Chem 2c Midterm 1

Coordination compounds

transition metal ions, in combination with ligands and counterions

general term for neutral compounds containing transition metals

complex ions

transition metal ions in combination with ligands

used when transition metal species have a nonzero charge

counterions

anions or cations needed to produce a compound with no net charge

coordination number

the number of nearest neighbors to the transition metal ion

typically the number of ligand surrounding the ion

ligands

lewis base (electron pair donor)

will have a lone pair of electrons ready to form a bond

has negative or neutral cha

monodente

a ligand with one pair of electrons to bond

polydente

a ligand with two or more elctron pairs to bond with

monodente ligands (examples)

polydente ligands (examples)

ionization isomers

a structural isomer where a ligand and counter ion switch

coordination isomers

structural isomer where the transition metals of a bi-metallic species switch ligands

linkage isomers

structural isomers where a multi-atom ligand connects to the transition metal through different atoms

geometric isomers

a stereoisomer where the arrangement of ligands are either neighboring (cis or fac) or across (trans or mer) from each other

structural isomers

compounds that can have different connectivity

stereoisomers

compounds that can have different arrangement of atoms in space

cis/trans isomerism

occurs only in square planar and octahedral complexes

2 identical ligands are either neighboring (cis) or opposite (trans)

fac/mer isomerism

occurs only in octahedral complexes

3 identical ligands are either neighboring (fac) or across (mer)

optical isomer

subcategory of a stereoisomer where the arrangement of atoms results in a non superimposable mirror image

also called chiral or optically active

enantiomer

the set of mirror image optical isomers

Octahedral Crystal field theory diagram

Opposite of tetrahedral

Tetrahedral Crystal field theory diagram

Opposite of octahedral diagram

Square planar Crystal field theory diagram

Never fill top level unless all 10 e- are present

Linear Crystal field theory diagram

Crystal Field theory electron filling

Strong field:

• low-spin

• orbitals far apart (large Δ)

• bottom level fills first before moving to the next level

Weak field:

• high spin

• orbitals close together (small Δ)

• all orbitals fill singly first

How to determine Δ