# Question #6fc31

In the solid state of sodium chloride, $N {a}^{+} C {l}^{-}$, each metal cation is surrounded by 6 chloride anions in an octahedral array. And each chloride anion is surrounded by 6 metal cations in an octahedral array. The 1:1 stoichiometry of $N a C l$ makes this a necessity.
However, in solution, the metal cations can be solvated by 4-6 water molecules, to give a so-called ion-dipole complex. That is, while we write $N a C l \left(a q\right)$ or $N {a}^{+}$, the actual species in solution is likely ${\left[N a {\left(O {H}_{2}\right)}_{6}\right]}^{+}$ in which the aqua ligands are quite labile. And likewise the chloride anion is solvated by the positive end of the water dipole, i.e. $\stackrel{{\delta}^{+}}{H} - \stackrel{{\delta}^{-}}{O} - \stackrel{{\delta}^{+}}{H}$.