“…Also, the main diffraction peaks at 12.74, 18.06, 28.74, 25.65, 36.59, 38.90, 41.09, 47.18, and 56.18° can be assigned to (110), (200), (220), (310), (400), (330), (420), (510), and (600), respectively. There is no mixed crystalline phase, attesting to the great fineness of the products, and the classical crystal form of α-MnO 2 nanowires features 2 × 2 tunnels, which are composed of [MnO 6 ] octahedral units linked via an edge and/or corners (Figure b). , In Figure c, Raman bands at 644 and 575 cm –1 may be the result of the υ 2 (Mn–O) symmetric stretching vibrations of the [MnO 6 ] octahedron and υ 3 (Mn–O) stretching vibrations in the basal plane of [MnO 6 ], respectively. Moreover, another band at 472 cm –1 corresponds to the υ 4 (Mn–O) stretching vibration .…”