化学化工专业英语 课文翻译 第八课8.2

8 . 2 introduction

Mastering chemical nomenclature is little different from learning a new language, such as German . In order to understand the German scientific literature , you must , e . g , learn that the compound H2 is called Wasserstoff .English-speaking chemists call it hydrogen . Y our task now is to memorize the names of enough compounds and become sufficiently familiar with the several systems of naming compounds that chemistry ceases to be a " foreign language .

The first thing to learn about naming chemical compounds is that there is usually more than one way to do it . We begin with the simplest system , in which a trivial name , 1 . e . , one that has no sensible origin , is assigned to a compound .Some examples are

Some names , such as quicklime for CaO , derive from the origin of the compound in this case , limestone , CaCO3 Such word origins are often remembered only by etymologists , but the names have persisted for so long that they are an established part of the language . Can you imagine anyone seriously asking for a drink of dihydrogen oxide ? The word water serves the purpose much better .

As we come to less common and more complex compounds , the use of trivial names gives way to a more systematic approach．If there are only two elements in the compound , it is customary to name the more metallic element first and the less metallic , or more electronegative , element second , with the suffix “- ide , , . Some examples are

For compounds containing still only two elements but more than two atoms , the pre fixes " mono -，, , " di -”, " tri 一，, etc , become necessary . Some examples of such compounds are the oxides of nitrogen . Another such series is that of the oxide of chlorine .Because chlorine , like nitrogen , is slightly less electronegative than oxygen , the word chlorine cornes first

if no confusion can result , the prefixes " mono , , and “di -, are sometimes dropped .

A class of compounds in which such prefixes are seldom used is that in which the metal atom usually exhibits only one oxidation state Depending on the oxidation state of the other element , the number of anions per cation is then fixed . Some examples are

The next level of complexity in naming Inorganic compounds arises when there are three elements present . V ery often , one of these elements is oxygen . Such compounds are named by combining the suffix “ ate “ , with the name of the less electronegative of the two nonmetallic elements. For example , NaNo3 is sodium nitrate . The problem with this is that there is a similar compound with nitrogen in the + 3 oxidation state , NaNO2. such compounds with the element in a lower oxidation state use the suffix “-ite , , , so NaNO2 is sodium nitrite . But the number of chemical compounds is not bounded by the chemists ' vocabulary , and there are several such examples entailing more than two oxidation states .To solve this problem , the prefix ' ' hy - po 一，, ( meaning " below , , ) is used in the name of the compound In which the less electronegative element is in the lowest oxidation state , and the prefix " per-，, ( meaning " highest , , ) is used

when it is in the highest oxidation state Some examples of the use of this system are shown In the following table ( Table 8 . 2 )

In the inorganic acids , the suffixes “-ous , , and "- ic , , are used to denote the lower and higher oxidation states , respectively These same suffixes are also used with the names of a number of metals , namely , those that usually exhibit more than one oxidation state Some examples are cobaltous and cobaltic , and mercurous and mercuric . The nomenclature is complicated slightly by the fact that , for a few such metals , these terms are derived from the Latin name of the element rather than the English name .

All but eleven of the elements are given a symbol corresponding to one or two letters In the English name of the compound ( The first letter is always capitalized and the second letter 15 never capitalized ) One of these exceptions is tungsten , whose symbol ( W ) is derived from the German name of the element , Wolfram The other ten have symbols derived from their Latin names . These are , stibium ( Sb ) for antimony , cuprum ( Cu ）for copper , aurum ( Au ) for gold ，ferrum ( Fe ) for iron , plumbum ( Pb ) for lead , hydrargyrum ( Hg ) for mercury , kalium ( K ) for potassium , argentum ( Ag ) for silver , natrium ( Na ) for sodium , and stannum ( Sn ) for tin. The use of the suffixes ' ’- ous , , and “-ic , , with three of these metals 15 illustrated below

The system works well as long as there are only two major oxidation states of the metal atom , as in those examples .

The most rational and selfconsistent system of nomenclature of inorganic compounds is that adopted in 1957 by the ultimate authority in such matters , the International Union of Pure and Applied Chemistry. these rules , popularly called the IUPAC Rules , are the model for chemists throughout the world to follow , and are becoming ever more dominant In the chemical literature . Note that the oxidation state of the metal atom is specified by a Roman numeral whenever there could be some doubt about it , but not otherwise Let us see how the examples shown above are named according to this system

掌握化学命名是学习新的语言，如德国略有不同。为了解德国科学文献，你必须要e。g、学习复合H2 称为Wasserstoff。讲英语的化学家称之为氢。现在你的任务是要记住足够化合物的名字和充分熟悉的几个系统命名化合物的化学不再是"外国语言。

首先要了解命名的化合物是通常有不止一种方法来做这件事。我们开始用最简单的系统，在其中一个平凡的名字，1。(e)。那有没有明智的起源，分配给一种化合物。下面是一些示例

一些名称，例如，为曹、生石灰得出从这种情况下，灰岩中的化合物的起源，这种词语来源往往只能由词源，但名字记住的CaCO3 有持续这么久他们是既定的语言的一部分。你可

以想象有人认真询问二氢氧化的喝一杯吗？字水目的好得多。

我们来到不太常见和更复杂的化合物，平凡名称的使用让位于更有系统的做法，如果在大院里只有两个元素，这是习惯来命名，更金属元素第一和不少金属，或更负电元素第二，与后缀"-ide、、。下面是一些示例

含仍只有两个元素，但超过两个原子，pre 化合物修复了"单声道，、、"迪-""，三一，等，成为必要。这种化合物的一些示例是氮氧化物。另一种系列是氧化物的氯。因为氯、氮，像是略低于负电氧气，word 氯科恩斯比第一次

没有混淆会导致的f、前缀"单声道、、和"di-，有时会下降。

一类化合物很少使用这样的前缀的是在其中金属原子通常展品只有一个氧化状态取决每阳离子阴离子的数量的其他元素的氧化状态被然后固定。下面是一些示例

当有三个要素目前出现命名的无机化合物中的复杂性的下一级。很多时候，这些元素之一是氧气。通过结合后缀"吃"命名的这种化合物的不少负电两个非金属元素的名称。例如，NaNo3 是硝酸钠。这个问题是类似化合物与氮素+ NaNO2 3 氧化状态。这种化合物与低氧化状态中的元素使用后缀"-ite、、、所以NaNO2 是亚硝酸钠。但化学化合物的数量不受化学家的词汇，并有几个这种例子涉及两个以上的氧化国家。若要解决此问题，该前缀'' hy-大埔一，，（指"低于、、）少负电元素是，最低氧化状态和（即"最高、、）（表8 下表中显示了一些示例使用此系统的最高氧化状态时使用前缀"每、，复合名称中使用.2）

无机酸的后缀"-ou、、和"-ic、是用来表示较低和高氧化国家、分别这些相同的后缀也可用于一系列金属的名称，即那些通常表现出多个氧化状态是钴及钴盐，和汞和汞的一些示例。名词术语是稍微复杂的是，对于几种金属，这些术语都源自拉丁文的元素的名称，而不是英文名称

除了十一的元素的所有得到相应的复合的英文名称中的一个或两个字母的符号（首字母总是以大写形式和第二个字母15 从来没有大写）这些例外之一是的钨、其符号(W) 来自德国的元素，Wolfram 其他十个有源自拉丁文的符号名称。这些都是锑（某人）的锑、铜(Cu）for 铜、金（非盟）的黄金，ferrum (Fe) 为铁、铅、汞、钾(K) 的钾、钠、和锡(Sn) 钠(Na) 银有价(银) 汞(Hg) 铅(Pb)。使用后缀的'-ou、、和"-ic、与三个金属15 如下所示

系统工作以及存在是只有两种主要氧化状态的金属原子，如这些示例所示。

无机化合物的最合理和自我一致制度是术语的1957 年通过的最终权力在这种事情，国际工会的理论和应用化学。这些规则，俗称IUPAC 规则，为在整个世界和是化学家模型越来越越来越主流化学文献中。注意金属原子的氧化状态指定由罗马数字，每当可能有一些疑问，但不是以其他方式让我们看到如上所示的示例根据这项制度的命名方式