Alkaline earth metal (2: Mg, 3: Ca, 4: Sr, and 5: Ba) salts with the nitrogen-rich 5,5Ј-hydrazine-1,2-diylbis(tetrazolate) anion (HBT 2-) were synthesized in high purities and yields and fully characterized by spectroscopic and analytical methods. In addition, the crystal structures of the new compounds were determined by X-ray diffraction techniques. Whereas the tetrazole rings in 2 are twisted with respect to one another, as reported for compounds with the same anion, in the heavier-metal salts 3-5 there exists "apparent coplanarity" between the same rings due to disorder, which is discussed. A detailed description of the structures is given. The compounds, obtained as the hydrated species, are insensitive to friction, shock, and electrostatic discharge (BAM testing), but react vigorously in a flame upon loss of water to give the