OCS versus H₂S comparison in the sources where H₂S was detected. The color of the markers represents bolometric temperature (side colorbar). Left: column densities. The OCS column density increases with increasing H₂S column density. We see two different trends in this graph: (1) Several sources have H₂S/OCS ratios around ~7–10, which we classify as OCS-poor sources. (2) The rest of the sources present H₂S/OCS ratios in the ~0.1–1 range, and most of them are arranged in a cluster of several points in the {N(OCS)~2×l0¹⁵cm^–2, N(H₂S) ~2×l0¹⁴cm^–2} range. They are classified as OCS-rich sources. Right: abundances. We find similarities with the first graph: The OCS abundances grow together with H₂S abundances, the lower H₂S/OCS ratio sources follow a linear (log) trend, and the rest are very differentiated from the fitted line. In this case, the fit corresponds to H₂S/OCS ratio of 0.147±0.022.