Coordination Principle

Stereochemical Features of Benzene and Toluene Coordination Chemistry. Benzene forms an ordered chemisorption state on the flat Ni(lll) and Ni(100) surfaces at 20°C with unit cells of (2/3x2/3)R 30° and c(4x4), respectively (13). The symmetry data do not fix the registry of the benzene with respect to the metal atoms nor the orientation of the ring plane to the surface plane. However, basic coordination principles would suggest that the benzene ring plane should be parallel to the surface plane. In Figures 8 and 9, possible registries of the benzene with respect... 

Generally, a crystal is electrically neutral. This implies that the crystal should have an equal number of positive and negative charges. Thus, when oppositely charged ions come together to form a neutral crystal structure, each ion coordinates with as many ions of opposite charge as the size permits. This coordination principle dictates both electrical neutrality of the crystal structure and compact packing of the atoms within the structure. 

Under the extended coordination principle, the names of the attached ligands are given, in alphabetical order, in front of the name of the central metal anionic ligands are given the -o suffix. Thus Me2SnCl2 would be dichlorodimethyltin, and Me3SnSnMe3 would be hexamethylditin. 

To help with this examination, I will begin by making explicit a principle on which I believe semantic externalists rely. The coordination principle is the thesis that scientific kinds and the natural kinds recognized by natural language users line up or can be mapped onto one another one-to-one. A brief examination of an externalist picture of kind reference will show how the coordination principle is relied on. 

While the ordinary language user and even the baptizer need not have true beliefs about water in order to refer to it, someone in the community eventually will need to have these beliefs if the meaning of water is to be made exphcit. The obvious people to ask about the nature of water are chemists, and semantic externalists have often assumed that this is where we must turn. Putnam and Kripke are not very explicit about the details of the role chemists play in semantics, but this is where I believe the coordination principle is implicitly rehed upon. Chemists discover the natural kinds of the material world, which I will call chemical kinds. The coordination principle presumes that the very same kinds that chemists discover are the ones relevant to ordinary language. If this is the case, then when you describe a chemical kind in detail, you will have nailed down the semantics of the ordinary kind term associated with that chemical kind. Putnam and Kripke seem to believe that in the case of water, chemists describe a chemical kind whose members include all and only the molecules with molecular formula H2O. Appealing to this fact and to the coordination principle, they conclude that water is H2O. 

Closer examination of what water really is, I believe, shows that for chemists, water is not just the set of all molecules with molecular formula H20. There are multiple chemical kinds that might reasonably be coordinated with the ordinary language kind water. Because chemistry provides us with many different types of natural kinds, and because it does not provide us with rules favoring one set of kinds over another, deference to the findings of chemistry will not unambiguously allow us to discover the extensions of natural kind terms in ordinary language. A more nuanced version of the coordination principle, which has specific rules for picking out the appropriate chemical kind in particular circumstances, will be needed to carry forward the semantic externalist project. 

Both hydrogen and oxygen are found in a variety of isotopes in nature, giving rise to the phenomenon of isotopic isomerism. After describing how this phenomenon applies to water, I will discuss the implications of isotopic isomerism for the coordination principle. Although the presentation of the scientific and philosophical issues here is my own, I am indebted to the insights found in Mellor (1974), Stroll (1998), and Needham s (2000) discussions of these issues. 

Neither treating isomers as impurities nor treating H20 as a higher order term picking out all its isomers seems to be an acceptable way to find the single chemical kind demanded by the coordination principle. It is clear that the system of kinds recognized within chemistry is very complex and multi-faceted, which is at odds with the coordination principle s demand for a single chemical kind to be associated with... 

The discussion of isotopic isomerism is just once source of chemical complexity that poses problems for the coordination principle. Many other fascinating and complicating factors arise when we consider the macroscopic properties of water.6 These are especially important as chemists usually think of water as a macroscopic substance with macroscopic properties, not merely as a collection of water molecules. While it would be fascinating to explore these complexities further, I believe we already have enough information to reexamine the coordination principle. 

Our very brief examination of the nature of water has revealed that there is no single kind for water that is useful in all chemical contexts. In particular, we have seen that the set of substances with molecular formula H20 is often not a very usefiil chemical kind. It fails to make distinctions among substances that both chemists and ordinary language users would want to make. Even if the coordination principle is acceptable without revision, we should choose a kind with more careftdly determined membership conditions. Perhaps, we could choose a kind that takes into account standard isotopic distributions. I am skeptical that this will be an adequate solution, however, because the problems with the coordination principle run deeper then this solution addresses. 

Two results of our investigation put pressure on the coordination principle in its current form. The first result is that chemistry cannot just hand us a single kind with which we can associate the ordinary language kind water, because in chemistry there is a more complex system of kinds. The second result is that chemists often deal with these issues by using kind terms in context sensitive ways. I believe that each of these holds a key to refining the coordination principle. 

In this essay I have discussed an assumption of semantic externalist theories which I called the coordination principle. This is the idea that natural language kinds and scientific kinds line up or can be mapped onto one another one-to-one. A closer look at water shows that there is not this type of simple one-to-one match between chemical and ordinary language kinds. In fact, the use of kind terms in chemistry is often context sensitive and in cases where chemists want to ensure no ambiguity, they use a very complex and nuanced set of kind terms, none of which could be reasonably associated with the ordinary language kind term water alone. Since we cannot just turn to chemistry to find a single chemical kind that can be used to determine the extension of water, there is not any strict sense in which water is H2O, because exactly what water is depends on the context in which water is uttered. 

Part 3 Phase-to-phase insulation coordination. Principles, rules and application guide. (Superseded by Part 1, 7th edition). 

As indicated earlier, the other coordination principles involved shall be discussed in subsequent examples. 

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