The main objective of this proposal is the magnetic structure determination of Cu3Mn2F12.12D2O compound, an antiperovskite-like with the formulae ABX3 ([MnF6][MnF6][Cu(H2O)4]3). The nuclear structure symmetry is triclinic with the space group P-1 (but can be described as a pseudocubic). The[MnF6]-3octahedra (site B) with the [Cu(H2O)4] units form bimetallic chains by sharing trans-fluoride anions.These chains run parallel to each crystal axis, alternating two different Jahn-Teller ions (Mn(III) and Cu(II)),giving rise to the final 3D-structure. The magnetic interactions between metal ions produce a ferrimagnetic behaviour with a Curie temperature of 4K. A remanent magnetization is observed below this TC. In the experiment CRG-D1B-13-267 we use a non-deuterated sample and we couldnot solve the magnetic structure, probably due to the very strong incoherent background. In this case we will use full-deuterated samples (powder and singles crystal)