On oxidation of graphitic carbon, acidic surface oxides (or hydroxides in the presence of water) are formed at the boundaries of the carbon layers. It was found that the reaction of oxygen with microcrystalline carbon at 400-450 "C yields four groups of diflerent acidities. One strongly acidic group and one weakly acidic carboxyl group have been detected, as well us a phenolic hydroxyl group; a carbonyl group is probably also present. With dissolved oxidizing agents, one equiialent of another strongly acidic carboxyl group is formed in addition at room temperature. The possible constitutions o f the acidic surface oxides are discussed. Chemically detectable surface oxides are also formed on the surfarc. of diamond. In the presence of oxygen at 800-900 "C under reduced pressure, diamond is transformed into black carbon. Surface oxides play a par[ in this transjbrmation.

Meine Diskussion ware ohne Erwahnung der a p p r o x im a t i ven Invarianzbeziehung hochst unvollstandig. Wie alle approximativen Beziehungen konnen sie unter bestimniten Bedingungen sehr genau gelten, unter anderen aber ganz entscheidend falsch sein. Die kritischen Bedingungen konnen durch den Zustand des Objektes gegeben sein, oder einen Typ von Phanomenen auszeichnen. Das bedeutendste Beispiel fur die erste Gruppe ist der Fall geringer Relativgeschwindigkeiten. Hier sind die magnetischen Felder schwach, und die Spinrichtungen beeinflussen die anderen Koordinaten nicht. Das fiihrt zur Russell-Saunders-Kopplung in der Spektroskopie [17]. Noch interessanter ist der Fall sehr hoher Geschwindigkeiten, in deni die Ruhmasse vernachlassigbar wird. Leider ist dieses Beispiel noch nicht in aller Ausfuhrlichkeit diskutiert worden, obwohl es vielversprechende Anf ange gibt [ 181. Der vielleicht wichtigste Fall spezieller Phanomene, bei denen mehr Invarianztransformationen als oben aufge-~

The article contains sections titled: 1. Aluminum Sulfate and Alums 1.1. Aluminum Sulfate 1.1.1. Properties 1.1.2. Production 1.1.3. Uses 1.2. Alums 1.2.1. Potassium Aluminum Sulfate 1.2.2. Ammonium Aluminum Sulfate 1.2.3. Sodium Aluminum Sulfate 2. Aluminates 2.1. Sodium Aluminate 2.2. Barium Aluminates 3. Aluminum Alkoxides 4. Aluminum Chloride 4.1. Anhydrous Aluminum Chloride 4.1.1. Properties 4.1.2. Production 4.1.3. Quality Specifications and Analysis 4.1.4. Handling, Storage, and Transportation 4.1.5. Uses 4.2. Aluminum Chloride Hexahydrate 4.3. Basic Aluminum Chlorides 5. Toxicology

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Fires result from just exposing these compounds to air. But handling them is no more difficult than handling strong acid or caustic-if it is done the right way Knowledge is safety-techniques and equipment can be designed to nullify the very dangerous properties of aluminum alkyls. Precautions must be scrupulously observed. Education and training play a most important part in any program of handling aluminum alkyls. All personnel must know thoroughly the nature of the materials, the operating procedures, and the equipment. The need for proper use of personal protective equipment must be deeply ingrained. Personnel must respect these materials-not fear them.Ethyl Corp. has worked with aluminum alkyls for several years in laboratory, pilot plant, and commercial operations. There have been no serious accidents because of the continuing attention given to the proper safety precautions. Cardinal rules to be followed fall into three groups: CONTAIN-Prevent uncontrolled escape of alkyls and contact with reactive materials. GUARD -In case aluminum alkyls should escape from their enclosed system, shield operators and equipment from potential leaks, sprays, or splashes.PROTECT-As a third line of defense, require that personnel wear full personal protective equipment when there is a possibility of exposure.Aluminum Alkyls Are Used by the Ton The term, aluminum alkyls, now often used in the chemical industry, broadly covers the compound family containing aluminum, alkyl groups, and sometimes halogens.Triethylaluminum, triisobutylaluminum, and diethylaluminum chloride are used commercially. Tri-n-propylaluminum, trimethylaluminum, ethylaluminum dichloride, and diethylaluminum hydride may soon have commercial use.Large amounts of aluminum alkyls are used in Ziegler catalyst systems for polyethylene, polypropylene, and stereo rubbers. Triethylaluminum is used in one U. S. plant for making straight chain alcohols; it can also be used for making long-chain alpha olefins. Ethyl Corp. uses the alkyls in their manufacturing operation. Continuing research is leading to new uses: ignitor systems in ramjets, afterburner sustainers for jet engines, aluminum gas plating compounds, high energy fuels, reducing agents, and intermediates for organometallics.New Chemistry-New Hazard Combination Aluminum alkyls are highly reactive. Butyls and the lower alkyls are pyrophoric; that is, they ignite spontaneously in air, at ambient temperatures. They react violently with water, and burn the skin severely on contact.