Question

In the uvarovite garnet (Ca₃Cr₂Si₃O₁₂), Ca is in cubic coordination, Cr is in octahedral coordination, and Si is in tetrahedral coordination. The electrostatic bond strength of the Ca²⁺ central ion is ________. (Round off to two decimal places.)

Hint:

EBS = (Charge of cation) / (Coordination number). This helps predict cation-anion stability in silicate structures.

Answer 1

Correct Answer: 0.25

Step 1: Formula used.
Electrostatic bond strength (EBS) \( = \frac{\text{valency}}{\text{coordination number}} \).
Step 2: Given data.
For Ca²⁺, valency = 2, coordination number = 6 (cubic coordination).
Step 3: Substitution.
\[ \text{EBS} = \frac{2}{6} = 0.3333 \] Step 4: Round off.
EBS = 0.33.