Question

ZnS has two common polymorphs: Sphalerite and Wurtzite. Based on the analysis of Medelung constants alone, predict which polymorph should be more stable. Assume that the Zn-S distances in the two polymorphs are identical.

Answer 1

Answer:

Wurzite has a higher Madelung constant when compared with Sphalerite therefore Wurizite is more stable.

Step-by-step explanation:

Zinc Sulphide is a chemical compound that exhibits polymorphism. This means Zinc Sulphide can exists in different forms as a compound. Zinc Sulphide has two common polymorphs named; Wurtzite and Sphalerite .

This two polymorphs are crystalline in structure. Wurtzite is hexagonal in shape while Sphalerite is cubic in shape.

Madelung constant was named after German Physicist Erwin Madelung. Madelung constant is dependent on the the way ions are arranged in a solid substance or molecule. It is used to calculate the amount of energy required to move an ion from one point to the another in a crystal substance.

Madelung constant for Wurtzite is 1.64132 and for Sphalerite is 1.63806. Due to the fact that Wurtzite has a slightly higher Madelung constant that Sphalerite, it tends to be more stable than Sphalerite.

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