A true square-planar tin(<scp>II</scp>) spiro complex: molecular structure of bis(imidotetraphenyldiselenodiphosphino-Se,Se′)tin(<scp>II</scp>) and its distorted tetragonal-pyramidal isomer

The yellow complex [Sn{N(SePPh2)2-Se,Se′}2] is the first example of a true square-planar spiro tin(II) compound; the structure of the distorted tetragonal-pyramidal isomer is also described.