A new three-dimensional (3D) zeolite-type zirconogermanate, (C4N2H12)[ZrGe4O10F 2] (designated as FDZG-1), with a low framework density of 13.5 T/1000 Å3, has been hydrothermally synthesized by using organic piperazine as template and the inorganic salt ZrO(NO3)2·2H2O as the zirconium source at 160 °C in a mixture of pyridine and water as solvent. Single-crystal X-ray analysis reveals that its framework structure is constructed from a spiro-5 second building unit (SBU) or a parallelepiped-like building block and has a similar topology to cavansite (Ca(VO)Si4O10·4H2O). Large elliptic 10-membered ring channels are clearly observed along the crystallographic c axis and blocked by terminal fluorine atoms. Diprotonated piperazinium cations are located in the cavity center of its parallelepiped building block and form strong hydrogen bonds with oxygen atoms and fluorine atoms in the framework. This compound is not stable towards thermal removal of the organic template at above 350 °C.