Explain the following :
(i) is a gas whereas is a solid.
(ii) Silicon forms ion whereas corresponding fluoro compound of carbon is not known.
(i) In , sp hybridization occurs, and the carbon atoms overlap to form two sigma bonds while bonding occurs with oxygen. This brings out the linear shape and no dipole energy.
Silicon dioxide is covalent and forms a tetrahedral structure, and each corner is covalent and shares with another tetrahedron.
(ii) The 3d orbitals in silicon are all in the valence shell, and thus the octet expands to give a hybridization. But carbon does not have d-orbitals present in the valence shell. It can only acquire hybridisation. Thus, carbon is unable to form anion.