Complex Ions

Complex Ion An ion formed when a positive central element binds with multiple ions or polar molecules

The central element is almost always a positively charged metal Complex Ion The central element is almost always a positively charged metal

Describe or define a Complex Ion

Negatively charged ion Anion Negatively charged ion

Positively charged ion Cation Positively charged ion

Metal Ion Examples Cu+2 Cu+ Au+ Ag+ Zn+2 Ni+2 Pt+2 Co+2 Al+3

Ligands The negative ions or polar molecules bound by the central element in a complex ion

Ligand Examples Cl- F- H2O NH3 CN- Br- NO O2 OH-

Ligands that can bind to more than one point Polydentate Ligands Ligands that can bind to more than one point

Ligands that can bind to two points in a complex ion Bidentate Ligands Ligands that can bind to two points in a complex ion

Bidentate Examples H2N-CH2-CH2-NH2 -O2C-CO2-

Ligands that can bind to three points in a complex ion Tridentate Ligands Ligands that can bind to three points in a complex ion

Tridentate Examples H2-C-COO- HO-C-COO-

Polydentate ligands that bind to metal ions in solution Chelates Polydentate ligands that bind to metal ions in solution

Coordination Number The number of points in which ligands bind to the central element in a complex ion

Coordinate Covalent Bond Covalent bonds in which both electrons involved are donated by one atom

The bonds formed in a complex ion are coordinate covalent bonds Complex Ions The bonds formed in a complex ion are coordinate covalent bonds

A complex ion and its counter ion Coordination Complex A complex ion and its counter ion

The bonds formed in a complex ion are coordinate covalent bonds Complex Ions The bonds formed in a complex ion are coordinate covalent bonds

Complex Ion Because of the type bonding, they are sometimes called coordinate complexes

1) Name cations before anions

2) Name ligands before metal in the complex ion Naming Complexes 2) Name ligands before metal in the complex ion

a) give neutral compds normal names except: 2) Naming Ligands a) give neutral compds normal names except:

H2O aqua NH3 amine CO carbonyl NO nitrosyl

b) change -ide endings to -o for all anions 2) Naming Ligands b) change -ide endings to -o for all anions

d) use geometric prefixes for monodentate ligands 2) Naming Ligands d) use geometric prefixes for monodentate ligands

e) use bis- for 2 & tris- for 3 polydentate ligands 2) Naming Ligands e) use bis- for 2 & tris- for 3 polydentate ligands

a) use the normal name if the complex ion is (+) 3) Naming Metal a) use the normal name if the complex ion is (+)

b) make the metal ending -ate if the complex ion is (-) 3) Naming Metal b) make the metal ending -ate if the complex ion is (-)

d) use Roman numerals in () to indicate metal ox # 3) Naming Metal d) use Roman numerals in () to indicate metal ox #

Name the Following: [Pt(NH3)4]Cl2 [Co(H2O)2Cl4]-2 [Cu(H2O)2(en)2]I2

Predict # of isomers of each: [Pt(NH3)4 Cl2] [Co(H2O)3Cl3]

Complex Ion Shapes 2-linear 4-tetrahedral or sq pl 6-octahedral

Square planar vs tetrahedral Geometric Isomers Square planar vs tetrahedral cis vs trans

Geometric Isomers Bunched octa- T-shaped octa- bis: cis vs trans

Optical Isomers Tri-bis mirror images

CN- > NO2- > en > NH3 > NCS- > H2O > F- > Cl- Field Strength CN- > NO2- > en > NH3 > NCS- > H2O > F- > Cl-

Field Strength CN- is strong field Cl- is weak field

Determines d-level splitting or Do(splitting energy) Field Strength Determines d-level splitting or Do(splitting energy)

Large Do yields low spin or diamagnetic compds Field Strength Large Do yields low spin or diamagnetic compds

Small Do yields high spin or paramagnetic compds Field Strength Small Do yields high spin or paramagnetic compds

Name, shape, & possible isomerism [Pt(NH3)2I4]-2 Determine: Name, shape, & possible isomerism

[Co(NH3)6]+3 yellow [Co(NH3)5NCS]+2 orange [Co(NH3)5H2O]+2 red [Co(NH3)5Cl]+2 purple t-[Co(NH3)4Cl2]+1 green

Complex Ion Equilibria Cu+2 + 4 NH3 [Cu(NH3)4]+2 [Cu(NH3)4]+2 [Cu+2][NH3]4 Kf =

Calculate the ratio of [Cu+2]/ [Cu(NH3)4]+2 when Cu+2 is added to a 0 Calculate the ratio of [Cu+2]/ [Cu(NH3)4]+2 when Cu+2 is added to a 0.10 M NH3 solution: Kf = 2.0 x 1012

The larger the Kf, the more likely the complex will form Common Ion Equilibria The larger the Kf, the more likely the complex will form

Common Ion Equilibria Kf for [Ag(NH3)2]+1 = 1.7 x 107 Kf for [Ag(CN)2]-1 = 2.0 x 1020

Common Ion Equilibria Kf for [M(NH3)2]+2 = 1.7 x 107 Kf for [M(CN)4]-2 = 2.0 x 1020

Common Ion Equilibria CN- will replace NH3 in the complex with silver

[Zn(NH3)2H2OF]+1 [Co(NH3)3ClFI]-1 Calculate: a) coordination # b) number of isomers c) oxidation # of metal [Zn(NH3)2H2OF]+1 [Co(NH3)3ClFI]-1