Even if a few studies used classical MD to study the amorphization of ZIFs, every classical FF for ZIFs published to this date has been developed for crystals and should thus first be adapted and validated before studying ZIF glasses. In our study, we chose to use the recently developed MOF-FF for ZIFs by Dürholt et al. This force field showed good transferability across a series of ZIF polymorphs, indicating that it can handle various network topologies, and led to mechanical properties in line with earlier FFs. Developing a new FF for glasses from scratch is beyond the scope of this study, but the MOF-FF methodology for an automatic parametrization of FFs would make such a development achievable in future work. While ZIF-4 crystals are made only of Zn(Im) 4 tetrahedra (see Figure ), a number of three-coordinated Zn ions can be found in ZIF-4 glasses, which are not readily parametrized in MOF-FF. On the N-Zn-N bond angle distribution of the ab initio glass shown on Figure , we see that these three-coordinated Zn deviate from the 109 • angle of the tetrahedra. To reproduce the glass properties and test the sensitivity of our results to our adaptation of MOF-FF, we introduced and evaluated two adaptations of the FF, which we name Zn3tetra and Zn3trig which respectively shift the N-Zn-N angle of the three-coordinated Zn towards 109 • or 120 • as shown on Figure . As it features no under-coordinated Zn atoms, the ZIF-4 crystal is simulated with the original FF. In order to evaluate the validity of these FF adaptations, we compared the structural characteristics of ZIF-4 systems simulated with MOF-FF to the original ab initio models, using the same metrics as in our previous work on ReaxFF. An investigation of the local order with the partial radial distribution functions (RDF) and potentials of mean force (PMF) (see Figure ), evidences an excellent reproduction of interatomic distances and similar energy landscapes close to the energy minima. The region between the two minima in PMF is qualitatively different, as MOF-FF is unable by design to simulate non-bonded but nearby Zn-N atoms. Despite differences in the angle distribution of the three-coordinated Zn atoms, Figure shows that the total distribution is similar for both FF adaptations, which reproduce the wider distribution of angles for the glasses than for the crystal. Although affected by the small difference in geometry imposed by the FF adaptations, both FF adaptations lead to glass models of higher porosity than the crystal, as shown on Figure . Finally, as classical MD cannot simulate bond breaking, the coordination and topology (e.g. ring statistics) are automatically preserved. Despite not being developed for ZIF glasses, both FF adaptations reasonably reproduce the structural properties of the ab initio systems, at least compared to the only force field available in the literature for amorphous ZIFs, namely ReaxFF.