code: def structure(self):
          
          masses = self.masses
          atoms = self.atoms.copy()
          if "nx" in atoms.columns:
              atoms.drop(["nx", "ny", "nz"], axis=1, inplace=True)
          atoms["molecule-ID"] = 1
          ld_copy = self.__class__(self.box, masses, atoms)
          topologies = ld_copy.disassemble()[-1]
          molecule = topologies[0].sites
          coords = molecule.cart_coords - np.array(self.box.bounds)[:, 0]
          species = molecule.species
          latt = self.box.to_lattice()
          site_properties = {}
          if "q" in atoms:
              site_properties["charge"] = atoms["q"].values
          if self.velocities is not None:
              site_properties["velocities"] = self.velocities.values
          return Structure(latt, species, coords, coords_are_cartesian=True,
                           site_properties=site_properties)
docs: Exports a periodic structure object representing the simulation
          box.
  
          Return:
              Structure