Alkalimetallbismutide ABi und ABi2 (A=K, Rb, Cs) - Synthesen, Kristallstrukturen, Eigenschaften

Abstract

The Zintl phases ABi (A = K/Rb/Cs; monoclinic, space group, P2 1/c, a = 1422.3(2)/1474.2(2)/1523.7(3), b = 724.8(1)/ 750.2(1)7773.7(1), c = 1342.0(2)/1392.1(2)/1439.9(2)pm and β = 113.030(3)/113.033(2)/112.722(3)°, Z = 16) crystallize with the β-CsSb structure type containing chains of two-connected Bi atoms. Hence, and according to calculated electronic structures, they are semiconductors with small band gaps of approx. 0.5 eV. In contrast, the compounds ABi2 (A = K/Rb/Cs; cubic, space group Fd3̄m, a = 952.1(2)/962.4(8)/972.0(3) pm, Z = 8) belong to the Laves phases, showing a typical metallic electrical conductivity and no band gaps.