Finally, every integer was replaced with a word (e.g., "4" with "four"), while real values were replaced with "[REAL-VAL]". The latter replacement was introduced to avoid possible leaks between the values in the CIF files and texts. Sentences that only describe bond lengths and angles were not used. Some examples generated by Robocrystallographer and the preprocessed texts are in the supplementary information. We randomly split the data into a training set consisting of 126035 and a validation set of 14004.