Carbon dioxide is a gas at room temperature & silicon(IV) oxide is a solid with a high melting point. Explain, these observations in terms of ..the structure & bonding of both substances.

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hnystrom eNotes educator| Certified Educator

The carbon dioxide molecule is a molecule that is perfectly symmetric about its axes.  There is a carbon atom in the center with oxygen atoms at either side.  It has no dipole moment so it electrically neutral.  It does not bond easily with other CO2 molecules hence it is a gas.  Silicon dioxide molecules tend to link up into tetrahedral structures with oxygen atoms linking up neighboring silicon atoms.  This produces a strong crystal structure that repeats endlessly.