CaF2: The mother of all fluorine compounds

FLUO 42

Herbert W. Roesky, hroesky@gwdg.de, Institute of Inorganic Chemistry, University of Goettingen, Tammannstrasse 4, 37077 Goettingen, Germany
The usability of CaF2 as a flux was already known in the middle ages and C.W. Scheele discovered the preparation of HF from CaF2 using sulfuric acid. There is hardly any chemistry known of CaF2 or derivatives of this compound. The preparation of the first monofluoride of composition LCaF (L = HC(CMeNAr)2) is reported. LCaF is soluble in hydrocarbon solvents in contrast to CaF2. Therefore LCaF and their precursor can be used in the presence of pyridine x HF to deposit on silicon thin layers of CaF2 at room temperature from organic solvents. The isoelectronic LCa(OH) is also soluble in well-defined hydrocarbon solvents and was prepared from LCaN(SiMe3)2 in the presence of small amounts of water. The magnesium analogues will also be reported. A comparison of calcium with germanium(II) of the same row having two additional electrons in the valence shell will be discussed. The structurally characterized isolobal germanium(II) compounds of composition LGeCl, LGeF, LGeOH, and LGeH will be presented.