Question

Explain:

1. Cyclic silicates 

2. Ino silicates

Answer 1

1. Cyclic silicates: 

Silicates which contain (SiO₃)_n^2n- ions which are formed by linking three or more tetrahedral (SiO₃)^4-_n units cyclically are called cyclic silicates. Each silicate unit shares two of its oxygen atoms with other units. 

Example: Beryl [Be₃Al₂(SiO₃)₆] (an aluminosilicate with each aluminium is surrounded by 6 Structure of Cyclic silicates

2. Ino silicones: 

Silicates which contain V number of silicate units liked by sharing two or more oxygen atoms are called inosilicates. They are further classified as chain silicates and double chain silicates. Chain silicates (or pyroxenes) – These silicates contain (SiO₃)_n^2n- ions formed by linking ‘n’ number of tetrahedral (SiO₃)_n^4- units linearly. Each silicate unit shares two of its oxygen atoms with other Structure of Chain silicates units.

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Example: 

Spodumene – LiAl(SiO₃)₂ Double chain silicates (or amphiboles) – 

These silicates contains [Si₄O₁₁]_n^6n- ions.

In these silicates there are two different types of 

3. Tetrahedra: 

1. Those sharing 3 vertices 

2. Those sharing only 2 vertices.

Examples. 

Asbestos – These are fibrous and noncombustible silicates. Therefore they are used for thermal insulation material, brake linings, construction material and filters. Asbestos being carcinogenic silicates, their applications are restricted.