《过渡金属的特性》PPT课件.ppt

“Transition” metals,过渡金属的特性,变价性 配合物 颜色 磁性 From highly reactive metals of the s block to the much less reactive metals of Group 12 and the p block.,Trends in Physical Properties,All the d-block elements are metals. Most, good electrical conductors. Most, malleable, ductile(延展), lustrous(光泽), silver-white in color. Generally, higher melting and boiling points. 例外: Hg, low melting point, Liquid(RT) Cu, red-brown and Au, yellow.,The lobes of two d-orbitals on the same atom occupy markedly different regions of the space. Relatively far apart, repel one another weakly. 分占不同的区域， 相对远离，互斥小。 2) Electron density in d-orbitals is low near nucleus. Not very effective at shielding other electrons from the nuclear charge. 接近核处电子密度低， 屏蔽弱,Nuclear charge and the number of d-electrons both increase from left to right across each row. Because the repulsion between d-electrons is weak, the increasing nuclear charge can draw them inward, so the atom becomes smaller. Further across the block, the radii begin to increase slightly. There are so many d-electrons that the e-e repulsion increase more than the effective nuclear charge.,Because the atomic radii of the d-block elements are so similar the atoms of one element can replace the atoms of another element with minor modification of the atomic locations. Consequently, a wide range of alloys can form.,Atomic radii of the d-block elements (pm). Notice the similarity of all the values and, in particular, the close similarity between the second and third rows as a result of the lanthanide contraction. (From 224pm for Ba to 172pm for Lu) (higher nuclear charge and the poor shielding effect of the f-electrons),La-Lu,The densities (g/cm3) of d-metals at 25C. The lanthanide contraction has a pronounced effect on the densities of the elements in Period 6, which are among the densest of all the elements.,Ferromagnetic materials include Fe, Co, Ni, Gd, CrO2, magnetite. They contain regions of atom in which electrons of many atoms spin in the same direction and give rise to a strong magnetic field. Before magnetization, the spins are almost randomly aligned. After magnetization the spins are aligned in the same direction.,Trends in Chemical Properties,The range of oxidation states of each d-metals. At the ends of each row (Sc, Zn), in one oxidation state other than zero. Close the center of each row, in at least two oxidation states (Mn). The second, and third rows, higher oxidation states. A species in which an element is in a high oxidation state tends to be a good oxidizing agent. MnO4-(aq)+8H+(aq)+5e- Mn2+(aq)+4H2O(l) Eo=+1.51V Most d-metal oxides are basic, the oxides of a given element show a shift toward acidic character with increasing oxidation number. Cr(II)O Cr2(III)O3 Cr(VI)O3 basic amphoteric acidic,四,五,六,周期,These three artifacts represent the progress that has been made in the extraction of d-metals.(a) An ancient bronze (青铜，Cu/Sn) chariot axle cap from China, made from an alloy of metals hat are easy to extract. (b) A nineteenth-century iron steam engine made from a metal that was moderately easy to extract once high temperatures could be achieved. (c) A 20-century airplane engine with titanium components that had to await advanced, high-temperature technology before the element became widely available.,Scandium through Nickel,前过渡元素,后过渡元素,Scandium, Sc Isolated in 1937, a reactive metal. Sc react with water about as vigorously as Ca does. The small, highly charged Sc3+ ion is strongly hydrated in water (like Al3+), the resulting hydrated ion is about as strong a Bronsted acid as acetic acid.,Titanium, Ti Light, strong metal (vital in airplane). Resistant to corrosion. Ores: ilmenite (钛铁矿), FeTiO3 Rutile(金红石), TiO2 Ti requires strong reducing agents for extraction from its ores. Ores +Cl2 TiCl4 TiCl4(g) + 2Mg(l) 700C Ti(s) + 2MgCl2(s),TiO2 brilliantly white, nontoxic, stable solid used as white pigment in paints and paper. Semiconductor in the presence of light, used as electrode in photoelectrochemical cells. BaTiO3, piezoelectric(压电).,Vanadium, V V2O5(s) + 5 Ca(l) 2V(s) + 5CaO(s) or VCl2(s) + Mg(l) V(s) + MgCl2(s) or electrolysis Ferrovanadium, V 86%, C 12%, Fe 2%. + Fe,C(l) V steel Tough steels for automobile and truck springs. V2O5, the most important compound of vanadium. Used as an oxidizing agent and as oxidizing catalyst in the contact process for the manufacture of sulfuric acid. The wide range of colors of V compounds, including the blue of vanadyl ion, VO2+, has led to their use as glazes(釉料) in the ceramic industry.,S + O2 SO2; 植被分解和火山爆发；燃油和煤(电厂) H2S(g) + 3O2(g) 2SO2(g) + 2H2O(g) 酸性氧化物 SO2(g) + H2O(l) H2SO3(aq) 还原性和氧化性 SO2(g) + Br2(aq) Br-(aq) + SO4-(aq) 2SO2(g) + O2(g) 2SO3(g), slow reaction, catalyzed V2O5 SO3(g) + H2O(l) H2SO4(aq) 酸雨（Sox, Nox, H2O） H2SO4, 无色腐蚀油状液体；强酸，脱水剂，氧化剂。 SO3(g) + H2SO4(l) H2S2O7(l) (Oleum, 发烟硫酸) 化肥（2/3），石化产品，染料，清洁剂。,SO2，SO3, H2S(IV)O3, H2S(VI)O4,VO43-,VO2+,V3+,V2+,+5, +4, +3, +2,MnO4- MnO2 VO43- VO2+ V3+ V2+,锌汞齐,Chromium, Cr (the name comes from chroma, Greek for color) Bright, lustrous, corrosion-resistant metal. FeCr2O4(s) + 4C(s) Fe(s) + 2Cr(s) + 4CO(g) or Cr2O3(s) + Al(s) Al2O3(s) + 2Cr(l) (thermite 铝热 process) Cr metal, mostly, used in steel making and for Cr plating. CrO2, a ferromagnetic materials used for coating “chrome” recording tapes because they respond better to high-frequency magnetic fields than do conventional “ferric” (-Fe2O3) tapes.,2CrO42- (aq) + 2H+(aq) Cr2O72-(aq) + H2O(l) Cr2O72-(aq)+14H+(aq)+6e- 2Cr3+(aq)+7H2O(l) Eo= +1.33V,(NH4)2CrO4热分解 （火山实验）,Cr(III)和Cr(VI)的相互转换 元素电势图的应用,Manganese, Mn Gray metal that resembles iron. Rarely used alone, much less resistant to corrosion. Important component of alloys. In steelmaking, it removes S. 3MnO2(s)+4Al(s) 2Al2O3(s)+3Mn(l) (thermite 铝热 process) MnO2, a brown-black solid used in dry cells; as a decolorizer to conceal the green tint of glass; as the starting point for other Mn compounds. KMnO4, a widely used strong oxidizing agent in acidic solution. Also as a mild disinfectant (消毒剂).,Manganese nodules (锰结核?),MnO2+KOH K2MnO4,K2MnO4 + H+ KMnO4 + MnO2,Mn的不同氧化态,Rational synthetic reactions to MnO2,MnSO4 + (NH4)2S2O8 MnO2 nanobelts MnSO4 + NaClO MnO2 nanorods MnSO4 + H2O2 MnO2 nanorods 2KMnO4 +3MnSO4 5MnO2 nanowires Mn2+2OH- Mn(OH)2 MnO(OH) nanowires NaMnO2 MnO2 nanotubes,1-D nanostructures in Manganese dioxides,NaMnO2,delta-MnO2,alpha-MnO2,gammar-MnO2,beta-MnO2,Structures of Manganese oxides,MnSO4 + (NH4)2S2O8 MnO2,Wang Xun, Li Yadong, J.Am.Chem.Soc, 2002,124, 2880,2KMnO4 +3MnSO4 + 2H2O 5MnO2 + K2SO4 + 2H2SO4,Wang Xun and Li Yadong. Chem Commun, 2002, 764,Formation mechanism of MnO2 nanowires,From layer structure to nanowires- Rolling mechanism,Wang Xun, Li Yadong, Eur. J. Chem, 2003, 9, 300,MnO2 Nanotubes,Iron, Fe The most widely used of all the d-metals. The most abundant on Earth as a whole, and the second most abundant metal in Earth crust (Al, No. 1 metal). Hematite(赤铁矿), Fe2O3; magnetite(磁铁矿), Fe3O4; pyrite(黄铁矿), FeS2. Fe2O3(s)+3CO(g) 2Fe(l)+3CO2(g) (Fe/kg requires ca. 1.75Kg ore, 0.75Kg coke, 0.25kg limestone.) A healthy adult human body contains ca. 3g of iron, mostly as hemoglobin(血色素). Close to 1mg is lost daily(in sweat, feces, hair), must be ingested daily. Iron deficiency, in reduced transport of oxygen to the brain and muscles, an early symptom is chronic tiredness(持续疲倦).,Blast furnace (鼓风炉) CaO(s)+SiO2(s) CaSiO3(l) CaO(s)+Al2O3(s) Ca(AlO2)2(l) 6CaO(s)+P4O10(s) 2Ca3(PO4)2(l) Slag(炉渣),矿，焦碳，石灰石,炉渣,Basic oxygen process （炼钢） A blast of oxygen and powdered limestone is used to purify molten iron by, respectively, oxidizing and combining with the impurities present in it.,Fe(II)和Fe(III)的配合物 K4Fe(CN)6 + Fe3+ 普鲁士蓝(Prussian Blue) (黄血盐, 亚铁氰化钾) K3Fe(CN)6 + Fe2+ 滕氏蓝(Turnbulls Blue) (赤血盐, 铁氰化钾),同一种物质？ 价态与自旋态,X-射线衍射分析,穆斯鲍尔谱,KFeFe(CN)6 nH2O,普鲁士蓝与滕氏蓝的结构,1/8 结构单元,Cobalt, Co Oren are often found in association with copper(II) sulfide. Silver-gray metal, used mainly for alloying with Fe. Alnico(磁钢)，an alloy of Fe, Ni, Co, Al. Cobalt steel are hard enough to be used as surgical(外科) steels. Co(II) oxide is heated with Si and Al to produce a blue pigment used to color glass and ceramic glazes. We need cobalt in our diet(食物), for it is a component of Vitamin B12.,CoCl2 + (NH4)2S CoS CoCl2 + NaOH Co(OH)2 Co(OH)2 +H2O2 Co(OH)3,Nickel, Ni Also used to alloy with iron. Ca. 70% Ni (西方) supply comes from Fe and Ni sulfide ores. Ni(s) + 4CO(g) 50C Ni(CO)4(g) (Mond process) Volatile, poisonous liquid, boils at 43C. Reverse the reaction at ca. 200C. Cupronickels(白铜)，25%Ni, 75%Cu, for Ni coins. Catalyst, especially for the addition of hydrogen to organic compounds, for example, in the manufacture of edible solid fats (食用油脂) from vegetable oils.,NiO,d区元素的羰基化合物 (Carbonyl Compounds),分子轨道：,CO的成键特点？ 与N2类似,Lewis结构：,d区元素的羰基化合物(Carbonyl Compounds),NiCl2 + (NH4)2S NiS NiCl2 + NaOH Ni(OH)2,The d-block elements Ti through Ni are ob