Coral

The study of generalized Clar structures and their relations to the Kekule structures led to the introduction of a new concept [92] which was eventually named coral [114]. 

Three double bonds in a six-membered ring can have two distinct arrangements, A and B  

Let k ,k2,. ..,kk be the Kekule structures of a benzenoid molecule. Define a mapping f which transforms a Kekule structure k into another Kekule structure kj so that all A-type arrangements of double bonds in k are changed into arrangements of type B whereas all other double bonds are left unchanged. This will be denoted as f(k,) = kj. 

For example, f(kj) = k2 and f(k2) = k3. Furthermore, f(k3) = k3 because k3 does not have any A-type arrangements of double bonds. 

It is clear that f maps the set (kl5 k2,. ..,kk onto itself. Such a mapping can be visualized by means of a diagram. For instance, COR is the diagramatical representation of the mapping of the Kekule structures of benzoanthracene. 

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CqHqIaNOi. Pale, straw-coloured needles, m.p. 198 C. Found in certain marihe organisms, such as corals and sponges, and in the thyroid gland. 

Reservoir rocks are either of clastic or carbonate composition. The former are composed of silicates, usually sandstone, the latter of biogenetically derived detritus, such as coral or shell fragments. There are some important differences between the two rock types which affect the quality of the reservoir and its interaction with fluids which flow through them. 

PGAj derivatives can be obtained in relatively large amounts from gorgonian corals. Since PGAs are of little pharmaceutical interest, they are converted commercially to the highly active PGFj, and PGEj (G.L. Bundy, 1971, 1972). 

Covalent synthesis of complex molecules involves the reactive assembly of many atoms into subunits with aid of reagents and estabUshed as well as innovative reaction pathways. These subunits are then subjected to various reactions that will assemble the target molecule. These reaction schemes involve the protection of certain sensitive parts of the molecule while other parts are being reacted. Very complex molecules can be synthesized in this manner. A prime example of the success of this approach is the total synthesis of palytoxin, a poisonous substance found in marine soft corals (35). Other complex molecules synthesized by sequential addition of atoms and blocks of atoms include vitamin potentially anticancer KH-1 adenocarcinoma antigen,... 

Discredited Synthetics. There are several materials that have in the past been considered to be synthetics, but were found on closet examination not to deserve such a designation, being merely imitations. Examples include imitation coral, lapis la2uli, and turquoise, all made by ceramic processes. This same point has been raised (17) with respect to synthetic opal, which does contain some substances not present in natural opal and somewhat less water. However, the composition of natural opal is quite variable and is usually intermixed with significant amounts of rock-derived materials hence the synthetic designation is usually retained. 

Harth-Hoehzein, World Hydrogen Energy Conference, Coral Gables, Ela., 1974. 

L. W. Jones, World Hjdrogen Energy Conference, lC-61, University of Miami, Coral Gables, Fla., 1976. 

Definitions. In addition to showing varying degrees of chemical purity, limestone assumes a number of widely divergent physical forms, including marble, travertine, chalk, calcareous mad, coral, shell, ooHtes, stalagmites, and stalactites. AH these materials are essentially carbonate rocks of the same approximate chemical composition as conventional limestone (2—4). 

The ocean is host to a variety and quantity of inorganic raw materials equal to or surpassiag the resources of these materials available on land. Inorganic raw materials are defined here as any mineral deposit found ia the marine environment. The mineral resources are classified generally as iadustrial minerals, mineral sands, phosphorites, metalliferous oxides, metalliferous sulfides, and dissolved minerals and iaclude geothermal resources, precious corals, and some algae. The resources are mosdy unconsoHdated, consoHdated, or fluid materials which are chemically enriched ia certain elements and are found ia or upon the seabeds of the continental shelves and ocean basias. These may be classified according to the environment and form ia which they occur (Table 1) and with few exceptions are similar to traditional mineral deposits on land. 

Aragonite. Calcium carbonate is a common deposit in shallow tropical waters as a constituent of muds, or in the upper part of coral reefs where it precipitates from carbon dioxide-rich waters supersaturated with carbonate from intense biological photosynthesis and solar heating. Deposits of ooHtic aragonite, CaCO, extending over 250,000 km in water less than 5 m deep ate mined for industrial purposes in the Bahamas for export to the United States (19). 

Precious Corals. One important deep seabed resource having worldwide distribution is precious coral. The industry extends worldwide, but the richest beds... 

Pu(N03 ) -5H2 0 deep red plutonyl nitrate hexahydrate [19125-90-7], Pu02(N03 )2-6H2 0 coral red anhydrous plutonium(IV) sulfate [13692-89-2], Pu(S0 2i pinh or redPu(S0 2 4H20 and moss green plutonyl carbonate/ P2P2-/(9-P/, PUO2CO2 (30). 

The leading manufacturers in the poHsh categories are S. C. Johnson Son, Inc., Reckitt Coleman, Sara Lee, Scotts Liquid Gold, Turtle Wax, and Alberto Culver for furniture poHshes S. C. Johnson Son, Inc, and L F Products for household floor poHshes S. C. Johnson Son, Inc., Pioneer-EcHpse, Spartan Chemical, HiHyard Chemical Co., and Butcher Co. for industrial and institutional floor poHshes Turtle Wax, Armor AH, Eirst Brands, Kit Products of Northern Labs, Meguires, Blue Coral, and Nu-Finish for automotive poHshes and Kiwi for shoe poHshes (68—72). 

Thorium isotope concentrations and ratios, as well as parent and daughter isotope concentrations, are used to date and study the formation and metamorphosis of rocks and sediments. For example, has been used to date coral reef terraces (4). / Th disequiUbria and Th/ Th... 

The oceans contain vast quantities of ionic calcium,, to the extent of 400 mg/L of seawater (3). Calcium is present ia living organisms as a constituent of bones, teeth, shell, and coral. It is essential to plant as well as animal life. 

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