Tl₂Ch₂^2-(Ch = Se and/or Te) Anions:  X-ray Crystal Structures and Raman Spectra of (2,2,2-crypt-K⁺)₂Tl₂Se₂^2-and (2,2,2-crypt-K⁺)₂Tl₂Te₂^2-and Solution⁷⁷Se,²⁰³Tl, and²⁰⁵Tl NMR Spectroscopic and Theoretical Studies of Tl₂Ch₂^2-, In₂Se₂^2-, and In₂Te₂^2- Journal Articles