From tin(II) to tin(IV): Following solid‐liquid reactions by microscopy

In order to study the formation of complexes independently from stoichiometry we developed a microscale experiment that allows us to monitor the reaction progress by light microscopy In the present study, the complex formation between SnF2 and 1,10‐phenanthroline (phen) with N,N‐dimethylformamide as solvent was investigated over a period of some weeks. By use of this setup, the formation of three different crystals has been observed, whose compositions and structures were determined by single crystal X‐ray diffraction: 3SnF2 · phen, 1, 2SnF2 · SnF4 · phen, 2, SnF4 · phen, 3. While the octahedral fluorine environment of the tin(IV) atoms of 2 and 3 is very regular, the coordinations of the tin(II) atoms in 1 and 2 is irregular. Assuming a non‐bonding 5s electron pair, classical 2c‐2e‐ and symmetrical and asymmetrical, hypervalent 3c‐4e‐bonds ‐ all based on the orthogonal p atomic orbitals of Sn – an approach to analyse and describe these coordinations in a simple comprehensive way is presented.