Cloudy model for the HVC at v_LSR = −257 km s⁻¹ in the direction of MR 2251−178. Solid, dashed, and dash-dotted lines represent column densities predicted by the Cloudy model for different ions, while the symbols (dots, star, and triangles) show the measured values. This model, with log N(H I) = 16.53, fits Si II, Si III, Si IV, and C II at log n_H = −3.78, which is indicated by the black dotted line.