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The temperature dependence of the Cr-Nd energy transfer is found to be due to the thermal variation of the radiative decay probability of Cr. The validity of this conjecture is checked in the Gd3Sc2Ga3O12 and CaMg2Y2Ge3O12 crystals. It is also found that above 200 K, the nonradiative energy transfer rate from Cr to Nd is greater in Gd3Sc2Ga3O12 than in CaMg2Y2Ge3O12.
Nd3Cr is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Nd sites. In the first Nd site, Nd is bonded to eight Nd and four equivalent Cr atoms to form distorted NdNd8Cr4 cuboctahedra that share corners with twelve equivalent NdNd8Cr4 cuboctahedra, edges with eight equivalent NdNd8Cr4 cuboctahedra, edges with eight equivalent CrNd12 cuboctahedra, faces with four equivalent CrNd12 cuboctahedra, and faces with ten equivalent NdNd8Cr4 cuboctahedra. There are four shorter (3.42 Å) and four longer (3.52 Å) Nd–Nd bond lengths. All Nd–Cr bond lengths are 3.52 Å. In the second Nd site, Nd is bonded in a distorted square co-planar geometry to eight equivalent Nd and four equivalent Cr atoms. All Nd–Cr bond lengths are 3.42 Å. Cr is bonded to twelve Nd atoms to form CrNd12 cuboctahedra that share corners with four equivalent CrNd12 cuboctahedra, edges with eight equivalent CrNd12 cuboctahedra, edges with sixteen equivalent NdNd8Cr4 cuboctahedra, faces with four equivalent CrNd12 cuboctahedra, and faces with eight equivalent NdNd8Cr4 cuboctahedra.