Outside the ISS in the orbital night, the temperature can reach -250 degrees Fahrenheit (-157 degrees Celsius). The ECLSS (Environmental Control System and Life Support System), more specifically the OGA sub-system (Oxygen Generation Assembly) vent overboard Hydrogen in the electrolysis process to produce oxygen from water, and the sub-system CDRA (Carbon Dioxide Removal Assembly) vent CO2 overboard ISS too. At orbital night temperature, or even in the penumbra / terminator area, could these gases (I´m not sure if the H2 is maintained gas or liquid before to be vented) become flakes of ice when ventilated outboard? CO2 could become flakes of dry ice?
(EDITED by the comment of a friend below): The solidification point of the hydrogen gas is close to -259° C. And the solidification point of carbon dioxide is -56 ° C. But I am not sure if other factors (pressure, vacuum...) would interfere with this process.
I found this question here also refers to H2 and CO2 vent outboard. Why vent CO2 and H2 waste products to space on ISS?
Just for reference, before part of hydrogen was used in a Sabatier reactor, but it was removed and returned to ground tests (2017) Why was the Sabatier system removed from the ISS USOS?