Question

_________ is not a glass former.

• A. \( \text{SiO}_2 \)
• B. \( \text{B}_2\text{O}_3 \)
• C. \( \text{GeO} \)
• D. \( \text{Cr}_2\text{O}_3 \)

Hint:

Glass formers include SiO\(_2\), B\(_2\)O\(_3\), and GeO\(_2\). Chromium oxide (\( \text{Cr}_2\text{O}_3 \)) is a crystalline refractory material, not a glass former.

Answer 1

The Correct Option is D

Glass formers are compounds that have the ability to form an amorphous glassy structure upon cooling without crystallization. Step 1: Understanding Glass Formers - Silica (\( \text{SiO}_2 \)) is the most common glass former used in traditional glass manufacturing. - Boron trioxide (\( \text{B}_2\text{O}_3 \)) is also a strong glass former, used in borosilicate glasses. - Germanium oxide (\( \text{GeO}_2 \)) is another well-known glass former, similar in structure to silica.

Step 2: Identifying Non-Glass Formers - Chromium oxide (\( \text{Cr}_2\text{O}_3 \)) is not a glass former; it is a refractory oxide that does not form an amorphous structure but rather remains crystalline.

Step 3: Evaluating the Options - Option (A) - Incorrect: Silica (\( \text{SiO}_2 \)) is a well-known glass former. - Option (B) - Incorrect: Boron trioxide (\( \text{B}_2\text{O}_3 \)) is a common glass former. - Option (C) - Incorrect: Germanium oxide (\( \text{GeO}_2 \)) forms glass similar to silica. - Option (D) - Correct: Chromium oxide (\( \text{Cr}_2\text{O}_3 \)) is not a glass former.

Step 4: Conclusion Since Chromium oxide (\( \text{Cr}_2\text{O}_3 \)) does not form glass, the correct answer is option (D).