Coordination Chemistry22: Coordination ChemistryOxidation StatesOxidation StatesOxidation StatesIron & Steel: PyrometallurgyIron & Steel: PyrometallurgyIron & Steel: PyrometallurgyIron & SteelIron & SteelIron & SteelThe Metallurgy of CopperThe Metallurgy of CopperThe Metallurgy of CopperThe Metallurgy of CopperCopper: A Coinage MetalCopperCopperBronze & BrassCoordination ChemistryWhich transition metal has the electron configuration [Ar]3d3 in the +4 oxidation state?1. Cr4+2. Mn4+3. Fe4+4. Co4+22: Coordination Chemistry22.1 Properties of the Transition Elements 22.2 Iron and Steel: The Use of Pyrometallurgy22.3 Copper: A Coinage Metal22.4 Silver and Gold: The Other Coinage Metals22.5 Chromium22.6 Coordinate Covalent Bonds22.7 Crystal-Field TheoryMonday, November 3, 2014Read: Section 22.2 and 22.3 for Monday Sections 22.4, 22.5, and 22.6 for WednesdayEnd of Chapter 22 Problems: 8, 14, 16, 18, 20, 21, 22, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 63, 65, 67, 73, 75, 77, 78, 79, 83, 85, 91Monday, November 3, 2014Read: Section 22.2 and 22.3 for Monday Sections 22.4, 22.5, and 22.6 for WednesdayEnd of Chapter 22 Problems: 8, 14, 16, 18, 20, 21, 22, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 63, 65, 67, 73, 75, 77, 78, 79, 83, 85, 91Oxidation StatesTransition metal ion properties:•High ox. state compounds are strong oxidizing agents. Cr2O72- + 14 H3O+ + 6 e- → 2 Cr3+ + 21 H2O•Within the same element: Low ox. states are ionic; high ox. states are covalent.•MnCl2 solid contains Mn2+ and Cl- ions•MnO4- contains covalent Mn-O bondsOxidation StatesTransition metal ion properties:•Ions with a partially filled d-subshell make good catalysts.Zn2+Pt2+Pt0Oxidation StatesBiological Catalysts:•Iron can exist as Fe2+ or Fe3+ and acts as an electron shuttleIron-sulfur clustersIron & Steel: PyrometallurgyIron:•The most abundant transition metal•Soft and silvery whitePrincipal ores: hematite (Fe2O3); magnetite (Fe3O4)Pyrometallurgy = use high temperature to extract pure metal from its oresIn air: 4 Fe2+(aq) + O2(g) + 4 H+(g) → 4 Fe3+(aq) + 2 H2O(l)Rust: 2 Fe3+(aq) + 4 H2O(l) → Fe2O3·H2O(s) + 6 H+(aq)Iron & Steel: Pyrometallurgy2 C(s) + O2(g) → 2 CO(g) (exothermic)Fe2O3(s) + 3 CO(g) → 2 Fe(s) + 3 CO2(g)Silica impurities are removed by limestone:CaCO3(s) → CaO(s) + CO2(g)CaO(s) + SiO2(s) → CaSiO3(ℓ)Slag = liquid silicatesThe furnace makes pig ironPig iron is brittle because of impuritiesBlast FurnaceIron & Steel: PyrometallurgyCast iron = pig iron poured into molds The basic oxygen process makes steel. Pure O2 is blown through pig iron to remove impurities (limit C < 1.3%).Gas forms (C → CO, CO2; S → SO2)Occurs at ~1900 °CSteel composition is varied by adding other elements to get desired properties.Iron & SteelName Composition Properties UsesCarbon steel 1.3% C, 98.7% Fe Hard Sheet steel, toolsManganese 10-18% Mn, 90-82% FeHard, resistant to Railroad rails, safessteel 0.5% C wear armor plate.Stainless 14-18% Cr, 7-9% Ni, Resistant to Cutlery, instrumentssteel 79-73% Fe, 0.2% C corrosionNickel steel 2-4% Ni, 98-96% Fe Hard, elastic, Drive shafts, gears0.5% C resistant to corrosion cablesDuriron 12-15% Si, 88-85% Fe Resistant to Pipes0.85% C corrosion by acidsHigh-speed 14-20% W, 86-80% Fe Retains temper High-speed cuttingsteel 0.5% C when hot toolsIron & SteelToo much carbon in steel forms cementite (Fe3C) or graphite crystals.Cementite makes steel hard and brittle. Rapid cooling of hot steel (quenching) traps carbon as cementite. Slow cooling favors graphite formation, and a softer, more ductile material.Tempering (reheating and rapidly cooling) iron adjusts:•The graphite/cementite ratio.•The hardness.Iron & SteelThe amount of cementite produced may be decreased by lowering the temperature of the blast furnace. Is the formation of cementite exothermic or endothermic?1. Exothermic2. Endothermic if I lower the temperature I favor reactants, need to draw heat (exothermic process) from environment to make products (cementite)The Metallurgy of CopperCopper metal is sometimes found in nature10,000 years ago natural copper was used to make coins, jewelry, tools and weaponsToday, the demand for copper requires extraction from ores.3 FeS2(s) + 8 O2(g) Fe3O4(s) + 6 SiO2(g) 2 CuFeS2(s) + O2(g) Cu2S(s) + 2 FeS(s) + SO2(g)heatMajor ores: Chalcocite (Cu2S) and chalcopyrite (CuFeS2) are found mixed with FeS2 and FeS. Roasting:Native copperheatThe Metallurgy of CopperO2 and SiO2 produce iron silicate slag and Cu2S.Air is blown through the Cu2S: 2 Cu2S(ℓ) + 3 O2(g) 2 Cu2O(ℓ) + 2 SO2(g) 2 Cu2O(ℓ) + Cu2S(ℓ) 6 Cu(ℓ) + SO2(g)96 - 99.5% pure (blister copper)Open-pit copper mine inBingham CanyonCombining Fe3O4 with O2 and SiO2 forms iron slagThe Metallurgy of CopperRedox Returns!The voltage is controlled so that Cu, Zn, Pb, Fe dissolve from the anode.Reduction Half Reaction E° (V)Au+(aq) + e- → Au(s) +1.68Ag+(aq) + e-→ Ag(s) +0.799Cu2+(aq) + 2e-→ Cu(s) +0.337Fe2+(aq) + 2e-→ Fe(s) -0.44Pb2+(aq) + 2e-→ Pb(s) -0.126Zn2+(aq) + 2e-→ Zn(s) -0.763As the anode dissolves, Au, Ag and Pt drop out and form sludge.The Metallurgy of Copper•Au, Ag and Pt often pay for the refining!Cu2+ is reduced to Cu (99.9% pure) plates on the cathode.All other metal ions stay in solution.Copper is used in all U.S. coins.1 ¢ coin:•Until 1982: pure copper•Currently: zinc plated with copper(97.5% Zn, 2.5% Cu)The nickel is a uniform copper (75%) – nickel (25%) alloy.Other “silver” coins are a copper core covered with copper-nickel alloy.The Sacagawea dollar is coppercovered with a Mn-Cu-Zn alloy.Copper: A Coinage MetalCopper dissolves in nitric acid (but few other acids)Concentrated HNO3: Cu(s) + 2 NO3-(aq) + 4 H+(aq) → Cu2+(aq) + 2 NO2(g) + 2 H2O(ℓ)CuSO4•5H2O (blue vitriol) is widely used (fungicide, algicide). Aqueous solutions contain the blue [Cu(H2O)6]2+ complex.CopperbrownCu + HNO3(aq, conc): Brown NO2 fumes; green Cu(NO3)2(aq)CopperThe Cu(I) ion is unstable in water. It disproportionates DON’T FORGET THIS2 Cu+(aq) → Cu(s) + Cu2+(aq) E°cell = +0.37 V CuI Cu0 CuIIIn basic solution Cu2+ can be reduced to insoluble Cu2O•Used to test for glucose in urine. 2 Cu2+ + RCHO + 5 OH- → Cu2O + RCOO- + 3 H2O blue reducing sugar brick red When copper reacts with O2 at:•High T (>1000°C) black