Binary compounds, nomenclature

A remarkable variety of compounds in the Ca-(B,C,N) system has opened a window for research in related fields. With the elements boron, carbon and nitrogen, substance classes such as borocarbides, boronitrides, and carbonitrides can be considered to contain anionic derivatives of binary compounds B4C, BN, and C3N4. Until now, most compounds in these substance classes have been considered to contain alkali, alkaline-earth, or lanthanide elements. Lanthanide borocarbides are known from the work of Bauer [1]. Lanthanide boronitrides represent a younger family of compounds, also assigned as nitridoborates [2] following the nomenclature of oxoborates. 

None of these compounds contains a metallic element, so we apply the guidelines for binary compound nomenclature. 

Some compounds, namely molecular compounds, contain only nonmetals. Normally the compounds you need to name are binary compounds (containing only two elements). If you have highlighted the metalloids on your periodic table, everything to the right of the metalloids is a nonmetal. The following rules apply to both nonmetals and metalloids. The only nonmetal excluded from these nomenclature rules is hydrogen. 

Although the general term carbide applies to the binary compounds of the element carbon, this term is used in systematic nomenclature only when carbon is the more electronegative of the two elements involved. Thus, C02 is called carbon dioxide and not oxygen carbide since oxygen is more electronegative than carbon. Although carbon forms binary compounds with most of the nonmetals, metalloids, and metals, only a few of the more common members of this class are considered here. 

Nomenclature of Salts. — Salts containing only two elements follow the rule for binary compounds, aiid hence end in -ide. This suffix is added to an abbreviated form of the name of the non-metal, e.g. chloride, bromide, duor-ide, etc. Notice that the prefix hydro- is omitted, and that the name of the metal precedes, c.g. sodium chloride, potassium bromide, calcium fluoride, etc. It will soon be shown experimentally that salts may be regarded as derived from... 

However, more was involved than was given in those simple statements. Werner was not satisfied with the inorganic nomenclature practices of his time for even binary compounds and had earlier adopted a series of suffixes (or infixes) to indicate valence (34) ... 

Inverted forms of the chemical names (parent index headings) are used for most entries in the alphabetically ordered index. Organic names are listed at the parent based on Rule C-10, Nomenclature of Organic Chemistry, 1979 Edition. Coordination compounds, salts and ions are listed once at each metal or central atom parent index heading. Simple salts and binary compounds are entered in the usual uninverted way, e.g.. Sulfur oxide (SxO), Lira-nium( V) chloride (UCL). 

When atomic theory developed to the point where it was possible to write specific formulae for the various oxides and other binary compounds, names reflecting composition more or less accurately then became common no names reflecting the composition of the oxosalts were ever adopted, however. As the number of inorganic compounds rapidly grew, the essential pattern of nomenclature was little altered until near the end of the 19th century. As a need arose, a name was proposed and nomenclature grew by accretion rather than by systematization. 

Chemical nomenclature deals with names of elements and their combinations. Whereas writing the symbol or the name of an element is straightforward, a choice of which element to write first in the formula and in the name has to be made as soon as an element is associated with one or more other elements to form, for example, a binary compound. The order of citation of elements in formulae and names is based upon the methods outlined below. Furthermore, groups of atoms, such as ions, ligands in coordination compounds and substituent groups in derivatives of parent hydrides, are ordered according to specified rules. 

Since this is the book s first look at nomenclature, we limit ourselves to molecular binary compounds, those made up of only two elements, both nonmetals. Other binary compounds are named in Chapter 4, after you learn more about ions. Let s start by naming four molecular binary compounds to get an idea how names are formed, and then follow this with some rules. 

Many ionic componnds are binary compounds, or compounds formed from just two elements. For binary componnds the first element named is the metal cation, followed by the nonmetallic anion. Thus NaCl is sodium chloride. The anion is named by taking the first part of the element name (chlorine) and adding -ide. Potassium bromide (KBr), zinc iodide (Znl2), and aluminum oxide (AI2O3) are also binary componnds. Table 2.2 shows the -ide nomenclature of some common monatomic anions according to their positions in the periodic table. 

The first nomenclature for inorganic structure types has been proposed by Ewald Hermann in 1931. They used letters to designate the kind of chemical compound and numerals to distinguish among compounds with the same general formula. The chemical elements are designated by the letter A, the binary compounds by the letter B, the AB2 compounds by C and so on. Examples are A1 for Cu, A10 for Hg, B1 for NaCI, B3 for ZnS (sphalerite), HI2 for Mg2Si04 (olivine), G1 for CaCOa (calcite). This notation has not received much acceptance, possibly due to its lack of self explanatory structural information. 

During Werner s time compositional nomenclature for binary compounds had already been agreed upon in much the same way as today, and names such as manganese dichloride and manganese monooxide were in common use to express information about stoichiometric compositions only. For complex compounds, this type of nomenclature had simply b n extended as in the notational example 3 KCN,Fe(CN)3. Werner realized that diis notation could be modified to became a nomenclature including structural information, when this was available, and potassium hexacyanoferriate is his ingenious proposal (2). This is an example of what is today referred to as additive nomenclature or coordination nomenclature, as opposed to the substitutional nomenclature of organic chemistry. 

The name of a BINARY COMPOUND, a compound composed of two elements, is usually derived from the names of the elements (see back cover) usually, the metallic or electropositive element is written first and the second element is given the suffix -ide. There are four systems of nomenclature ... 

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