Cloud structure and transmission spectrum of a sub-Neptune planet with physical properties similar to GJ 1214 b. The condensate species considered here is NaCl, KCl, ZnS, and Na₂S. In the left panel, the meaning of each line is the same as Figure 8. The cloud is dominated by Na₂S (upper part) and NaCl (cloud bottom). The right panel shows the synthetic spectrum and the blue line shows one set of parameters that leads to flat spectrum in 1 to 2 μm range, consistent with observation (Kreidberg et al. 2014).