A new 2D magnetic member of the MUV-1 family has been reported, incorporating F groups at the surface of the layers. The big size, high crystallinity and robustness of the pristine crystals allows to explore the 2D limit. In general, the known 2D inorganic magnetic materials (metal halides, for example) are chemically unstable in open air. The MUV-1 family has shown to be more stable than these inorganic layered materials opening the door to construct mechanical/magnetic devices or to study exotic phenomena in the 2D regime. Still, some oxidation of the Fe(II) has been detected in the exfoliated layers. Here, the possibility of functionalizing the MUV-1 layers with fluorine has enhanced the stability of these 2D antiferromagnets, while keeping its magnetic properties. This feature may be useful to prepare van der Waals heterostructures based on these molecular magnetic layers, a possibility that so far has only been exploited in inorganic layers.