Complex ions Flashcards
Example of a complex ion, and how does it work
Anti cancer drug - cis-platin PtCl2(NH3)2
cisplatin bonds to the DNA of cancer cells and stops them replicating
What is a coordinate bond?
a dative covalent bond in which one atom donates the shared pair of electrons
What is a complex ion?
formed when ligands coordinate (datively covalent) bond to a central metal ion
What is a coordination number?
number of coordination bonds to the central metal ion in a complex ion
What is a ligand?
a molecule or ion with a lone pair which it donates to a metal ion to form a coordinate bond
What is a monodentate ligand?
a molecule or ion with 1 lone pair which it donates to a metal ion to form 1 coordinate bond
What is a bidentate ligand?
a molecule or ion with 2 lone pair which it donates to a metal ion to form 2 coordinate bond
What is a hexadentate ligand?
a molecule or ion with 6 lone pair which it donates to a metal ion to form 6 coordinate bond
Give some examples of monodentate ligands?
H2O, NH3, I-, F-, Br-, Cl-, -:C=-N: (cyanide), :C=-O:, -:S-C=-N:
Give some examples of bidentate ligands?
ethanediamine (NH2CH2CH2NH2) (neutral)
2,2-bipyridine
ethanedioate (-:OCOCOO:-) (charged)
What are the three main types of complex ions?
[CU(H2O)6]2+ - 6 co-ordinate, octahedral, 90 bond angle, 2+, water - small ligand
[CuCl4]-2 - 4 co-ordinate, tetrahedral, 109.5 bond angle, chloride - larger ligand
[PtCl4]-2 - 4 co-ordinate, square planar, 90 bond angle, chloride - larger ligand
What is the Ligand exchange reaction for CuSO4? (TM ion present, complex ion, ppt formed)
TM ion - Cu+2
Complex ion - [Cu(H2O)6]+2
ppt formed - [Cu(OH)2(H2O)4] blue
What is the Ligand exchange reaction for FeSO4? (TM ion present, complex ion, ppt formed)
TM ion - Fe+2
Complex ion - [Fe(H2O)6]+2
ppt formed - [Fe(OH)2(H2O)4] pale green, oxidises to brown
What is the Ligand exchange reaction for FeCl3? (TM ion present, complex ion, ppt formed)
TM ion - Fe+3
Complex ion - [Fe(H2O)6]+2
ppt formed - [Fe(OH)3(H2O)3] orange/brown
What is the Ligand exchange reaction for MnSO4? (TM ion present, complex ion, ppt formed)
TM ion - Mn+2
Complex ion - [Mn(H2O)6]+2
ppt formed - [Mn(OH)2(H2O)4] light brown
What is the Ligand exchange reaction for Cr2(SO4)3? (TM ion present, complex ion, ppt formed)
TM ion - Cr+3
Complex ion - [Cr(H2O)6]+3
ppt formed - [Cr(OH)3(H2O)3] green, disappears because all water is kicked out
What are the observations of CUSO4 with excess NH3?
dark blue solution
[Cu(H2O)6]+2 + 4NH3 –> [Cu(NH3)4(H2O)2]+2 + 4H2O
What are the observations of Cr2(SO4)3 with excess NH3?
violet solution
[Cr(H2O)6]+3 + 6NH3 –> [Cr(NH3)6]+3 + 6H2O
What is the reaction for [Cu(H2O)6]+2 + 4Cl- ?
[Cu(H2O)6]+2 + 4Cl- –> [CuCl4]-2 + 6H2O
How are haemoglobin Fe+2 complex ions used?
between O2 and CO2
Fe+2N4globinO=O + CO2 <—> Fe+2N4globinO=C=O
carbon monoxide poisoning is irreversible ligand exchange between the CO and O2
How does Fe+2 turn to Fe+3 and vice versa
Fe+2 –> Fe+3 - oxidise, KMnO4- (oxidising agent)
Fe+3 –> Fe+2 - reduce I- –> -2 (reducing agent)
What is the reaction for blue copper (II) sulfate + KI?
Blue –> brown, White ppt
I- + 2Cu+2 –> I2 + 2CuI
What is the reaction for orange potassium dichromate + H2SO4 + KI?
orange –> brown
Cr2O7-2 + 14H+ +6I- –> 2Cr+3 + 7H2O + 3I2
What is the reaction for green chromium (III) sulfate + NaOH + H2O2?
green –>
3H2O2 + 2Cr+2 + 10OH- –> 2CrO4-2 + 8H2O
What is the reaction of H2SO4 + red copper (I) oxide?
colourless + red –> blue + brown
Cu2O +H2SO4 –> CuSO4 + Cu + H2O
