Where P 0 i is previously defined in equation 15c and i can be either CO To obtain some insights on the importance of this truncation, we choose pure component isotherms from one of the exemplar structures shown in Figure . We mimic the case in which we can only have data up to maximum pressure, which is a fraction of the saturation pressure, by truncating the corresponding CO 2 and N 2 pure component isotherms at different pressures. Those isotherms are then used along with pyIAST to predict binary data at 25°C, 1.01325 bar and different gas compositions (10% and 90% CO 2 ). The binary data predicted using the extrapolated incomplete isotherms is compared to the binary data predicted using the complete pure component isotherms, by computing the relative error for CO 2 and N 2 .