[CN3H6]2[Zn(CO3)2], the first organically templated open-framework carbonate

[CN3H6]2[Zn(CO3)2], the first organically templated open-framework carbonate has been synthesized hydrothermally and its single crystal structure and some properties have been determined. This phase is built up from a three-dimensional framework of vertex-linked ZnO4 and CO3 building units encapsulating the extra-framework guanidinium cations. Template-to-framework hydrogen bonding appears to play an important role in stabilizing the structure. The zincocarbonate framework shows a surprising similarity to those of known zinc phosphates and phosphites.