Structural formulae inorganic compounds

The first two examples in Figure 1.20 illustrate that the structural formulas of alkyl and aromatic phosphine compounds may be derived by substituting organic groups for the H atoms in phosphine (PH3), the hydride of phosphorus, discussed as a toxic inorganic compound in Section 12.10. Methylphosphine is a colorless, reactive gas. Crystalline, solid triphenylphosphine has a low reactivity and moderate toxicity when inhaled or ingested. 

It will not be denied that the properties of substances are independent of the names assigned to them. Nevertheless, the student who wishes to use the chemical literature and eventually also to contribute to it must be able to name the compounds he discusses and to visualize the structure of a compound named by someone else. A number of workers (including the present author) feel that chemical writing would benefit if formulae were substituted for names for many inorganic compounds since in most cases (but not alt) formulae are clearer, require considerably less space, and are not subject to error when a translation is attempted. However, in many books and in the majority of the important chemical journals today, compounds are generally referred to by name rather than by formula. 

Although these molecules, as a whole, are not symmetric, some of their component parts may be symmetrical. They possess what is called local symmetry. Similar atomic groups in different molecules often have similar geometries, and thus similar local symmetries. The structural formulae reveal considerable information about these local symmetries, or at least their similarities and differences in various molecules. The above simplified structural formulae are especially useful in this respect. This approach is widely applicable in organic chemistry, where relatively few kinds of atoms build an enormous number of different molecules. A far greater diversity of structural peculiarities is characteristic for inorganic compounds. 

So far, we have identified coordination compounds only by their chemical formulas, but names are also useful for many purposes. Some substances were named before their structures were known. Thus, K3[Fe(CN)g] was called potassium fer-ricyanide, and K4[Fe(CN)g] was potassium ferrocyanide [these are complexes of Fe (ferric) and Fe (ferrous) ions, respectively]. These older names are still used conversationally but systematic names are preferred to avoid ambiguity. The definitive source for the naming of inorganic compounds is Nomenclature of Inorganic Chemistry-IUPAC Recommendations 2005 (N. G. Connelly and T. Damhus, Sr., Eds. Royal Society of Chemistry, 2005). 

Synonyms Arsenic hydride Arsenic trihydride Arsenous hydride Hydrogen arsenide Chemical/Pharmaceutical/Other Class Inorganic compounds Chemical Formula AsHs Chemical Structure ... 

Organic (carbon-based) compounds are often much more complex than inorganic compounds, so it is more difficult to deduce their structures ftom their chemical formulas. Moreover, many organic formulas represent two or more isomers, each with a Lewis structure of its own (Section 12.2). The formula C6H14O, for example, has numerous isomers, including... 

STRUCTURES OF ELEMENTS AND INORGANIC COMPOUNDS Compounds are Arranged in Alphabetical Order by their Chemical Formulas (Lengths in A and Angles in Degrees)... 

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