A protonated form of carbonyl sulfide – HOCS⁺ – was detected toward the central galactic source G+0.693-0.027 by Sanz-Novo and co-workers, as reported in 2024. The observations were made with the Yebes 40m telescope and IRAM 30m telescope. OCS can be protonated at all three atoms, with the terminal O and S atoms energetically preferred (as shown by Wheeler and co-workers and others; protonation at the C atom yields a much less stable cyclic structure). The HSCO⁺ isomer was sought for but not detected by Sanz-Novo and co-workers toward G+0.693-0.027, even though it is slightly more stable than HOCS⁺. If HOCS⁺ is predominantly formed via protonation of OCS by abundant cations such as H₃⁺ and HCO⁺ as suggested by Sanz-Novo and co-workers, HOCS⁺ may be preferentially formed over HSCO⁺ because the polarization in OCS results in negative charge on O and positive charge on S.