(3.4.6) Gagliardi : Another class of systems where Kohn-Sham DFT encounters some challenges is the determination of the spin ladder in multi-metallic compounds. Some of these compounds are molecular magnets with potential applications in information storage, quantum computation, and molecular electronics. In compounds containing several magnetic centres, the spin carriers can magnetically interact in many ways. A prototypical system is a tris-hydroxo-bridged Cr(III)-Cr(III) system (Kremer's dimer), 361 which consists of two antiferromagnetically coupled Cr(III) metal centres with a d3-d3 electron configuration.