C_4R_4(见图1-1—5)和Li_4R_4(见图1-6—8)具有特殊的四面体结构,近年来颇引人注目。有关这类化合物合成和特性的详细报道可参阅文献[1—12]。我们的兴趣则在于研究此类特殊四面体所引起的键的“弯曲效应”,以便对 C_4R_4 (see Figure 1-1-5) and Li_4R_4 (see Figure 1-6-8) have special tetrahedral structures that have drawn considerable attention in recent years. A detailed report on the synthesis and properties of these compounds can be found in [1-12]. Our interest lies in studying the “bending effect” of the bonds caused by this particular tetrahedron so that