Preparation, properties and uses of phosphine

Preparation

(i) From Phosphide

By the reaction of phosphides with water.

formation of phosphine from calcium phosphide
formation of phospine from sodium phosphide

Aluminium phosphide is decomposed with dilute sulphuric acid.

formation of phospine from Aluminium phosphide

(ii) From Phosphorus acid

Phosphorus acid decomposes when heated to give a pure sample of phosphine.

formation of phospine form phosphorus acid

Structure

Phosphine has the following electronic structure.

Structure of phosphine

Structure of phosphine

The electronic structure of phosphine is similar to ammonia in that it has a pyramidal structure. The bond angle H-P-H, however, is = 93o (e.g., NH3 =107o)

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