complexes Flashcards
ligand def
Molecule/ion taht donates pair of electrons to central metal ion 2 form coord bond
coord bond def
shared pair of electrons between 2 atoms where both electrons come from same atom
coord number def
total n coord bonds formed between ligands & central metal ion
Cu2+(AQ) + Cl- (aq) products colours type of reaction
- [Cu(H2o)6]2+ + 4Cl- [CuCl4]2- + 6H2o
- above blue solution to yellow solution
what r ligand substiution reactions
- one type ligand in complex ion is replaced by another
- colour change ocurrs
wt happens if ligands r similar in size & give example
- H2o & nh3
- COORD NUMBER DOESNT CHANGE
wt happens if ligands r diff in size & give example
- H2o + Cl-
- coord n changes
[Cu(H2o)6]2+ (aq) x excess NH3 (aq)
- [Cu(H2o)6]2+ (aq) + 4NH3 (aq) ——> [Cu(NH3)4 (H2o)2]2+ (aq) + 4h2o
- PALE B;UE TO DEEP BLUE
[Cu(H2o)6]2+ (aq) x excess conc HCL (aq) & additional point
- [Cu(H2o)6]2+ (aq) + 4Cl- (aq) ⇌ [CuCl4]2- (aq) + 6H2o(l)
- pale blue to yellow
- test tube often appears green coz reversible reaction
[Cr(H2o)6]3+ (aq) + excess NH3 (aq)
- [Cr(H2o)6]3+ + 6NH3(aq) → [Cr(NH3)6]3+ (aq) + 6H2o(l)
- VIOLET to purple
how ligand sub & haemoglobin
- protein globin attaches from coord bond from N to fe 2+
- then haem group added so 5 coord bonds made by N atoms
- 6th coord bond made w o2 oxyhaemoglobin
what can bind to fe2+ in haem and whats it called & wt happens
- CO can bind w Fe2+
- (carboxyhemoglobin)
- thus ability of blood to carry o2 reduced
- if conc carboxyhaem gets too high can lead to death
wts a precipitate reaction
2 aqueous solutions containing ions react together forming insiluble ionic solid
what happens when AQ trans metals react w AQ NaOH
form trans metal hydroxide PRECIPITATES SAME FOR AQ AMMONIA
wt can some precipitates do in excess NaOH/ ecess NH3 to form
- dissolve in them to form
- aqueous complexes
Cu(H2o)6]2+ (aq) x OH-
- [Cu(H2o)6]2+ (aq) x 2OH- ——> Cu(OH)2(H2O)4 + 2h2o
- PRECIPITATE INSOLUBLE IN EXCESS NaOH
- blue sol blue precipitation
- or jus Cu2+ + 2OH- —> Cu(OH)2 (s)
[Cu(H2o)6]2+ (aq) x NH3
- [Cu(H2o)6]2+ (aq) + 2NH3(aq) ——> Cu(OH)2(H2O)4 + 2NH4+ (aq)
- blue sol blue precip
[Cu(H2o)6]2+ (aq) x NH3 excess ammonia
- the precipitate Cu(OH)2(H2O)4 undergoes
- ligand substitution
- [Cu(H2o)6]2+ (aq) + 4NH3(aq) ——> [Cu(NH3)4(H2O)2]2+ (aq) + 2H2O(l) + 2OH- (aq)
- blue to dark blue
[Fe(H2o)6]2+ (aq) x OH- (fe II) = 2+
- [Fe(H2o)6]2+ (aq) x 2OH- (aq) —→ [Fe(OH)2(H2O)4] s + 2H2o l
- green to green solid
- insoluble precipitate IN EXCESS NaOH
wt happens to Fe precipiatte when standing in air
- starts turning brown from green
- Oxidises
Fe(H2o)6]2+ (aq) x NH3 aq
- [Fe(H2o)6]2+ (aq) + 2NH3(aq) ——> Fe(OH)2(H2O)4 + 2NH4+ (aq)
- or Fe2+ aq + 2OH- aq —→ FE(OH)2 s
- Precipitate insouble in excess NH3
[Fe(H2o)6]3+ (aq) x OH- (fe III) = 3+
- [Fe(H2o)6]3+ (aq) x 3OH- (aq) —→ [Fe(OH)3(H2O)3] s + 3H2o
- yellow to orangey-brown
- fe3+ (aq) + 3OH- (aq) —→ Fe(OH)3 (s)
- insoluble in excess NaOH
[Fe(H2o)6]3+ (aq) x NH3 aq
- [Fe(H2o)6]3+ (aq) + 3NH3(aq) ——> Fe(OH)3(H2O)3 + 3NH4+ (aq)
- yellow to orangey brown
- insoluble precip in excess NH3
[Mn(H2o)6]2+ + OH-
- [Mn(H2o)6]2+ (aq) x 2OH- (aq) —→ [Mn(OH)2(H2O)4] s + 2H2o l
- pink to light brown solid precip
- mn2+ aq + 2oh- —> Mn(OH)2 (s)
- light brown starts 2 darker on standing in air
- insoluble precip in excess NH3
