Transition Metal Chemistry

Titanium Chemistry

-Second in abundance of transition metals-Excellent corrosion resistance-High heat transfer efficiency-Good strength to weight ratio-Extraction: TiO2 + C + 2Cl2 --> TiCl4 + CO2 (Kroll process) TiCl4 + 2Mg --> Ti + 2MgCl2 (purified by distillation (b.p. 136oC) -Titanium Halides, prepared by direct reaction of Ti with the halogen gas: TiF4 - white liquid TiCl4 - colourless liquid TiBr4 - yellow solid TiI4 - violet/black solid For TiX3 - reduction of TiX4 and H2

-Titanium oxides:--Prepared by hydrolysis of TiX4 or Ti(III) salts--TiO2 reacts with acids AND bases: TiOSO4 formed in H2SO4 MTiO3 (M = CaTiO3 - perovskite) - metatitanates M2TiO4 - orthotitanates Complexes, good Lewis acid - forms adducts on reaction with Lewis bases 2PEt3 + TiCl4 --> TiCl4(PEt3)2 2MeCN +TiCl4 -->TiCl4(MeCN)2 bipy + TiCl4 --> TiCl4(bipy) Solvolysis - if ionisable protons present in ligand 2NH3 + TiCl4 -->TiCl2(NH2)2 + 2HCl 4H2O +TiCl4 --> TiO2 +4HCl 2EtOH + TiCl4 --> TiCl2(OEt)2 + 2HCL

Vanadium Chemistry

-Plays a number of roles in biological systems-Amanita Muscaria (a mushroom) can accumulate vanadium in the form of amavadin-Can exist in a wide number of oxidation states but the key ones are: +2, +3, +4 and +5-+2 and +3 are reducing but +4 is stable, +5 is slightly oxidising-Vanadium Oxides:-VO, V2O3, V2O4, & V2O5--V2O5 - amphoteric and aq chem. v complex and pH  dependent--when dissolved in v. strong NaOH sol. a colourless solution containing VO43- (vanadate) formed.--When acid is added protons added and polymerisation occurs to produce diff.  oxy ions[VO4]3-(pH12) --> [VO3.OH)2-(pH10) --> [V2O6.OH]3-(PH9)    --> [V3O9]3-(pH7) --> [V5014]3-(pH6.5) --> V2O5(H20)n(pH2.2) --> [V10O28]6-(pH<1) [VO2]+ VANADYL

-Vanadium Halides:-+5: Only +5 complex is VF5 - white solid, based on trigonal bipyramid in gas phase. Solid state is a fused octahedral:-2V + 5F2 --> 2VF5 (300oC)-+4: Halides more common, prepared via numerous routes -VF4 VCl4 and VBr4 -VCl4 prepared by reacting with chlorinating  agents i.e-Cl2, SOCl2 or COCl2TERTRAHALIDES tend to be disproportionate-2VCl4 --> 2VCl3 + Cl2 (at room temp.) (can't get VCl5)-Halides hydrolyse in water- VCl4 + H2O --> VOCl2 + HCl-+2/+3: all trihalides known and are reducing Compounds with formula VX3 crystallize from H2O giving,         [VF3.(H2O)3] & for other halides [V(H2O)6]3+3X--All VX2 soluble in H2O and form violet solutions containing [V(H2O)6]2+-Addition of NaOH precips. V(OH)2 but compounds strongly reducing and sol. readily oxidised by air to [V(H2O)6]3+ H2O to produce H2

Chromium Chemistry

-Chromite (FeCr2O4) commercial ore -one method of extraction, reduction with coke in electric arc furnace--or converted to Cr2O3 & reduced by Al or Si-Cr2O3 + 2Al --> 2Cr + Al2O3-2CrO3 + 3Si --> 4Cr + 3SiO2Halides:-All CrX3 known and are coloured solids, prep. by reaction of  Cr + X2. hexaqua produced when dissolved in H2O, violet-CrX2 known and produced by reducing trihalides with H2 -CrCl2 gives sky-blue 2+hexaqua when dissolved in H2O - strong reducing agent 

Oxides--3 main oxides: Chromium sesquioxide:Cr2O3 (3+) green solid prep. by heating metal in air, by heating CrO3 or heating ammonium dichromate [NH4]2[Cr2O7] --> Cr2O3 + N2 + 4H2O(volcano experiment) Chromium dioxide: CrO2 +4 brown/black solid from CrO3 reduc. Chromium trioxide: CrO3 +4  deep red solid made by adding H2SO4 to Na2Cr2O7: H2SO4 + Na2Cr2O7 --> H20 + Na2SO4 + 2CrO3 CrO3 strongly acidic & dissolves in NaOH aq to form discrete tetrahedral chromate [CrO4]2-: CrO3 + 2NaOH --> 2Na+ [CrO4]2- + H2O Acidification of [CrO4]2- (yellow) give [Cr2O7]2- (orange/red) by joining two tetras pH > 8 CrO42- pH 2-6 HCrO4- & Cr2O72-  pH < 1 H2Cr2O7 

Manganese chemistry

-MnO2/Mn3O4 reduced with Al in blast furnace: 3MnO2 + 4Al --> 3Mn + 2Al2O3Halides: All halides known, most common --> MnF2, pale pink, MnF3,red/purple, MnF4,blue, MnCl2,pink,MnCl3, MnBr2,pink,MnI2,pink.Dihalides prep. by adding acid to MnCO3MnCO3 + 2HX --> MnX2 + CO2 + H2O-Or heat MnO2 with HCl to get MnCl2:MnO2 + 4HCl --> MnCl2 + 2H2O + Cl2

Oxides: diff. oxides dep. on ox. state of metal centre - Mn2O7,+7,green oil,MnO4,4+,Black solid,Mn2O3,+3,Black solid,Mn3O4,+2/3,black solid,MnO,+2,grey-green solid-oxi. of fused MnO2 with NaOH in air(or KNO3 as oxi agent) generates dark green manganate ion [MnO4]2-,+4, only stable in strongly alkali sols. & disproportionates in neutral/acidic sol--3[MnO4]2- + 4H+ --> 2[MnO4]- + MnO2 + 2H2O--manganate            --> permanganate(purple) due to transfer band not d-d transition good oxi agent--Redox properties of [MnO4]-:Strong base: [MnO4]- + e- --> [MnO4]2- fast, [MnO4]2- + 2H2O --> MnO2 + 4OH - slowModeate Base: [MnO4]2- + 2H2O + 3e- --> MnO2 + OH-Dil. H2SO4: [MnO4]- + 8H+ + 5e- --> Mn2+ + 4H2O

Iron Chemistry

Obtained from blast furnace: Fe2O3 + 3CO --> 2Fe + 3CO2Halides: get tri and di: tri - Fe + 3X2 -->2FeX3, di - Fe + HX --> FeX2--Oxides: Fe2O3,3+, red/brown, hematite, prep. heating alkaline sols. of Fe3+ & dehydrating solid formed; Fe3O4,2/3+, Black, magnetite; FeO,2+.Movement of Cl into alk. sol. of hydrated ferric oxide(Fe2O3), generates red/purple sol. that contains [FeO4]2- (ferrate), stronger oxidising agent that permanganate. Only stable in strongly alk. sol and decompose in water/acid[FeO4] 2- + 4H+ --> Fe3+ + O2 + 2H2O

General Fe Chem.Fe3+ strongly acidic: [Fe(OH2)6]3+ + H2O --> [Fe(OH2)5(OH)]2+ + H3O+ pKa 3.1.  [Fe(OH2)5(OH)]2+ + H2O --> [Fe(OH2)4(OH)2]+ + H3O+ pKa 3.3. --Rust: 2Fe --> 2Fe2+ + 4e- O2 + 2H2O + 4e- --> 4HO- overall: 2Fe + O2 + 2H2O --> 2Fe(OH02

Cobalt Chemistry

Extracted from sulphide by conversion to oxide then red. with H2/C:2Co2O3 +3C --> 4Co + 3CO2Halides: dihalides exist; CoF2,pink CoCl2,blue CoBr2,green CoI2,blue-black. CoCO3 + 2HX -->CoX2(aq) + CO2 + H2OHeat to get solid. Some other higher ox. state halides known:2CoCl2 + 3F2 --> 2CoF3 + 2Cl2

3 oxides:Co2O3,3+, prep by oxi. of Co(OH)2;Co3O4,2/3+,CoO,2++2 oxi. state: Hydrated salts of Co2+ pink/red, octahedrally coordCo(II) chloride tests for H2O as on dehydration pink Co hexaqua turns to blu tetrahedral ion.colour change due to crystal field splitting of E levels diff in oct and tetra cases. Though Co2+ more stable than Co3+ many Co(II) complexes readily oxidised to corresponding Co(III) complexes. Bc CFSE for Co(III) -d6 higher than for Co(II0 - d7 main reason for observation3+ oxi state: many stable Co(III) inert to ligand sub: Yellow [Co(NH3)6]3+,Pink[Co(NH3)5(OH2)]3+,Purple[Co(NH3)5(Cl)]2+,  Purple[Co(NH3)4(CO3)]+,Yellow[Co(NH3)3(NO2)3],violet[Co(CN)6]3-, yellow[Co(NO2)6]3-Linkade isomerism: can prep. nitrito ONO complex (red) but can be converted to yellow nitro NO2 complex by acid

Nickel Chemistry

Extraction: Ni occurs as Nis, NiAs2, & NiSb: sulphides roasted in air & converted to oxides. Oxides then red. to metal by C in smelterHalides: all Ni(II) halides known. NiCl2 when added to water forms, [Ni(OH2)6]2Cl- which is greenOxide: Oxide of Ni is NiO. when Ni reacts with fused NaOH in presence of O2, sodium nickelate - NaNi(III)O2 formed

Coordination complexes:Dominated by Ni(II). Wide range of geometries possible, including oct, square planar, tetra, trig bipy and square based pyramidal structurescomplexes with NH3, ethylene diamine oct and blue in colour, paramagnetic. Strong ligand i.e. CN-square planar complex formed: these are generally red, brown or yellow and are diamagenticNi(III) complexes less common: oxi. of Ni(OH)2 in alk. sol. with Br2 gives Ni2O3.2H2O as black solid which decomposes to NiO on dehydration.Macrocyclic ligand complexes capable of supporting 3+ oxi state

Copper Chemistry

Extraction: Cu occurs as CuFeS2, Cu2S & CuS in earth's crust. Sulfide ores conc. then roasted in air4CuFeS + 5O2 --> 2CuS + 2Fe2O3 + 2SO2Sand added to remove Fe as Fe2(SiO3)3 2Cu2S + 3O2 --> 2Cu2O + 2SO2Cu2S + 2Cu2O --> 6Cu + SO2Halides: Cu(I) halides cuprous, known (the F not been produced in pure state), colourless & diamagnetic. Cl and Br salts produced by boiling acidic sol of Cu(II) ion and excess of Cu. Upon dil. white CuCl or CuBr precip.Oxides: Cu(I) more stable than Cu(II) oxides at high temp. Cuprous oxide be prod. in controlled reaction of alk Cu(II) sol. Can also be prep by heating CuO at High Temp.CuO,2+ - Black solid, Cu2O,+ - red solid

Coordination complexes:In +1 ox state complexes diamagnetic and colourless as consequence of d10 config.Iodide ions reduce Cu2+ to CuI and I2 - cna be used to estimate Cu volumetrically as I easily titrated with Nathiosulphate:2Cu2+ + 4I- --> 2CuI + I2+2 ox state most stable and common for Cu. d9 config mans complexes paramagnetic and coloured. Hexaqua distorted oct with 2 long Cu-OH2 & 4 short Cu-OH2 bonds (Jahn-Teller Distortion)Aq Cu2+ sol form many complexes with amines ranging from:     [Cu(OH2)5NH3]2+[Cu(OH2)4(NH3)2]2+[Cu(OH2)3(NH3)3]2+[Cu(OH2)2(NH3)4]2+Anhydrous CuF2 & CuSO4 white as ligands weak & don't cause big ligand field splitting energy. Most other Cu(II) complexes blue/green. tetra[CuCl4]2- orange & Square planar[CuCl2]2- yellow

Zinc Chemistry

Extraction: Zinc occurs as ZnFeS & ZnS - to extract and purify, suphide taken to oxide and then reduced with CHalides: ZnX2. Zinc salts usually hydrated & dissolve in H2O to make 2+ hexaqua. Acidic due to eq[Zn(OH2)6]2+ --> [Zn(OH2)5(OH)]+ + H+

Oxides: only ZnO - yellow when hot and white when coldColour not a  d-d transition as completed shell - colour due to defects in solid structureCoordination complexes: Zinc(II) forms complexes with range of ligands inc. cyanide ammonia amines and halides. coord no.s 4 and 6 are common for Zn(II)