Synthesis, structure and bonding of the hypoelectronic cluster compound Sr3Tl5

The Sr 3 Tl 5 phase was prepared by high temperature synthesis techniques through reaction of the high purity elements in the welded Nb tubes. The structure established through X-ray structural analysis shows the compound is a good hypoelectronic trielide example of the Pu 3 Pd 5 structural type in which skeletal electron count is lower than in a traditional Zintl phase ( Cmcm , Z = 4; a = 10.604(2) Å, b = 8.675(2) Å, and c = 10.985(2) Å; V = 1010.5(3) Å 3 ). The strontium size and the compound's polarity appear responsible for this thallium phase crystallization in the Pu 3 Pd 5 family type rather than the isoelectronic Sr 3 In 5 version. A first-principle electronic structure calculation (LMTO) demonstrates that the strontium atoms participate substantially in Sr-Tl bonding in the structure.