If a trivalent atom replaces a few silicon atoms in three dimensional network of silicon dioxide, what would be the type of charge on overall structure ?

If a trivalent atom replaces a few silicon atoms in three dimensional

1.	If a trivalent atom replaces a few silicon atoms in three dimensional network of silicon dioxide, what would be the type of charge on overall structure ?
Answer» SOLUTION :In `SiO_2` STRUCTURE , if a trivalent ATOM replaces Si atom, then holes are created . These holes will make the crystal, The crystals as whole are ELECTRICALLY neutral. In the following arrangement , when silicon atom is substituted by trivalent atom, then there is increase in positive charge by approximately one. This increase in positive charge makes the crystal conductor.