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Each thiocyanate is a three-metal bridge, ${\mu }_3$-$\kappa N:\kappa S:\kappa S$: its nitrogen donates to one metal and its sulfur donates to two other metals. Thus the coordination ligand is ambidentate, but the structure uses both ends and shares the sulfur donor. Each metal receives two nitrogen and four sulfur donors, giving an approximately octahedral $\mathrm{M}{\mathrm{N}}_2{\mathrm{S}}_4$ coordination sphere. Six donor contacts per metal are consistent with two coordination ligands per metal because each coordination ligand contributes three contacts across the lattice. Sharing these contacts produces a coordination polymer within each layer; the interlayer Van der Waals force does not add coordination bonds. The index ${\mu }_3$ counts metal centres, whereas a hapticity label would count adjacent coordinated coordination ligand atoms and would not describe this connectivity correctly.^[ref]

The average Pt oxidation state is $+3$, since six bromides balance the two metal atoms. A natural mixed valence assignment is alternating Pt(II), $d^8$, and Pt(IV), $d^6$, rather than two equivalent Pt(III) sites. Use neutral square-planar $\mathrm{P}{\mathrm{t}}^{\mathrm{II}}(\mathrm{N}{\mathrm{H}}_3{)}_2\mathrm{B}{\mathrm{r}}_2$ units and octahedral $\mathrm{P}{\mathrm{t}}^{\mathrm{IV}}(\mathrm{N}{\mathrm{H}}_3{)}_2\mathrm{B}{\mathrm{r}}_4$ units. At every site place two ammonia and two bromide ligands in an equatorial plane; the Pt(IV) sites have two additional axial bromides pointing toward the adjacent Pt(II) sites.

Along the chain the connectivity isEvery Pt–Br–Pt bridge is asymmetric: short to Pt(IV), long to Pt(II). The latter contact is a secondary axial interaction, consistent with the preference of Pt(II) for a square-planar primary coordination sphere. The Pt(IV) site is smaller and more strongly attracts the bridging bromides. A drawing with all axial distances identical would obscure the distinct local environments.

There are four equatorial bromides and two axial bridging bromides per two-Pt repeat, giving precisely $\mathrm{P}{\mathrm{t}}_2(\mathrm{N}{\mathrm{H}}_3{)}_4\mathrm{B}{\mathrm{r}}_6$. A direct Pt–Pt bond is not required. This is a proposed structure consistent with the stated composition and two environments; the formula alone does not determine every equatorial cis/trans arrangement or numerical bond length.

For the usual octahedral Ni(II) hydration-isomer series, distinguish coordinated water from water of crystallization:The first two coordination spheres have no cis/trans choice because they contain zero or one chloride. The last hydration class has two geometrical isomers: the chlorides occupy adjacent or opposite octahedral positions. Thus there are three hydration classes and four structures when cis/trans isomerism is included. Every formula retains two chlorides and six waters overall; the coordination number remains six. The schematic in B6(c) displays the distinct octahedral connectivities. This enumeration states the usual six-coordinate interpretation, rather than treating unspecified changes in coordination number as further members of the same elementary series.