In recent years, progress in the field of frustrated magnets have led to the emergence of innovative concepts including new phases of matter. The latter’s do not show any long-range order (no symmetry breaking), but, in classical systems, exhibit a highly degenerate ground state made of classical configurations. An emblematic example is spin ice in pyrochlores : in this case, the construction of those configurations relies on a simple rule, which states that the sum of the four spins in any tetrahedron of the magnetic lattice must be zero. Experimental evidence of this physics was provided by the observation of singular points in the spin-spin correlation function by elastic neutron scattering experiments. Recently, several authors have proposed a generalization of this concept to other geometries and other constraints, as for instance the “octochlore” lattice, formed by corner sharing octahedra. Depending on the chosen constraint, different spin liquids have been theoretically predicted. The goal of the work will be to characterize the ground state of two such systems (KRE3F10, with RE = Dy3+, Er3+).