Answer:

dioxide

Answer	Crossword Clue
DIOXIDE	Compound like silica
DIOXIDE	Dry ice, e.g.
DIOXIDE	Carbon ...

DIOXIDE	Carbon ..
DIOXIDE	Carbon ... (greenhouse gas)
DIOXIDE	Sulfur ... (pungent gas)
DIOXIDE	Carbon attachment
DIOXIDE	Silica or dry ice, e.g.

Crossword

a puzzle consisting of a grid of squares and blanks into which words crossing vertically and horizontally are written according to clues.