Which of the following is an incorrect match?

• A
  Permutit $\to$ Hydrated silicates of $Na$ and $Al$
• B
  Calgon $\to$ Sodium hexametaphosphate
• C
  $BeH_2, MgH_2 \to$ Covalent polymeric hydride
• D
  Hydrolith $\to$ Electron deficient hydride