question 25

Macrocyclic effect

Answer 25

3 or more potential donors in a ring of at least 9. Stability constants for complexes of macrocyclic ligands are greater than acyclic equivalents

Question 26

Hard acid

Answer 26

Non-polarisable cations, small-radius, high effective nuclear charge, high energy LUMO

Question 27

Hard base

Answer 27

Small
Electronegative
Non-polarisable
Low energy HOMO