Barium Azacryptand Sodide, the First Alkalide with an Alkaline Earth Cation, Also Contains a Novel Dimer, (Na<sub>2</sub>)<sup>2-</sup> Mikhail Y. Redko Rui H. Huang James E. Jackson James F. Harrison James L. Dye 10.1021/ja027241m.s001 https://acs.figshare.com/articles/journal_contribution/Barium_Azacryptand_Sodide_the_First_Alkalide_with_an_Alkaline_Earth_Cation_Also_Contains_a_Novel_Dimer_Na_sub_2_sub_sup_2-_sup_/3644742 The first barium sodide, with stoichiometry Ba<sup>2+</sup>(H<sub>5</sub>Azacryptand[2.2.2]<sup>-</sup>)Na<sup>-</sup>·2MeNH<sub>2</sub>, was synthesized by the reaction of Ba, Na, and H<sub>6</sub>Azacryptand[2.2.2] in NH<sub>3</sub>−MeNH<sub>2</sub> solution. It was characterized by X-ray crystallography, <sup>23</sup>Na MAS NMR, hydrogen evolution, DSC, optical spectroscopy, and magnetic susceptibility. This is the first sodide in which the sodium anions form (Na<sub>2</sub>)<sup>2-</sup> dimers. Previous theoretical predictions were verified by a calculation of the potential energy curve for the dimer in the field of the surrounding charges, whose positions were determined from the crystal structure. 2003-01-29 00:00:00 Na 2 NH sodium anions form Alkaline Earth Cation MeNH sodide DSC Barium Azacryptand Sodide 23 Na MAS NMR