play_circle_outlinesugar; sweetness© American Chemical Society (A Britannica Publishing Partner)As a chemical term, “sugar” usually refers to all carbohydrates of the general formula Cn(H2O)n. Sucrose is a disaccharide, or double sugar, being composed of one molecule of glucose linked to one molecule of fructose. Because one molecule of water (H2O) is lost in the condensation reaction linking glucose to fructose, sucrose is represented by the formula C12H22O11 (following the general formula Cn[H2O]n - 1).