14 N nuclear quadrupole resonance (NQR) relaxations in mixed crystals Na 1−x Ag x NO 2 (0 ≤ x ≤ 0.16) have been investigated at room temperature. The spin-spin relaxation time (T 2 ) increases rapidly with the increasing Ag + -concentration up to x ∼ 0.01. Above this concentration, it remains essentially constant, indicating a typical rigid lattice behavior similar to a previous study. On the other hand, the spin-lattice relaxation time (T 1 ) decreases with the increasing Ag-concentration. This trend appears to be related with the change of the cooperated flipping motion of the NO 2 − -ion group.