Simple names

Simple ethers derive their name from the two groups attached to the oxygen followed by the word ether, eg, diethyl ether, CH3CH2OCH2CH3. Eor symmetrical ethers the "di" prefix is often omitted. If one group has no simple name, the compound may be named as an alkoxy derivative, eg, 2-ethoxyethanol, CH3CH2OCH2CH2OH. 

Completely trivial names continue in use for good reasons, of which an important one is the need for a simple name for frequent communication concerning a commonly encountered compound or structure. For obscure compounds there is surely neither need nor desirability to perpetuate trivial names, and coining new trivial names is almost never justified. Let us, however, consider purine , the trivial name for what might more systematically be named imidazo[5,4-ring system is so important in biochemistry that exclusive use of one of the systematic names would be intolerable. If the name purine were not available, another short trivial name would inevitably be coined, or even an acronym ( IP or TAP ). It is better to retain the name sanctioned by roughly a century of use, and benefit from a link in comprehension with the past. 

The need for simple names to describe complex structures has been met in several ways, the most straightforward of which is to use a trivial name giving little or no structural information e.g. morphine, opuntiol). Such names are.often based on the Latin name of the species from which the compound was isolated e.g. opuntiol from Opuntia eliator). While this is acceptable for a newly isolated compound of unknown structure, it is less satisfactory once the structure is established. What is needed is some means of establishing the relationship of the compound to others in the same class, without going into too much detail with regard to structure and stereochemistry. This can be achieved by defining, for a particular group of structures, a parent structure. 

Most German simple names of organic acids are correctly translated by... 

Since singular points are identified with the positions of equilibria, the significance of the three principal singular points is very simple, namely the node characterizes an aperiodically damped motion, the focus, an oscillatory damped motion, and the saddle point, an essentially unstable motion occurring, for instance, in the neighborhood of the upper (unstable) equilibrium position of the pendulum. 

Those organic compounds that contain a hydroxyl group (-OH) are called alcohols and follow the simple naming procedure. 

One of the significant innovations in control of pressure oscillations and supersonic mixing enhancement has been very simple, namely using nonaxisym-metric nozzles. Simple triangular, square, rectangular, and elliptic nozzles have been shown to effectively decrease combustion pressure oscillations, as well as increase supersonic mixing [7]. 

Figure 9-1 shows the carbonyl group. Note This name isn t part of the formal nomenclature of organic compounds, but just a simple name for a commonly seen group. 

For larger aggregations, a set of structural descriptors (see Table 4.7) is used. Homonuclear entities can have relatively simple names using these descriptors. The examples below give an indication of how names are arrived at. For more complex cases, the reader is referred to the Nomenclature of Inorganic Chemistry, p. 192. All the devices already discussed above can be called into use as necessary. 

Gas-Holder.—The next subject for consideration is the gas-holders, or vessels in which the gas is stored ready for delivery into the mains, which distribute it throughout the districts to be lighted. These vessels were originally termed gasometers, which name is even sometimes now applied to them but as they have nothing whatever to do with the measurement of gas, but are merely vessels of capacity, the simple name of gas-holder appears more expressive and appropriate. 

Typically, reactants and products are represented by their atomic or molecular formulas, but molecular structures or simple names may be used instead. Phases are also often shown (s) for solid, ( ) for liquid, and (g) for gas. Compounds dissolved in water are designated (aq) for aqueous. Lastly, numbers are placed in front of the reactants or products to show the ratio in which they either combine or form. These numbers are called coefficients, and they represent numbers of individual atoms and molecules. For instance, to represent the chemical reaction in which coal (solid carbon) burns in the presence of oxygen to form gaseous carbon dioxide, we write the chemical equation... 

Leak testing can also be done using radiotracers. Here the basic idea is simple— namely, to inject radiotracer into a pipe, flask, or whatever is suspected to be leaking and look for activity that appears outside the container. Suitable caution must be exercised, of course, to be sure that the leaked radioactivity is not a hazard. 

Development, on the basis of the names of the larger parent compounds and the nor- structures and with the aid of established nomenclature rules, of logical series of simple names which are sufficiently definitive to show immediately the relations among compounds of a single... 

Some elements such as gold and silver have simple names, but are known by their Latin abbreviations in the periodic table. The symbol for gold—Au—comes from aurum, the Latin word for gold. The Latin word for silver is argentum, which explains why its symbol in the table is Ag. 

In Eq. (62), the concentration of cations in aqueous solution is symbolized by [M+]. An assumption, explicit in Eq. (62), is that the binding equilibrium does not lead to changes in the polyion conformation [31, 65-73]. The physical content of Eq. (62) is simple, namely, that if a ligand of charge z neutralizes z charges on the polyion, then this process leads to the release of z counterions into the bulk solution [31, 65-73]. 

So far, we have talked a lot about compounds by name. Many of the names we ve used (palytoxin, muscone, brevetoxin...) are simple names given to complicated molecules without regard for the actual structure or function of the molecule—these three names, for example, are all derived from the name of the organism from which the compound was first extracted. They are known as trivial names, not because they are unimportant, but because they are used in everyday scientific conversation. 

Names like this are fine for familiar compounds that are widely used and referred to by chemists, biologists, doctors, nurses, perfumers alike. But there are over 16 million known organic compounds. They can t all have simple names, and no one would remember them if they did, For this reason, the IUPAC (International Union of Pure and Applied Chemistry) have developed systematic nomenclature, a set of rules that allows any compound to be given a unique name that can be deduced directly from its chemical structure. Conversely, a chemical structure can be deduced from its systematic name. 

A very flexible way of getting new, simple names for compounds can be to combine a bit of systematic nomenclature with trivial nomenclature. 

The root of each name (highlighted in colour) serves an important function. It tells you the number of carbon atoms in the chain. The suffix -ane tells you that these compounds are alkane hydrocarbons. Thus the root and the suffix of one of these simple names provide the complete structural story of the compound. 

A network is composed of units or simple named nodes, which represent the neuron bodies. These units are interconnected by links that act like the axons and dendrites of their biological counterparts. A particular type of interconnected neural net is shown in Fig. 5.12. In this case, it has one input layer of three units (leftmost circles), a central or hidden layer (five circles) and one output (exit) layer (rightmost) unit. This structure is designed for each particular application, so the number of the artificial neurons in each layer and the number of the central layers is not a priori fixed. 

Utilization of this principle for the synthesis of the target tree-like (dendritic) macromolecule is shown in Scheme 4.31. The basic reaction chosen was again very simple, namely the formation of benzyl ethers from phenols and benzylic halides. It was found that the coupling of benzylic bromide 91 with 2 equivalents of 3,5-dihydroxybenzyl alcohol 92 could be carried out without affecting the... 

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