Ca8In3, a structure related to the BiF3 type

Mr=665.1, triclinic, aP22, P1, a=9.606(2), b=9.717(2), c=9.782(2) A, α=69.65(2), β=78.85(2), γ=60.34(1)0, V=743.7(3) A3, Z=2, Dx=2.97 Mg m-3, MoKα, λ=0.7107 A, μ=7.13 mm-1, F(000)=614, room temperature, R=0.027 for 2789 reflections with F0>3σ(F0). The Ca8In3 structure is derived by distortion of the face-centered cubic BiF3 type (also called AlFe3 or BiLi3 type). It can be described as a three-layered structure along the a axis, the atoms being located at x≅0, x≅1/3 and x≅2/3. Three different coordination polyhedra are found around the In atoms: distorted cubicosahedra (ten-vertex polyhedra) for In(1), In(2), In(4) and In(6), cubes for In(3) and icosahedra for In(5). Distorted cubicosahedra centered by In at x≅0 and x≅1/3 are alternately joined by an edge and by a face and form parallel rows; cubes and icosahedra centered by In at x≅2/3 are joined by an edge and also form parallel rows. (orig.)