Abstract
A central dogma is that fluorine is the most electro negative element in the PSE and would thusact as a pure electron acceptor. However, to some chemists it is known, that fluorine can bond induality. This means fluorine can act as a donor and an acceptor of bonds and thus electrons. Thedonor/acceptor properties of fluorine are known from the NF molecule, where a partial double bondcharacter is present[1]. Up to now, however, chemists are not aware that fluorine may form even triple bonds, something that other elements from the second row of the PSE do as well. The subsequent work investigates theoretically the possibility of triple bonds between fluorine and Mn in a heterodimer MnF. Moreover, mono fluorides isoelectronic to MnF and higher oxidation states of MnFare investigated. Furthermore, the tendency to form singlets and possibly multi–bonded states is investigated for higher transition metals and halogens as well. It is concluded that first the naive methodology of using Wigner-Witmer rules may find their limit in the case of MnF and isoelectronic compounds as well as higher homologues. Secondly, it is demonstrated that using ECP may lead to misleading results on higher transition metals when calculating heterodimers with halogens.