1,1'-Di(hydrazinocarbonylmethyl)-2,2'-biimidazole monohydrate and 1,1'-di[2-(hydrazinocarbonyl)ethyl]-2,2'-biimidazole.

The crystal structures of the title compounds, alternatively called 2,2'-(2,2'-biimidazole-1,1'-diyl)diacetohydrazide monohydrate, C(10)H(14)N(8)O(2).H(2)O, (I), and 3,3'-(2,2'-biimidazole-1,1'-diyl)dipropionohydrazide, C(12)H(18)N(8)O(2), (II), respectively, have been determined. The molecules consist of half-molecule asymmetric units related by a twofold rotation in (I) and by a center of inversion in (II). The imidazole rings of both molecules crystallize in a nearly coplanar fashion [dihedral angles of 5.91 (3) and 0.0 (1) degrees for (I) and (II), respectively]. Both planar hydrazinocarbonylalkyl substituents are essentially planar and assume the E orientation.