Energy transfer processes in EuMgB 5 O 10 doped with Nd 3+ or Ni 2+ have been evaluated. This host lattice contains linear Eu 3+ chains. Energy migration occurs down to low temperatures. At low temperatures mainly Eu 3+ traps act as acceptors, at higher temperatures the intentionally added impurities, and defects of an unknown nature take over. The energy migration is proved to be one-dimensional; the transfer probabilities in and between the linear chains are estimated and differ by orders of magnitude. The critical interaction distances between regular Eu 3+ ions (donors) and Eu 3+ ions and Ni 2+ ions (acceptors) are determined. The temperature dependence of the transfer processes is explained by phonon assistance.