化学专业英语翻译(修订版)02非金属元素

化学专业英语翻译(校准版) 02 THE NONMETAL ELEMENTS 02非金属元素 We noted earlier. that -nonmetals exhibit properties that are greatly different from those of the metals. As a rule, the nonmetals are poor conductors of electricity (graphitic carbon is an exception) and heat; they are brittle, are often intensely colored, and show an unusually wide range of melting and boiling points. Their molecular structures, usually involving ordinary covalent bonds, vary from the simple diatomic molecules of H2, Cl2, I2, and N2 to the giant molecules of diamond, silicon and boron. 我们早知道非金属表现出来的性质是和金属大不相同的。一般来说,非金属是电与热的不良导体,石墨例外;他们是易碎的,通常呈现深颜色,并表现出异常广泛的熔点和沸点。他们的分子结构通常涉及到共价键的变化,包括简单的双原子分子氢气、氯气、碘和氮气,和巨大的金刚石、硅和硼。 The nonmetals that are gases at room temperature are the low-molecular weight diatomic molecules and the noble gases that exert very small intermolecular forces. As the molecular weight increases, we encounter a liquid (Br2) and a solid (I2) whose vapor pressures also indicate small intermolecular forces. Certain properties of a few nonmetals are listed in Table 2. 在室温下,低分子量的双原子分子的气态非金属和惰性气体相遇会产生非常小的分子间作用力。随着分子量的增大,我们知道液体(Br2)和固体(碘)的蒸汽压也表现出较小的分子间作用力。一些非金属的某些性质列在表2中。 Simple diatomic molecules are not formed by the heavier members of Groups V and VI at ordinary conditions. This is in direct contrast to the first members of these groups, N2 and O2. The difference arises because of the lower stability of πbonds formed from p orbitals of the third and higher main energy levels as opposed to the second main energy level2. The larger atomic radii and more dense electron clouds of elements of the third period and higher do not allow good parallel overlap of p orbitals necessary for a strong πbond. This is a general phenomenon —strong πbonds are formed only between elements of the second period. Thus, elemental nitrogen and oxygen form stable molecules with both σand πbonds, but other members of their groups form more stable structures based on σbonds only at ordinary conditions. Note3 that Group VII elements form diatomic molecules, but πbonds are not required for saturation of valence. 一般情况下,简单的双原子分子并不是由分子量大的第五主族和第六主族组成的。直接对比这两组的第一个成员,氮气和氧气;差别产生是因为形成p轨道的∏键的第三和更高的主要能量水平相对于第二个主要能量水平稳定性较低。第三周期具有较大原子半径和电子云更加密集的元素和更高的不允许平行的p轨道很好地重叠成一个强大的π键。这是一个普遍的现象——强π键仅由第二周期的元素形成。因此,氮和氧元素基本上都是通过σ和π键形成稳定的分子,但同族的元素一般情况下以σ键为基础形成更稳定的结构。值得注意的是,第七主族的元素形成双原子分子,但π键不要求形成饱和的共价键。 Sulfur exhibits allotropic forms. Solid sulfur exists in two crystalline forms and in an amorphous form. Rhombic sulfur is obtained by crystallization from a suitable solution, such as CS2, and it melts at 112°C. Monoclinic sulfur is formed by cooling melted sulfur and it melts at 119°C. Both forms of crystalline sulfur melt into S-gamma, which is composed of S8 molecules. The S8 molecules are puckered rings and survive heating to about 160°C. Above 160°C, the S8 rings break open, and some of these fragments combine with each other to form a highly viscous mixture of irregularly shaped coils. At a range of higher temperatures the liquid sulfur becomes so viscous that it will not pour from its container. The color also changes from straw yellow at sulfur's melting point to a deep reddish-brown as it becomes more viscous. 硫有同素异形体,固体硫磺以两种结晶状态和一种无定形的形式存在。斜方硫是通过适当的溶液结晶得到的,如二硫化碳,,它的熔点是112℃。单斜硫由冷却熔化的硫形成,它 的熔点是119℃。两种结晶硫都融化成S -γ,由S8分子组成。S8分子呈褶皱环状,耐热高达160℃,高于160℃时,S8环断开,而这些碎片相互结合形成一个无 规则 编码规则下载淘宝规则下载天猫规则下载麻将竞赛规则pdf麻将竞赛规则pdf 形状、有高度粘稠的混合物。在较高的温度范围内,液态硫变得非常粘稠,不能从容器中倒出,颜色也从在熔点时的麦黄色变为红褐色,因为它变得更加粘稠。 As4 the boiling point of 444 °C is approached, the large-coiled molecules of sulfur are partially degraded and the liquid sulfur decreases in viscosity. If the hot liquid sulfur is quenched by pouring it into cold water, the amorphous form of sulfur is produced. The structure of amorphous sulfur consists of large-coiled helices with eight sulfur atoms to each turn of the helix; the overall nature of amorphous sulfur is described as3 rubbery because it stretches much like ordinary rubber. In a few hours the amorphous sulfur reverts to small rhombic crystals and its rubbery property disappears. 接近沸点444℃时,大盘绕分子形状的硫逐渐降解,液体硫粘度降低。如果将热的液态硫倒入冷水中骤冷,就会形成无定形硫。无定形硫的结构由八个硫原子组成大螺旋盘绕,自然界中一切无定形硫被描述为橡胶状是因为它很像普通橡胶的延伸。在几个小时内的无定形硫又还原为斜方的晶体硫,其橡胶性消失。 Sulfur, an important raw material in industrial chemistry, occurs as the free element, as SO2 in volcanic regions, as H2S in mineral waters, and in a variety of sulfide ores such as iron pyrite FeS2, zinc blende ZnS, galena PbS and such, and in common formations of gypsum CaSO4 ?2H2O, anhydrite CaSO4, and barytes BaSO4 ?2H2O. Sulfur, in one form or another, is used in large quantities for making sulfuric acid, fertilizers, insecticides, and paper. 硫,化学工业的重要原料,像自由元素那样出现,如在火山地区的二氧化硫,矿物质水中的硫化氢,和各种硫化矿石,如黄铁矿FeS2,闪锌矿硫化锌,方铅矿PbS等,通常形成石膏CaSO4 ?2H2O,无水石膏CaSO4,重晶石硫酸钡?2H2O。硫,在一种或另一种形式上,常被用于制造硫酸,肥料,杀虫剂,和纸。 Sulfur in the form of SO2 obtained in the roasting of sulfide ores is recovered and converted to sulfuric acid, although in previous years much of this SO2 was discarded through exceptionally tall smokestacks. Fortunately, it is now economically favorable to recover these gases, thus greatly reducing this type of atmospheric pollution. A typical roasting reaction involves the change: 二氧化硫中的硫在硫化物矿石焙烧中恢复和转化为硫酸,虽然前几年许多二氧化硫通过特殊的高烟囱被丢弃。幸运的是,现在经济有利收回这些气体,从而大大减少这种类型的大气污染。一个典型的焙烧反应涉及的变化:2ZnS+3 O2 – 2ZnO+ 2SO2 Phosphorus, below 800℃consists of tetratomic molecules, P4. Its molecular structure provides for a covalence of three, as may be expected from the three unpaired p electrons in its atomic structure, and each atom is attached to three others6. Instead of a strictly orthogonal orientation, with the three bonds 90°to each other, the bond angles are only 60°. This supposedly strained structure is stabilized by the mutual interaction of the four atoms (each atom is bonded to the other three), but it is chemically the most active form o f phosphorus. This form of phosphorus, the white modification, is spontaneously combustible in air. When heated to 260°C it changes to red phosphorus, whose structure is obscure. Red phosphorus is stable in air but, like all forms of phosphorus, it should be handled carefully because of its tendency to migrate to the bones when ingested, resulting in serious physiological damage. 磷,在800℃以下由四原子分子组成P4。它的分子结构提供了三个共价键,可在其原子结构从三个未成对的p电子预计,每个原子连接到另外三个。取代完全正交方向,与三方互为90 °,其键角只有60 °。据称变形力结构是由四个稳定的原子(每个原子的其他三个保税)的相互作用,但它是化学最活跃的磷形式。这种形式的磷,白色的变体,是在空气中自燃。当加热到260 °C,它转变为红磷,其结构是不清楚的。红磷在空气中稳定,但是,像所有形式的磷,它应小心操作,因为吃下去之后会进入到骨头,造成严重的生理损伤。Elemental carbon exists in one of two crystalline structures —diamond and graphite. The diamond structure, based on tetrahedral bonding of hybridized sp3 orbitals, is encountered among Group IV elements. We may expect that as the bond length increases, the hardness of the diamond-type crystal decreases. Although the tetrahedral structure persists among the elements in this group —carbon, silicon, germanium, and gray tin —the interatomic distances increase from 1.54 A for carbon to 2.80 A for gray tin. Consequently . the bond strengths among the four elements range from very strong to quite weak. In fact, gray tin is so soft that it exists in the form of microcrystals or merely as a powder. Typical of the Group IV diamond-type crystalline elements, it is a nonconductor and shows other nonmetallic properties7. 碳元素在两种晶体结构——金刚石和石墨中存在。钻石结构是根据四面体的SP3杂交轨道结合,是在第四族元素中遇到的。我们可以猜想,随着键长的增大,钻石型晶体的硬度下降。虽然四面体结构在这些族元素中存在——碳,硅,锗,灰锡——原子间的距离从碳的1.54增加为碳灰锡的2.80。因此,四个要素之间的键作用力范围从非常强的相当薄弱。事实上,灰锡是那么柔软,它在微晶形式存在,或仅仅作为一种粉末。第四主族钻石型结晶元素的典型,它是一个绝缘体,并显示其他非金属性质。