Notational systems

The major significance of chemical nomenclature or notation systems is that they denote compounds in order to reproduce and transfer them from one coding to another, according to the intended application. As each coding may not include all the pieces of information in the other coding, or may have interpre table coding rules, the transformation is not always unambiguous and unique. 

For any sizeable system the Slater determinant can be tedious to write out, let alone the equivalent full orbital expansion, and so it is common to use a shorthand notation. Various notation systems have been devised. In one system the terms along the diagonal of the matrix are written as a single-row determinant. For the 3x3 determinant we therefore have ... 

Isomeric alkenes may be either constitutional isomers or stereoisomers There is a sizable barrier to rotation about a carbon-carbon double bond which corresponds to the energy required to break the rr component of the double bond Stereoisomeric alkenes are configurationally stable under normal conditions The configurations of stereoisomeric alkenes are described according to two notational systems One system adds the prefix CIS to the name of the alkene when similar substituents are on the same side of the double bond and the prefix trans when they are on opposite sides The other ranks substituents according to a system of rules based on atomic number The prefix Z is used for alkenes that have higher ranked substituents on the same side of the double bond the prefix E is used when higher ranked substituents are on opposite sides... 

Absolute Configuration According to the Cahn-Ingold-Prelog Notational System... 

The role of nitronium ion in the nitration of benzene was demonstrated by Sir Christo pher Ingold—the same per son who suggested the SnI and Sn2 mechanisms of nu cleophilic substitution and who collaborated with Cahn and Prelog on the R and S notational system... 

Glycine is the simplest ammo acid and the only one m Table 27 1 that is achiral The a carbon atom is a chirality center m all the others Configurations m ammo acids are normally specified by the d l notational system All the chiral ammo acids obtained from proteins have the l configuration at their a carbon atom meaning that the amine group IS at the left when a Fischer projection is arranged so the carboxyl group is at the top... 

Thompson, T.E., Grauke, L.J., and Young, E., Pecan kernel color standards using the Munsell color notation system, J. Am. Soc. Hort. ScL, 121, 548, 1996. 

As usual, Feynman was right. His little particles captures an essential fact about atoms. They are tiny—so tiny that a teaspoon of water contains about 500,000,000,000,000,000,000,000 of them. Handling numbers this big is awkward. Try dividing it by 63, for example. To accommodate the very large numbers encountered in counting atoms and the very small ones needed to measure them, chemists use the scientific notation system. 

First, by indulging his passionate belief in science for the people, he gave students the kind of hands-on education in chemistry that he had wanted as a young man. Before Frankland, students everywhere learned science from books most never even entered a laboratory. Working tirelessly over a period of 15 years, Frankland gradually changed that and dramatically improved the state of science education in Britain. He compiled a list of 109 experiments that students needed to understand firsthand in order to pass his examinations. He wrote a textbook that became a standard for chemistry instruction, in part because it incorporated his ideas on valency and organic structures and his newly developed notation system. 

In colorimetric terms, color differences are generally characterized by the distance between two colors in one of the color notation systems, most commonly the CIELAB system. The difference determined in this way represents the total color difference. Since a color is characterized by three quantities, a color difference can also be expressed in terms of three difference components (that is, differences in the color coordinates) and thus described in greater detail. Visually equal color differences between almost equal colors may, upon colorimetric measurement, be considered distinct if the colors of one pair differ strongly from those of the other pair. The formulas for color differences are further elaborated in order to remedy this defect. 

Dyson notation org chem A notation system for representing organic chemicals developed byG. Malcolm Dyson the compound is described on a single line, symbols are used for the chemical elements involved as well as for the functional groups and various ring systems for example, methyl alcohol is C.Q and phenol is B6.Q. dT-son no.ta-shon ... 

Figure 5.11 A more intricate model of a higher-dimensional object. [For more details on this shape, see Ryan, R (1991) The earthscore notational system for orchestrating perceptual consensus about the natural world. Leonardo. 24(4) 457-65. The drawing was done by Gary Allen. The bottle object is called a relational circuit.]...

SMILES (Simplified Molecular Input Line Entry Systems) is a line notation system based on principles of molecular graph theory for entering and representing molecules and reactions in computer (10-13). It uses a set of simple specification rules to derive a SMILES string for a given molecular structure (or more precisely, a molecular graph). A simplified set of rules is as follows ... 

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