摘要： The basic and the charge density wave (CDW) structures of the monoclinic NbS3-II polymorph were studied by synchrotron x-ray diffraction, ab initio calculations, simulation of electron diffraction patterns, and by atomic-resolution transmission electron and low-temperature scanning tunneling microscopies. It is con?rmed that the basic structure belongs to the space group P 21/m and is described with a unit cell, formed of four pairs of symmetry-related trigonal prismatic (TP) columns [a0 = 0.96509(8) nm, b0 = 0.33459(2) nm, c0 = 1.9850(1) nm, and β0 = 110.695(4)?]. The incommensurate components of the two CDWs, (cid:3)q1 = (0, 0.298, 0) and (cid:3)q2 = (0, 0.352, 0), are related as q1b + 2q2b ≈ 1. Both CDWs form their own modulation patterns with unit cells (am = 2a0, bm = b0/qjb, cm = c0, βm = β0) and are ordered along adjacent isosceles TP columns either pairwise or with both columns modulated by either the (cid:3)q1 or (cid:3)q2 CDW only. The CDWs are ordered according to one of the two possible modulation pattern space groups, Cm or C2/m. If considered as long-period commensurate, the entire modulated structure with both CDWs included is described within experimental error with an enlarged unit cell (a = 2a0, b = 37b0, c = c0, and β = β0) and with all atoms displaced from their average positions in accord with the speci?ed modulation pattern.