第十四章碳族元素 Chapter 14 The carbon family elements Carbon(C) Silicon(Si) Germanium(Ge) Stannum(Sn) Tin Plumbum(Pb) Lead
第十四章 碳族元素 Chapter 14 The carbon family elements Carbon (C) Silicon (Si) Germanium (Ge) Stannum (Sn) Plumbum (Pb) Tin Lead
814-1Carbon and its compounds General properties 1.根据σ键的数目,碳可采取sp2、sp3杂化其最大配 位数为4 2.由于碳碳单键的键能特别大,所以C—C键非常稳定 ,具有形成均链的倾向 C-C N一N O-0 F一F E(kJ mol 374 250 210 159 实例H3C-CH3H2N-NH2HOOH 从碳到氮的单键键能的突减,是由于氮原子非键电 子对排斥的缘故
§14-1Carbon and its compounds 一、General properties 1. 根据σ键的数目,碳可采取sp2 、sp3杂化,其最大配 位数为4 2. 由于碳碳单键的键能特别大,所以C—C键非常稳定 ,具有形成均链的倾向 从碳到氮的单键键能的突减，是由于氮原子非键电 子对排斥的缘故。C－C N－N O－O F－F E (kJ·mol−1 ) 374 250 210 159 实 例 H3C－CH3 H2N－NH2 HO－OH
二、 Simple substance 1.在第二周期中,氟、氧、和氮都以双原子分子存在 F2、O2和N2;而碳存在多聚物,其理由为:O2和N2 的多重键要比σ单键(均键)强得多 Ooo O-0-0N≡N N一N一N E (kJ mol- 494>210+21 946 250+250+250 C=C—C-C-C E(kJ mol-)627 374+374 2. Allotropes: diamond graphite fullerene carbin(carbon fibers) (1) Carbin> Graphite Diamond (2 dc-c(nm): diamond> graphite carbin
二、Simple substance 1. 在第二周期中，氟、氧、和氮都以双原子分子存在 — F2、O2和N2；而碳存在多聚物，其理由为: O2和N2 的多重键要比σ单键(均键)强得多 2. Allotropes: diamond graphite fullerene carbin (carbon fibers) (1) 熵 Scarbin > Sgraphite > Sdiamond (2) dc-c (nm): diamond > graphite > carbin O O N N N N N C C C C C O O O E (kJ·mol−1 ) 494 ＞ 210 + 210, 946 ＞ 250 +250+250 E (kJ·mol−1 ) 627 ＜ 374 + 374
(3) Graphite- Diamond△H>0△s<0 根据平衡,需要高压6e9-1010Pa,( because of the insignificant reduction of volume),升高温度 不利于平衡的移动,但为了达到该过程可以接受的速率 ,反应温度大约在2000℃,近来已发明一种低压生产 金刚石的方法把金刚石晶种(seed放在气态碳氢化合 物(甲烷 methane, ethane)中,温度升高到1000℃,可 以得到金刚石粉末或者 crystal whiskers CVD technique for diamond growth
(3) Cgraphite Cdiamond ∆H > 0 ∆S < 0 根据平衡,需要高压6e9—1e10Pa，(because of the insignificant reduction of volume)，升高温度 不利于平衡的移动,但为了达到该过程可以接受的速率 ,反应温度大约在2000℃，近来已发明一种低压生产 金刚石的方法:把金刚石晶种(seed)放在气态碳氢化合 物( 甲烷methane, ethane )中,温度升高到1000℃,可 以得到金刚石粉末或者crystal whiskers CVD technique for diamond growth
Due to its combination of unique physical properties diamond is an outstanding H2, CH4 material. Besides its unrivaled hardness diamond exhibits ultrabroadband transparancy ranging from deep uv to the microwave regime, and a thermal conductivity at room temperature which is higher than that of any other material Microwave-Plasma The excellent mechanical. thermal optical and insulating properties of diamond became accessible through the =700-900°C advent of low pressure Chemical Vapour Deposition(CvD) techniques which allow diamond in the form of extended films and free-standing wafers to be fabricated The fundamental problem of diamond synthesis is the allotropic nature of carbon Under ordinary conditions graphite, not diamond, is the thermodynamically stable crystalline phase of carbon. Hence, the main requirement of diamond CVD is to deposit carbon and simultaneously suppress the formation of graphitic sp -bonds This can be realized by establishing high concentrations of non-diamond carbon etchants such as atomic hydrogen. Usually, those conditions are achieved by admixing large amounts of hydrogen to the process gas and by activating the gas either thermally or by a plasma
The fundamental problem of diamond synthesis is the allotropic nature of carbon. Under ordinary conditions graphite, not diamond, is the thermodynamically stable crystalline phase of carbon. Hence, the main requirement of diamond CVD is to deposit carbon and simultaneously suppress the formation of graphitic sp2 -bonds. This can be realized by establishing high concentrations of non-diamond carbon etchants such as atomic hydrogen. Usually, those conditions are achieved by admixing large amounts of hydrogen to the process gas and by activating the gas either thermally or by a plasma. Due to its combination of unique physical properties diamond is an outstanding material. Besides its unrivaled hardness diamond exhibits ultrabroadband transparancy ranging from deep UV to the microwave regime, and a thermal conductivity at room temperature which is higher than that of any other material. The excellent mechanical, thermal, optical and insulating properties of diamond became accessible through the advent of low pressure Chemical Vapour Deposition (CVD) techniques which allow diamond in the form of extended films and free-standing wafers to be fabricated
(4)C60 由12个五边形和20个六边形组成每个该原子以sp2 杂化轨道与相邻的三个碳原子相连,剩余的p轨道在 c60球壳的外围和内腔形成球面T键,从而具有芳香性 欧拉方程:面数(F)+顶点数(Ⅵ)=棱数(E)+2 a. structure:根据欧拉定理,通过12个五边形和数 个六边形的连接可以形成封闭的多面体结构 c0为第一个五边形间互不相邻的碳笼 不存在六边形的最小碳笼为C20
(4) C60 由12个五边形和20个六边形组成,每个该原子以sp2 杂化轨道与相邻的三个碳原子相连，剩余的p轨道在 C60球壳的外围和内腔形成球面π键,从而具有芳香性 欧拉方程：面数(F) + 顶点数(V) = 棱数(E) + 2 a. structure:根据欧拉定理，通过12个五边形和数 个六边形的连接可以形成封闭的多面体结构 C60为第一个五边形间互不相邻的碳笼 不存在六边形的最小碳笼为C20
32个面,60个顶点,90条棱 12个正五边形和20个正六边形 F+VEE+2
32个面，60个顶点，90条棱 12个正五边形和20个正六边形 F + V = E + 2
Fullerene Discoverers Win Chemistry Nobel The Nobel Prize in chemistry was awarded today to two Americans and one British researcher for their discovery of fullerenes, a new class of all-carbon molecules shaped like hollow balls The researchers, Richard E. Smalley and Robert F Curl Jr of Rice University in Houston, and Harold w. Kroto of the University of Sussex in Brighton, United Kingdom, made their discovery in 1985 in Smalley's lab at Rice while working together to study how carbon atoms cluster. The award is richly deserved, says Robert Haddon, a fullerene chemist at Lucent Technologies Bell Labs in Murray Hill, New Jersey. " It led to a totally new field of chemistry. Today, fullerenes--which are popularly known as buckyballs--are being investigated for everything from new superconductors and three-dimensional polymers, to catalysts and optical materials, although they have yet to spawn any commercial applications Before the group's discovery, crystalline carbon was thought to adopt only a handful of different molecular architectures, including those found in diamond and graphite. But the researchers discovered that sheets of carbon atoms arranged in a pattern of hexagons and pentagons can curl up and ultimately close to form hollow cages. And because the number of atoms in the cage can vary, an almost infinite number of fullerene shapes may exist
Fullerene Discoverers Win Chemistry Nobel The Nobel Prize in chemistry was awarded today to two Americans and one British researcher for their discovery of fullerenes, a new class of all-carbon molecules shaped like hollow balls. The researchers, Richard E. Smalley and Robert F. Curl Jr. of Rice University in Houston, and Harold W. Kroto of the University of Sussex in Brighton, United Kingdom, made their discovery in 1985 in Smalley's lab at Rice while working together to study how carbon atoms cluster. "The award is richly deserved," says Robert Haddon, a fullerene chemist at Lucent Technologies' Bell Labs in Murray Hill, New Jersey. "It led to a totally new field of chemistry." Today, fullerenes--which are popularly known as buckyballs--are being investigated for everything from new superconductors and three-dimensional polymers, to catalysts and optical materials, although they have yet to spawn any commercial applications. Before the group's discovery, crystalline carbon was thought to adopt only a handful of different molecular architectures, including those found in diamond and graphite. But the researchers discovered that sheets of carbon atoms arranged in a pattern of hexagons and pentagons can curl up and ultimately close to form hollow cages. And because the number of atoms in the cage can vary, an almost infinite number of fullerene shapes may exist
The platonic polydedra:f=2+evF分V;C分E;P分F Tetrahedron Cube Octahedron Dodecahedron Icosahedron .Triangles. The interior angle of an equilateral triangle is 60 degrees thus on a regular polyhedron, only 3, 4, or 5 triangles can meet a vertex. If there were more than 6 their angles would add up to at least 360 degrees which they cant. Consider the possibilities .3 triangles meet at each vertex. This gives rise to a Tetrahedron .4 triangles meet at each vertex. This gives rise to an Octahedron .5 triangles meet at each vertex. This gives rise to an Icosahedron .Squares. Since the interior angle of a square is 90 degrees, at most three squares can meet at a vertex. this is indeed possible and it gives rise to a hexahedron or cube Pentagons. As in the case of cubes, the only possibility is that three pentagons meet at a vertex. This gives rise to a Dodecahedron Hexagons or regular polygons with more than six sides cannot form the faces of a regular polyhedron since their interior angles are at least 120 degrees
Tetrahedron Cube Octahedron Dodecahedron Icosahedron •Triangles. The interior angle of an equilateral triangle is 60 degrees. Thus on a regular polyhedron, only 3, 4, or 5 triangles can meet a vertex. If there were more than 6 their angles would add up to at least 360 degrees which they can't. Consider the possibilities: •3 triangles meet at each vertex. This gives rise to a Tetrahedron. •4 triangles meet at each vertex. This gives rise to an Octahedron. •5 triangles meet at each vertex. This gives rise to an Icosahedron •Squares.Since the interior angle of a square is 90 degrees, at most three squares can meet at a vertex. This is indeed possible and it gives rise to a hexahedron or cube. •Pentagons.As in the case of cubes, the only possibility is that three pentagons meet at a vertex. This gives rise to a Dodecahedron. •Hexagons or regular polygons with more than six sides cannot form the faces of a regular polyhedron since their interior angles are at least 120 degrees. The Platonic Polydedra: f=2+e-v
b. properties:科学家认为c0将是21世纪的重要 材料 ()c60分子具有球形的芳香性,可以合成C0F2,作 为超级润滑剂 (i)cso笼内可以填入金属原子而形成超原子分子, 作为新型催化剂或催化剂载体,具有超导性 ic0体有金属光泽,其微晶体粉末呈黄色, 易溶于苯,其苯溶液呈紫红色。c60分子特别稳定,进 行化学反应时,c60始终是一个整体
b. properties: 科学家认为C60将是21世纪的重要 材料 (i) C60分子具有球形的芳香性,可以合成C60F2 ，作 为超级润滑剂 (ii) C60笼内可以填入金属原子而形成超原子分子, 作为新型催化剂或催化剂载体，具有超导性 (iii) C60晶体有金属光泽，其微晶体粉末呈黄色， 易溶于苯，其苯溶液呈紫红色。C60分子特别稳定，进 行化学反应时，C60始终是一个整体