Aluminum-rich cage compounds <i>AT</i> ₂ Al ₂₀ ( <i>A</i>  = Sr, Eu; <i>T</i>  = Ti, V)

Abstract The CeCr 2 Al 20 -type (space group Fd 3− m ) aluminum-rich intermetallic compounds AT 2 Al 20 ( A = Sr, Eu; T = Ti, V) were synthesized from the elements in alumina crucibles within evacuated sealed silica ampoules and characterized through X-ray powder patterns. SrTi 2 Al 20 ( a = 1,475.25(6) pm) and SrV 2 Al 20 ( a = 1,459.81(8) pm) are the first strontium-based aluminides with CeCr 2 Al 20 -type structure. The structures of Sr 0.836(2) V 2 Al 20 , Sr 0.961(1) V 2 Al 20 and Eu 0.964(2) V 2 Al 20 were refined from single crystal X-ray diffractometer data. Refinements of the occupancy parameters revealed defect formation on the 8 a sites. In the strontium series, the lattice parameter scales with the occupancy parameter. Temperature dependent magnetic susceptibility data for the SrTi 2 Al 20 and SrV 2 Al 20 samples show diamagnetic and Pauli paramagnetic behavior, respectively.