SYNTHESIS, STRUCTURE, AND PROPERTIES OF A14ALSB11 (A=CA, SR, BA)

A14AlSb11 (A = Ca, Sr, Ba) is synthesized by reacting the elements in stoichiometric amounts at high temperature (1250°C). Single-crystal X-ray diffraction data (130 K: a = 17.493 (4) Å, c = 23.480 (8) Å (Sr); a = 18.293 (2) Å, c = 24.222 (9) Å (Ba)) were refined (tetragonal, I41/acd (142), Z = 8; R = 4.02%, Rw = 4.26% (Sr); R = 3.71%, Rw = 4.34% (Ba)) and showed these compounds to be isostructural to Ca14AlSb11. Single-crystal X-ray and microprobe data indicate that these compounds are slightly deficient in Al. Temperature-dependent resistivity measurements show that these materials are intrinsic semiconductors with activation energies of 0.0143, 0.0667, and 0.4814 eV for the Ca, Sr, and Ba analogs, respectively. © 1993 Academic Press, Inc.