(a) Sensitivity coefficients (﹩{S}_{i,{{\rm{CS}}}_{2}}=\frac{d({\rm{ln}}[{{\rm{CS}}}_{2}])}{d({\rm{ln}}{{k}}_{i})}﹩) for the major reactions contributing to CS₂ formation at P ∼ 0.1 mbar, shown in descending order from top to bottom. Briefly speaking, reactions with large positive (negative) sensitivity coefficients promote (suppress) CS₂ formation (see Section 2.4 for the definition and Section 3.3 for further discussion). Among these, S₂ photolysis is identified as the most influential reaction. (b) A schematic diagram illustrating major reaction pathways contributing to the formation of CS₂ at the P ∼ 0.1 mbar region in the simulated atmosphere of TOI-6894 b, under the fiducial model conditions (3× Z_⊙, K_zz = 10⁸ cm² s⁻¹, and T_int = 100 K), corresponding to the results shown in Figure 1. Numbers indicate the logarithm of the absolute reaction rate, in units of molecules cm⁻³ s⁻¹, for each reaction pathway. For example, a value of 5.50 for the S₂ destruction pathway corresponds to a rate of 10^5.50 molecules cm⁻³ s⁻¹ for the reaction S₂ ﹩{\overset{h\nu }{\to }}﹩ S+S reaction. Note that some reactions whose sensitivity coefficients are calculated in panel (a) are omitted from the schematic diagram in panel (b) for visual clarity. As shown, S₂ photolysis, which efficiently liberates two sulfur atoms, plays a key role in CS₂ formation.