Crystalline modifications of cellulose. Part VI. Unit cell and molecular symmetry of cellulose I

A study of the electron diffraction diagram of Valonia ventricosa cellulose has confirmed the conclusions reached by Honjo and Watanabe concerning the size of its unit cell. The a and c axes of the cell are twice the length of those usually accepted for cellulose I. The symmetry of the cell is P 1, but the evidence available at present does not allow a decision to be made concerning the symmetry of the molecular chains. Consideration of x‐ray diffraction and infrared spectroscopic data suggests that bacterial cellulose probably has the same unit cell as Valonia ventricosa , but that other native celluloses may have different cells.