A short discussion on the chemical composition of allophane based on the data of Yoshinaga in 1966

Many scientists have attempted to discern the chemical composition and the structure of allophane (2, 4–6). Yoshinaga (7) presented the chemical composition of eighteen samples of pure allophane in detail, and concluded as follows: All samples consisted principally of silica, alumina, and water. The silica-alumina molecular ratio ranged from about 1.3 to 2. Molecular ratios of ignition loss (+H₂0) and total water (±H₂O) to alumina were nearly constant, with the averages about 2.5 and 5.7, respectively. The chemical composition of soil allophane fell into a relatively narrow range, and the change in the percentage composition of the three major elements had a regularity.