Compositional nomenclature elements

NE OF THE CENTRAL THEMES of this book is to show how the development of the concept of neutral salt in the eighteenth century made possible the creation of a compositional nomenclature by L.-B. Guyton de Morveau in 1782, which when adapted to the new chemistry of Lavoisier led to the creation of a definition of simple body the material element. The second major theme then describes how this new chemistry led to the final development of modern chemical composition in its atomic structure introduced by John Dalton. His atomic theory contained the symbolic operators that furnished the most convenient representation of the material composition of bodies that had become available by the end of the eighteenth century. The idea of an individual atomic weight unique to each element depended most immediately upon the concept of simple body, introduced by the authors of the M thode de nomenclature chimique in 1787. The new nomenclature was itself based on the principle that a name of a body ought to correspond to its composition. 

Woolley AR, Kempe DRC (1989) Carbonatites nomenclature, average chemical composition and element distribution. In Bell K (ed) Carbonatites. Genesis and Evolution. Unwin-Hyman, Boston pp 1-14 Wortel MJR, Spakman W (2000) Subduction and slab detachment in the Mediterranean-Carpathian region. Science 290 1910-1917 Wyllie PJ, Tuttle OF (1960) The system Ca0-C02-H20 and the origin of carbonatites. J Petrol 1 1-46... 

IR-1.5.3.2 Compositional nomenclature IR-1.5.3.3 Substitutive nomenclature IR-1.5.3.4 Additive nomenclature IR-1.5.3.5 General naming procedures IR-1.6 Changes to previous IUPAC recommendations IR-1.6.1 Names of cations IR-1.6.2 Names of anions IR-1.6.3 The element sequence of Table VI IR-1.6.4 Names of anionic ligands in (formal) coordination entities IR-1.6.5 Formulae for (formal) coordination entities IR-1.6.6 Additive names of polynuclear entities IR-1.6.7 Names of inorganic acids IR-1.6.8 Addition compounds IR-1.6.9 Miscellaneous... 

In the days of alchemy and the phlogiston theory, no system of nomenclature that would be considered logical ia the 1990s was possible. Names were not based on composition, but on historical association, eg, Glauber s salt for sodium sulfate decahydrate and Epsom salt for magnesium sulfate physical characteristics, eg, spirit of wiae for ethanol, oil of vitriol for sulfuric acid, butter of antimony for antimony trichloride, Hver of sulfur for potassium sulfide, and cream of tartar for potassium hydrogen tartrate or physiological behavior, eg, caustic soda for sodium hydroxide. Some of these common or trivial names persist, especially ia the nonchemical Hterature. Such names were a necessity at the time they were iatroduced because the concept of molecular stmcture had not been developed, and even elemental composition was incomplete or iadeterminate for many substances. 

Elemental composition, ionic charge, and oxidation state are the dominant considerations in inorganic nomenclature. Coimectivity, ie, which atoms are linked by bonds to which other atoms, has not generally been considered to be important, and indeed, in some types of compounds, such as cluster compounds, it caimot be appHed unambiguously. However, when it is necessary to indicate coimectivity, itaUcized symbols for the connected atoms are used, as in trioxodinitrate(A/,A/), O2N—NO . The nomenclature that has been presented appHes to isolated molecules (or ions). Eor substances in the soHd state, which may have more than one crystal stmcture, with individual connectivities, two devices are used. The name of a mineral that exemplifies a particular crystal stmcture, eg, mtile or perovskite, may be appended. Alternatively, the crystal stmcture symmetry, eg, rhombic or triclinic, may be cited, or the stmcture may be stated in a phrase, eg, face-centered cubic. 

Over the past two decades, the pharmaceutical community has become acutely aware that many substances of interest can be obtained in more than one crystal form, and that the properties of these solids may often be quite different. Polymorphism is the term used to denote crystal systems where a substance can exist in different crystal packing arrangements, but all of which are characterized by exactly the same elemental composition. Other crystal variations are known where a given substance exists in different crystal packing arrangements, but each of which exhibits a different elemental composition. Since this latter phenomenon usually involves the inclusion of one or more solvent molecules in the crystal, the term solvatomorphism has been coined to replace the inconsistent nomenclature used over the years. These and related phenomena have been the focus of several recent monographs [1-3],... 

The simplest kind of formula is a compositional formula or empirical formula, which lists the constituent elements in the atomic proportions in which they are present in the compound. For such a formula to be useful in lists or indexes, an order of citation of symbols (hierarchy) must be agreed. Such hierarchies, often designated seniorities or priorities, are commonly used in nomenclature. For lists and indexes, the order is now generally recommended to be the alphabetical order of symbols, with one very important exception. Because carbon and hydrogen are always present in organic compounds, C is always cited first, H second and then the rest, in alphabetical order. In non-carbon-containing compounds, strict alphabetical order is adhered to. 

Specialists in nomenclature recognise two different categories of nomenclature. Names that are arbitrary (including the names of the elements, such as sodium and hydrogen) as well as laboratory shorthand names (such as diphos and LithAl) are termed trivial names. This is not a pejorative or dismissive term. Trivial nomenclature contrasts with systematic nomenclature, which is an assembly of rules, themselves arbitrary. The function of specialists in nomenclature is to codify such rules so that everyone can use them to identify pure substances, rather like many of us use an alphabet to represent words. There may be more than one way to name a compound or species, and no one way may be superior to all the others. Names also vary in complexity, depending upon how much information needs to be conveyed. For example, a compositional name conveys less information than a structural (or constitutional) name, because this includes information about the arrangement of atoms in space. 

It is unfortunate that Keir did not push on with this idea of an element as any body that we have not yet been able to decompose. As we shall see later, this is precisely the definition that comes to be utilized by many later chemists, and constitutes the operational basis for the new nomenclature and ultimately the expression of composition in terms of atomic weights. I know of no earlier advocacy of this idea so clearly stated as this by James Keir. 

The brilliant Frenchman s legacy will be with us forever. Traite Elementaire de Chimie was the world s first real chemistry text. In it Lavoisier introduced a whole new system of nomenclature, which we still use. No longer would chemists refer to oil of vitriol or flowers of zinc. Instead they adopted names like sulfuric acid and zinc oxide, names that reflected the actual composition of the substances in question. Lavoisier clearly defined elements as substances that could not be broken down further by chemical means. Chemistry was evolving into an organized science ... 

The above is a typical illustration of many confused notions of the ancients due to the fact that they possessed no knowledge of the elementary constituents of substances. The criteria for classification and nomenclature were based upon superficial phenomena, or upon the sources or the applicability of the substances to particular purposes. So long as the. concept prevailed that all substances consisted of variable quantities of the four Aristotelian elements, and that their properties were determined by the proportion of these elements, it was not possible for them to conceive of the possibility of a method of analysis based upon elementary compositions of bodies as understood in modern times. 

Inorganic additive nomenclature, however, names both simple and complex entities of more than 100 elements. Inorganic nomenclature also provides several degrees of complexity in order to enable a name for a compound to indicate empirical composition, molecular composition, composition and connectivity, and complete qualitative three-dimensional compound structure. 

Additive nomenclature1 is based on the combination of element names or roots of element names and/or ligand names. The simplest and oldest additive nomenclature is binary nomenclature that expresses two components, e.g. sodium chloride. The cationic or electropositive portion of the compound expressed in a binary name is the element name unchanged or a group name ending in -ium , and the anionic or electronegative portion of a compound expressed in the name ends in -ide, -ite or -ate. The proportions of cations and anions in neutral compounds are indicated by Stock numbers or simple or multiplicative prefixes (see Section 3.3.2). Additive nomenclature denotes composition. For examples see Table 1. 

Many compounds were given informal, common names before their compositions were known. Common names include water, salt, sugar, ammonia, and quartz. A systematic name, on the other hand, reveals which elements are present and, in some cases, how the atoms are arranged. The systematic naming of compounds, which is called chemical nomenclature, follows a set of rules, so that the name of each compound need not be memorized, only the rules. 

In spite of the complexity of the system, elemental sulfur and its incurable, confused nomenclature—literally almost the whole Greek alphabet has been misused to denote mixtures of largely unknown composition —there is one very important fact in this system. It is the fact that... 

Binary type nomenclature. In this system, the composition of a substance is specified by the juxtaposiliun of element group names, modified or unmodified, together with appropriate numerical prefixes, if considered necessary,... 

The systematic naming of an inorganic substance involves the construction of a name from entities which are manipulated in accordance with defined procedures to provide compositional and structural information. The element names (or roots derived from them or from their Latin equivalents) (Tables I and II, see also Chapter IR-3) are combined with affixes in order to construct systematic names by procedures which are called systems of nomenclature. 

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