Answer:
[tex]K2O[/tex]
Explanation:
If you use a melting point periodic table there is a listing of all the elements and their melting point.
Potassium (K) has a melting point of 63.25 degrees Celsius and oxygen (O) has a melting point of -218 degrees Celsius. Therefore, if you add those two values up
[tex](63.25x2)+-218 = -91.5 Degrees Celsius[/tex]
All the other compounds do not reach negatives.
