Tetra­aqua­bis­(1,10-phenanthroline-κ2 N,N′)strontium 5,5′-diazene­diyl­ditetra­zolide

The title complex, [Sr(C12H8N2)2(H2O)4](C2N10), contains an [Sr(phen)2(H2O)4]2+ cation (phen is 1,10-phenanthroline) and a 5,5′-diazenediylditetra­zolide anion (site symmetry 2). The Sr2+ cation (site symmetry 2) is coordinated by four N atoms from two chelating phen and four water mol­ecules. In the crystal structure, the water mol­ecules and the N atoms in the tetra­zolide rings form an extensive range of O—H⋯N hydrogen bonds which link the complex into a two-dimensional structure. An adjacent layer further yields a three-dimensional supramolecular network by offset face-to-face π–π stacking inter­actions of the phen ligands [with centroid–centroid distances of 3.915 (2) and 4.012 (2) Å]. The two bridging N atoms of the anion are equally disordered about the twofold rotation axis