= Solution
Each trisilanol cage loses its three hydroxyl protons and supplies a \b[facial tridentate <silanolate ligand> of charge $3-$]. Two such <coordination ligands> replace all six chlorides of <tungsten>(VI), giving
$$
\boxed{\mathrm{W}\{\mathrm{Cy_7Si_7O_9(O)_3}\}_2}
$$
with approximately octahedral $\mathrm{WO_6}$ coordination. <tungsten> remains $+6$, is $d^0$, and is bound to six <oxygen> donors, three from each cage. The six liberated protons combine with the six chlorides to give six HCl; no W=O bond or <tungsten> reduction is needed. The <molecular formula> is $\mathrm{C_{84}H_{154}Si_{14}O_{24}W}$. This bis(cage) <tungsten> structure was directly prepared and characterized in the primary literature.<Preparation and Characterization of a Bis(silsesquioxane)tungsten Complex by Peter Smet and others>[Inorganic Chemistry 37, 6583–6586: synthesis from tungsten hexachloride and the cyclohexyl-substituted trisilanol]{ref}
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