The article contains sections titled: 1. Introduction 2. Chromium Ores 2.1. Ore Deposits 2.2. Ore Beneficiation 3. Production of Sodium Dichromate 3.1. Alkaline Roasting 3.2. Leaching of the Roast 3.3. Acidification 3.4. Crystallization 4. Chromium Oxides 4.1. Chromium(III) Oxide and Chromium Hydroxide 4.2. Chromium(IV) Oxide (Chromium Dioxide) 4.3. Chromium(VI) Oxide 5. Chromium(III) Salts 5.1. General Properties 5.2. Chromium(III) Sulfates and Chrome Tanning Agents 5.3. Other Chromium(III) Salts 6. Chromic Acids and Chromates(VI) 6.1. Chromic Acids 6.2. Alkali Chromates and Dichromates 6.3. Other Chromates 7. Other Chromium Compounds 8. Analysis 9. Transportation, Storage, and Handling 10. Environmental Protection 11. Ecotoxicology 12. Nutrition 13. Toxicology and Occupational Health 14. Economic Aspects

~~ ~~ ~~Das vollstandig silylierte Aminodiiminophosphoran 1 [(CH,),Si],NP[ = NSi(CH3)& (1) reagiert mit Aceton und Acetophenon unter Addition zu den 0-phosphorylierten Enolen 2. Ihre Thermolyse ergibt das Diazadiphosphetidin 3 sowie die entsprechenden Silylenolether 4. Mit Dimethylsulfoxid bzw. Methylphenylsulfoxid setzt sich 1 hingegen unter Reduktion des Schwefelatoms zu den Additionsverbindungen 5 um. On the Different Mode of Addition of Ketones and Sulfoxides to Persilylated Amiinodiiminophosphorme')The persilylated aminodi(imino)phosphorane, (I) adds acetone and acetophenone to give the 0-phosphorylated enoles 2. Thermolysis of 2 yields the diazadiphosphetidine 3 and the corresponding silylenol ethers 4. However, in the reaction of 1 with dimethyl sulfoxide or methyl phenyl sulfoxide the sulfur atom is reduced to a thioether structure with formation of the addition products 5. 861 (1921).

Das vollständig silylierte Aminodiiminophosphoran (I) reagiert mit Aceton und Acetophenon (II) unter Addition zu den O‐phosphorylierten Enolen (III).