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Iron (Fe)

Iron (Fe). Electron configuration: 4s 2 3d 6  4s 1 3d 6 3d 6 3d 5 Iiron(II): ferrous, ferro; Iiron(II): ferric, ferri Ores: Hematite: Fe 2 O 3 (impure) Limonite: FeO(OH) . n H 2 O Magnitite: Fe 3 O 4 Siderite: FeCO 3. Iron (Fe) (p339). Properties Very abundant

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Iron (Fe)

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  1. Iron (Fe) • Electron configuration: 4s23d64s13d63d63d5 • Iiron(II): ferrous, ferro; Iiron(II): ferric, ferri • Ores: • Hematite: Fe2O3 (impure) • Limonite: FeO(OH).nH2O • Magnitite: Fe3O4 • Siderite: FeCO3

  2. Iron (Fe) (p339) • Properties • Very abundant • Main oxidation states: II, III. VI is rare (FeO42–) • Can be magnetized. • Uses • Not very useful in “pure” form, used to make steel by mixing with a small amount of carbon. • Iron oxides are used as pigments. • Has immense biological importance.

  3. Binary compounds (p339) • Fe(OH)2 (pale green) is easily oxidized by air to give red-brown hydrous iron (II) oxide. Fe(OH)2, like Fe(OH)3, is somewhat amphoteric, react with hot conc. NaOH to form Fe(OH)64–. • FeO is usually nonstoichiometric, Fe0.95O. • Fe2O3 has two crystal forms: α(as pigment),γ (as magnetic materia)

  4. Binary compounds (p339) • Fe3O4 can be presented as Fe[Fe2O4], having an inverse spinel structure. Cl2 HCl FeCl3·6H2O Fe FeCl2 Cl2 FeCl3 quite readily hydrolyzes in water. Fe(H2O)63+ is pale purple.

  5. Complexes (p340, p341) • The affinity of Fe(III) for NH3 and amine is low except for chelates, such as edta, bipy, phen. FeF63–, Fe(H2O)1–n(SCN)n3–n • Fe(II)-Fe(III) system provides an excellent example of the effect of ligands on the relative stabilities of oxidation states: Eº(Fe(H2O)63+/2+) = 0.77 V Eº(Fe(phen)33+/2+) = 1.12 V Eº(Fe(CN)63–/4–) = 0.36 V

  6. Potential-pH diagram for Fe-H2O system

  7. Ferrocene: a sandwich compound Chemistry of Ferrocene Metallocenes undergo reactions similar to those of simple aromatic hydrocarbons.

  8. Possible structures of [Fe(5-C5H5)2]

  9. Cobalt (Co) • Electron configuration: 4s23d73d83d73d6 • Properties • Hard, brittle, lustrous blue-white. • Main oxidation state: II • Ores: Cobaltite CoAsS

  10. Cobalt (p342) • Uses • Used as an alloy in magnets, jet engine parts. • Used in electroplating because of its attractive appearance, hardness and resistance to oxidation. • Vitamin B12 is a cobalt complex. • Cobalt salts have been used for centuries to produce brilliant blue colors in porcelain, glass, pottery and enamels. • The artificial isotope 60Co is used as a tracer.

  11. The element cobalt (p342) • The trends toward decreased stability of the very oxidation states and the increased stability of the II state relative to the III state, which occur through the series Ti, V, Cr, Mn, and Fe, persist with Co. The higest oxidation state is now IV, and only a few such compounds are known. Cobalt (II) is relatively unstable in simple compounds, but…

  12. Chemistry of Cobalt

  13. With sodium hydroxide solution and hydrogen peroxide etc.

  14. Complexes (p343) • Co(II) complexes may be either octahedral or tetrahedral. Co(H2O)62+ Co(H2O)42+ + 2H2O Co(H2O)62+ + 4Cl– =CoCl42– + 6H2O • Co(II) forms tetrahedral complexes more readily than any other transition metal ion. Two factors: Δ(CFSE) = 2/10 ΔO X–, having negative charge

  15. Complexes (p344) • The Co3+ ion shows a particular affinity for N donors, such as NH3, en, edta, CN–, NCS–, and complexes are exceedingly numerous. • All complexes, except the one with F–, are low-spin. • They generally undergo ligand-exchange reactions relatively slowly, like Cr3+, Rh3+.

  16. Complexes (p344) • Important to isomerism, modes of reaction, and general properties of octahedral complexes. Almost all Co(III) complexes are octahedral. • Co(III) complexes are syntheszed by oxidation of Co(II) in solution in the presence of the ligands. O2 or H2O2 and a catalyst, such as activated charcoal, are used. Adducts and peroxo-bridged species.

  17. Nickel (Ni) • Electron Configuration: 4s23d83d93d83d7 • The name is a shortened version of the German ‘Kupfernickel’, meaning Devil’s copper or St. Nicholas’s copper.

  18. Nickel • Properties • Hard, malleable and ductile, silvery-white, capable of taking on a high polish. • Main oxidation state: II • Soluble in all acids except concentrated nitric acid. • Nickel carbonyl is very toxic.

  19. Nickel • Uses: • Used extensively in alloys: stainless steel, coinage metals. • The Nickel is 25% nickel and 75% copper • Electroplated Ni gives a protective coat for other metals. • Rechargeable batteries (Ni-Mn, NiCd)

  20. Complexes (p347) • Ni(II) forms complexes with coordination number 6, 5, and 4 having all the main structural types: octahedral. Trigonal bipyramidal, square pyramidal, tetrahedral, and square. • Their characters are complicated equilibrium with temperature, concentration.

  21. Four-coordinate complexes (p347) • d8 configuration: dsp2 hybridization, or low-spin state. • Ligands forming Conjugating system with metal: acac, dimethylglyoximato • Ligands belonging the type ofπ-acid ligand: CN–, SCN– • But halides, X–; large ligands: PR3, OPR3

  22. Conformational properties of nickel (II) complexes (p349) • Formation of five- and six-coordinate complexes results from the addition of ligands to square complexes. Solvents, anions, ligands • Monomer-polymer equilibria: four coordinate complexes with a donor atom having another more lone pare. • Square-tetrahedral equilibria and isomerism: NiL2X2 (L = PR3), two crystalline forms.

  23. Copper (Cu) • Electron configuration: 4s13d103d103d93d8 • Properties • Malleable and ductile; reddish. • Good conductor of heat and electricity. • Main oxidation state: II, I, and III

  24. Copper • Ores: • Chalcopyrite: CuFeS2 • Cuprite: Cu2O • Bornite Cu3FeS4 • Azurite: Cu3(CO3)2(OH)2 • Covellite: Cu2S

  25. Copper • Uses • Electrical wires and switches, plumbing, cooking vessels. • Used as an alloy: brass (Cu/Zn), Bronze (Cu/Sn), Coinage material (Cu/Ni). • Copper sulphate is used widely as an agricultural poison and as an algaecide in water purification.

  26. Copper • Copper is relatively rare, accounting for about 0.0068% of the earth's crust by mass. • Copper is found in its elemental state, as are other group 1B elements. Malachite 孔雀石

  27. How copper is made? Copper ore, in concentrations ranging from 0.29 percent to ten times that amount, is mined from open pit or underground mines The Mine ore is transported to the crushing plant where it is crushed to a size appropriate for the grinding process and then conveyed to the concentrator.

  28. The crushed mine ore is ground in rod and ball mills and then sent to flotation machines where the copper mineral rises to the top in a froth, making a copper concentrate of approximately 30 percent, 27 percent iron and 33 percent sulfur. After a series of runs through furnaces, where non-copper elements are burned off or separated, the result is a 99 percent pure molten copper, know as "blister". Blister is poured into anode molds.

  29. In an electrolyte of sulfuric acid, copper sulfate and plating reagents, copper is transferred from an anode at the positive pole of an electric circuit to the cathode at the negative pole. The result is 99.9999 percent pure copper. While some cathode can be shipped directly to customers, other can be sent to a rod plant

  30. OXIDE LEACHING AND SOLVENT EXTRACTION-ELECTROWINNING (SX-EW) Copper oxide ore is piled onto thick high density polyethylene liner. Sprinklers placed on the surface spray a weak acid solution, which dissolves the acid-soluble copper in the ore. The copper bearing solutions are collected and pumped to a solvent extraction plant where an organic extractant removes the copper from the solution. The resulting electrolyte solution is transferred to the electrowinning process where copper is plated out as a cathode.

  31. The chemistry of copper(I) (p351) • d10, colorless, except charge-transfer band • K = 1E6 for the disproportiation of Cu+, Why ? • Lattice energy • Solvation energy, CFSE 0.153 0.52 Cu2+ Cu+ Cu

  32. The factors for stabling Cu+: • precipitant: X–, to give CuX, (CH3)2S, to give Cu2S • In drying state: Cu2O • Non-chelate ligands such as ammonia, pentamethylenediamine, acetonitrile

  33. The chemistry of copper(I) (p351) • Important properties: • Cu(NH3)22+ + NH3·H2O + O2 → Cu(NH3)42+ • CuI + Hg → Cu2HgI4 • CuCl + CO → Cu2(CO)2Cl2(H2O)2

  34. The chemistry of copper(II) (p353) • d9, blue • Distorted octehedral or tetrahedral complexes, planar complexes • In distorted octehadral complexes, there are four short Cu─L bonds in the plane and two trans long ones, which leads to a situation indistinguishable from square coordination, as found in CuO, or for Cu(NH3)42+, Cu(H2O)42+,

  35. The chemistry of copper(II) (p354) • Distorted tetrahedral complexes: M(I)2CuX4 (M(I), large cationic ion) • But (NH4)2CuX4, having a planar anion • Halides (no iodide): CuCl2, yellow, and CuBr2, black. They have structures with infinite parallel bands of square CuX4 units sharing edges, making a tetragonally elongated octahedron. They readily soluble in donor solvents.

  36. The chemistry of copper(II) (p355) • Cu2(OOCR)2·2H2O O O O O H2O Cu Cu OH2 O O O O

  37. Silver - Ag • Sterling silver contains 92.5% silver, the remainder being copper or some other metal, and is used for jewelry and silverware where appearance is important. • About 30% of silver produced is used in the photographic industry, mostly as silver (I) nitrate.

  38. Silver • Silver is used in dental alloys, solder and brazing alloys, electrical contacts and batteries. • Silver paints are used for making printed circuits. • Used to make mirrors, as it is the best reflector of visible light known, although it does tarnish with time.

  39. Silver • A suspected carcinogen. • Silver compounds can be absorbed in the circulatory system and reduced silver deposited in various organs. • This results in greyish pigmentation of the skin and mucous membranes, known as argyria. • Silver has germicidal effects - it can kill lower organisms quite effectively.

  40. Silver • Silver is stable to water and oxygen but is attacked by sulfur compounds in air to form a black sulphide layer. It dissolves in sulfuric and nitric acids. It is a little harder than gold and is extremely ductile and malleable. Pure silver has the highest electrical and thermal conductivity of all metals, and has the lowest contact resistance

  41. Silver (p383) • Ag(I) is the most stable and important oxidation state. • Silver is very sensitive to S and H2S, the reaction gives Ag2S, which can be readily reduced by contact with aluminum in dilute sodinium carbonate solution. • Halides: AgX, color, solubilities • Complexes: NH3, S2O32–, CN– Ag2S

  42. Silver (p383) • Complexes: • AgXn1–n, making AgX dissolve in solution with excess halide. • Ag(NH3)2+ can react with the base solution of aldehyde to give “silver mirror”. Note: The left solution of Ag(NH3)2+ can not be maintained, because the solution will decompose to give explosive Ag3N.

  43. Gold - Au • It is a soft metal with a characteristic yellow color and sheen. • Gold is used for coinage and is a standard for monetary systems in many countries. • It is used extensively in jewelry. • The term carat expresses the amount of gold present in an alloy; 24 carat is pure gold.

  44. Gold (p384) • Gold is used in dental work. • A gold compound is used in certain cases to treat arthritis. • Another gold compound is used in photography for toning the silver image. • Gold has the highest malleability and ductility of any element.

  45. Gold (p384) • It is a good conductor of heat and electricity. • It is also a good reflector of infra-red radiation, and as it is inert makes an excellent coating for space satellites. • The stable oxidation state: III, I

  46. Gold compounds (p384) • Au(CN)2– is readil formed by dissolving gold in cyanide solutions in the presence of air. • Dissolution of gold in aqua regia gives a solution that on evaporation deposits yellow crystals of [H3O][AuCl4]·3H2O. • AuCl4– is a planar anion (d8), many other salts having a square planar geometrical anion can obtained from this anion: X–, CN–, SCN–, NO3–

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