Todorov Iliya, Sevov Slavi C
Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
Inorg Chem. 2004 Oct 4;43(20):6490-4. doi: 10.1021/ic0491837.
The title compounds were prepared by direct reactions of the corresponding elements at high temperature. They are isostructural with each other (monoclinic, P2(1)/m, Z = 2; Na(8)BaPb(6), a = 13.116(4), b = 5.351(1), and c = 16.166(5) A, beta = 108.07(2) degrees; Na(8)BaSn(6), a = 12.897(4), b = 5.362(1), and c = 16.826(5) A, beta = 108.19(2) degrees; Na(8)EuSn(6), a = 12.912(2), b = 5.220(1), and c = 15.721(2) A, beta = 108.09(1) degrees ) and contain isolated, flat, and aromatic pentagonal rings of Sn(5)(6)(-) and Pb(5)(6)(-) as well as isolated anions of Sn(4)(-) and Pb(4)(-). According to four-probe conductivity measurements, the tin compounds, Na(8)BaSn(6) and Na(8)EuSn(6), are semiconducting with band gaps of 0.11 and 0.09 eV, respectively, and are therefore electronically balanced. Magnetic measurements show that Na(8)BaSn(6) is diamagnetic while Na(8)EuSn(6) is paramagnetic and undergoes two transitions at low temperatures.
标题化合物是通过相应元素在高温下直接反应制备的。它们彼此同构（单斜晶系，P2(1)/m，Z = 2；Na(8)BaPb(6)，a = 13.116(4)，b = 5.351(1)，c = 16.166(5) Å，β = 108.07(2)°；Na(8)BaSn(6)，a = 12.897(4)，b = 5.362(1)，c = 16.826(5) Å，β = 108.19(2)°；Na(8)EuSn(6)，a = 12.912(2)，b = 5.220(1)，c = 15.721(2) Å，β = 108.09(1)°），并包含孤立的、扁平的、芳香性的Sn(5)(6)(-)和Pb(5)(6)(-)五角环以及孤立的Sn(4)(-)和Pb(4)(-)阴离子。根据四探针电导率测量，锡化合物Na(8)BaSn(6)和Na(8)EuSn(6)是半导体，带隙分别为0.11和0.09 eV，因此电子是平衡的。磁性测量表明，Na(8)BaSn(6)是抗磁性的，而Na(8)EuSn(6)是顺磁性的，并且在低温下经历两次转变。
