Chemical properties:

Chemical formula: (Mg,Al)_5Si_8O_20(OH)_2·4H_2O

pH: 8-10 (basic)

Cation exchange capacity: 80-150 meq/100g

Surface area: 120-300 m^2/g

Specific gravity: 2.2-2.6

Physical properties:

Particle size: 1-10 microns

Color: White, gray, yellow, green, or brown

Texture: Soft and fine-grained

Porosity: High

Thermal stability: Stable up to 350°C

The crystal structure of Attapulgite clay consists of layers of tetrahedrons and octahedrons, which are stacked on top of each other. The layers are held together by weak electrostatic forces and hydrogen bonds, which allow for the layers to slide over each other, giving the clay its unique properties.