ULTIMATE ANALYSIS OF COAL AND COKE IS DEFINED IN ASTM D 3176 as the determination of the carbon and hydrogen in the material, as found in the gaseous products of its complete combustion, the determination of sulfur, nitrogen, and ash in the material as a whole, and the estimation of oxygen by difference. The carbon determination includes that present in the organic coal substance and any originally present as mineral carbonate. The hydrogen determination includes that in the organic materials in coal and in all water associated with the coal. All nitrogen determined is assumed to be part of the organic materials in coal. For practical reasons, sulfur is assumed to occur in three forms in coal: as organic sulfur compounds, as inorganic sulfides, which are mostly the iron sulfides pyrite and marcasite, and as inorganic sulfates. The total sulfur value is used for ultimate analysis.