Krogmann s salt has a tetragonal crystal structure with a Pt-Pt distance of 2.880 angstroms, which is much shorter than the metal-metal bond distances in other planar platinum complexes such as Ca [ Pt ( CN ) 4 ] ?H 2 O ( 3.36 angstroms ), Sr [ Pt ( CN ) 4 ] ?H 2 O ( 3.58 angstroms ), and Mg [ Pt ( CN ) 4 ] ?H 2 O ( 3.16 angstroms ).
