What type of bonding is present in sand SiO2?

Answer 1

Silica, sand is a giant molecule , each silicon atom is bonded to four oxygen atoms each oxygen is bonded to two silicon atoms. The bonding is covalent and due to the difference in electronegativity (1.54) is polar covalent.

This is very different different from carbon dioxide which is molecular, a gas, where the molecule is linear with pi bonding. One possible explanation is that overlap between the carbon 2p and the oxygen 2p orbitals is better than the overlap between the 3p of silicon and the 2p of oxygen and this favours the giant molecule over the molecular form.

Sand is usually silica "contaminated" with oxides such as iron (III) oxide and is probably better described as a silicate. Pure silica is colourless. Sand varies from the "sandy" colour to black.

The giant molecular structure explains the very high melting point of silica.

Answer 2

In sand, SiO2 molecules are held together by covalent bonding. Covalent bonds form between two nonmetal atoms, like silicon and oxygen in this case, by sharing electrons to achieve a stable electron configuration.

Answer 3

Covalent Bond