Optical and EPR centres involving 3d metals in diamond

Many fewer 3d ions are known to be incorporated at lattice sites (both substitutional and interstitial) in point defects in diamond than in silicon. In diamond, only nickel and cobalt have been positively identified. There appears to be a great variety of nickel-containing sites, and several different cobalt-containing sites, some of these also involving substitutional nitrogen. The evidence for incorporation of other 3d atoms is much less certain, but there is possibly some for Ti, Cr, Mn, Fe, Cu and Zn. Some general inferences may be drawn from these data.