We have performed the investigation of the charge density distribution of CeT2Al10 (T = Ru, Fe) and the crystal structure parameters of LnT2Al10. The lattice parameters of a-, b-, and c-axes exhibit the anisotropic contraction when Ru is replaced by Fe in LnT 2Al10, different from the isotropic contraction simply expected from the smaller ionic radius of Fe than Ru. The contraction is larger in the a- and c-axes than in the b-axis. This anisotropic contraction of the YbFe2Al10-type crystal structure originates from the zigzag degree of the zigzag chain formed by T and Al bond along the a- and c-axes are larger than that along the b-axis. The lattice parameters of CeT 2Al10 (T = Ru, Fe) exhibit the anisotropic deviation from the lanthanide contraction. The deviation is largest in the a-axis and is very small in the b-axis. Both the characteristic YbFe2Al 10-type crystal structure and the anisotropic deviation towards the intermediate valence indicate that the largest c-f hybridization along the a-axis plays the important role and is associated with the unusual antiferromagnetic order in CeT2Al10 (T = Ru, Os).
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