but forms a hydroxyl group that points towards the ring centre (Figure ). As is the convention for interrupted frameworks, the structure commission of the International Zeolite Association (IZA) assigned a framework type code with a leading hyphen to the cloverite structure: -CLO. The crystal structure of cloverite, determined from single-crystal X-ray diffraction measurements, is cubic, space group 𝐹𝑚3 𝑐, with a very large unit cell (a = 52.712 Å). While the positions of framework atoms (including dangling O atoms) and fluoride anions incorporated in the double four-membered rings (d4r units) could be refined, a refinement of the positions of OSDA molecules and of hydrogen atoms of the hydroxyl groups remained elusive. This crystal structure is available from the IZA Structure Database (IZADB) in CIF format. The content of the conventional cubic unit cell is Ga768P768O2976(O_OH)192F192, where O_OH is used as a label to distinguish dangling oxygen atoms from those belonging to Ga-O-P linkages. It has been postulated that the negative charge of -384 e per unit cell is balanced by protons of hydroxyl groups and quinuclidinium cations in equal amounts (192/192). Concurrent removal of OSDA cations and fluoride anions through calcination results in a neutral compound with accessible porosity. 5 Subsequent experimental investigations focused on various properties of cloverite, such as its thermal stability and dehydration/defluorination behaviour, 4,5 adsorption properties and its potential use in gas-phase catalysis. Although the framework remains intact after calcination, this detemplated form is unstable in the presence of water or other polar molecules, and can only be stabilised by blocking the pores, for example, using silanes. The low stability of cloverite (together with the rather high cost of gallium) severely limits its potential applicability in separation and catalysis, despite the large pore openings. In 2010, an aluminophosphate analogue of cloverite was reported. While it is more stable than the gallophosphate, the calcined form still shows significant decrease in crystallinity upon exposure to ambient air for several days. PKU-12, a germanosilicate having the -CLO topology, is also unstable in the presence of water.