Select the correct statement about silicates ?

Options

A. Cyclic silicate having three Si atoms contains six Si-O-Si linkages.
B. `2(1)/2` over oxygen atoms of per tetrahedron unit are shared in double chain silicate
C. `(Si_(2)O_(5))_(n)^(2n-)` is formula of double chain silicate
D. `SiO_(4)^(4-)` units polymerize to form silicate because Si atom has less tendency to formm `pi`-bond with oxygen

Answer

B, D

Explanation

Cyclic silicate having three Si atoms `(Si_(3)O_(7)^(6-))` contains three Si-O-Si linkage.

One tetrahedron shares three oxygen atoms while other shape two oxygenn atoms and these two tetrahedrons constitute one unit. therefore, no . of oxygen atoms shared per tetrahedron or Si atom
`=(3+2)/(2)=2(1)/(2)`
`implies`General formula of double chain silicates: `(Si_(4)O_(11))_(n)^(6n-)`
`implies`As the tendency of formation of multiple bond increases the extent of polymerisation decreases. Silicon has large size hence, it forms less effective `p pi-p pi` overlapping with oxygen.