Syntheses; 77Se, 203Tl, and 205Tl NMR; and Theoretical Studies of the Tl2Se6 6-, Tl3Se6 5-, and Tl3Se7 5- Anions and the X-ray Crystal Structures of [2,2,2-crypt-Na]4[Tl4Se8]·en and [2,2,2-crypt-Na]2[Tl2Se4]∞ 1·en

The 2,2,2-crypt salts of the Tl4Se8(4-) and [Tl2Se4(2-)]infinity1 anions have been obtained by extraction of the ternary alloy NaTl0.5Se in ethylenediamine (en) in the presence of 2,2,2-crypt and 18-crown-6 followed by vapor-phase diffusion of THF into the en extract. The [2,2,2-crypt-Na]4[Tl4Se8].en crystallizes in the monoclinic space group P2(1)/n, with Z = 2 and a = 14.768(3) angstroms, b = 16.635(3) angstroms, c = 21.254(4) angstroms, beta …