Drywall compound, also known as joint compound or mud, is a type of paste used to fill in gaps and joints between drywall panels. It is typically made from a combination of gypsum plaster, water, and various other additives, such as binders, extenders, and setting agents. The specific composition can vary depending on the manufacturer and the intended application.

Here are the common components found in drywall compound:

1. Gypsum Plaster: The primary component of drywall compound is gypsum plaster, which is a soft sulfate mineral composed of calcium sulfate dihydrate (CaSO4·2H2O). It provides strength, hardness, and fire resistance to the compound.

2. Water: Water is used to hydrate the gypsum plaster and form a workable paste. The amount of water used affects the consistency and setting time of the compound.

3. Adhesives/Binders: Adhesives or binders are added to improve the adhesion and cohesion of the compound. These can include materials like polyvinyl acetate (PVA), methylcellulose, starch, or natural gums.

4. Extenders: Extenders are inert materials added to enhance certain properties of the compound. Common extenders include talc, clay, limestone, or silica. They help regulate the compound's consistency, texture, and workability.

5. Setting Agents or Retarders: Setting agents or retarders are used to control the drying time of the compound. They can be accelerators, which speed up the drying process, or retarders, which slow it down.

6. Additives: Various additives may be added to improve specific properties of the drywall compound. These can include antifungal agents to prevent mold growth, lightweight fillers to reduce density, or polymers to enhance flexibility.

It's important to note that the exact formulation of drywall compound can vary between manufacturers and specific products, so it's always advisable to refer to the product specifications or manufacturer's guidelines before use.