We report on the synthesis of polycrystalline molybdenum oxide (MoO3) nanowires via oxidation of molybdenum-sulfur-iodine (Mo6S2I8) nanowires. This unique synthesis route results in an interesting morphology comprising porous nanowires and nanotubes. We found the nanowires to have the orthorhombic MoO3 structure. The structure is slightly oxygen deficient which results in the appearance of a new resonant Raman band (1004 cm(-1)) and paramagnetic defects (Mo5+) of both the point and crystallographic shear plane nature. (C) 2015 Elsevier B.V. All rights reserved.