IIRC, the surface temperature on Venus is in the 800-900 degree range. Different gases react to temperatures in their own way, so it’s not unreasonable to expect that they might stratify into layers.
3 posted on 04/22/2020 9:24:22 AM PDT by JimRed
(TERM LIMITS, NOW! Build the Wall Faster! TRUTH is the new HATE SPEECH.)