Borax
This substance is composed of white, odorless crystals with alkaline properties. Borax or sodium tetra borate is one of the important constituents of boron, which is a mineral and salt of boric acid. Borax is
 divided into the following three groups based on the number of crystals in their structure:
1- Anhydrous Borax Na2B4O7   
2- Borax Pentahydrate
3- Borax tetrahydrate
But the word Borax is often referred to as Deca hydrate. Borax is easily converted into boric acid and other boron compounds.
Sodium Tetraborate pentahydrate is a white, odorless crystal that has alkaline acidity, can be dissolved in water and some organic solvents. Its molecular formula is Na2B4O7.5H2O.
Borax Deca hydrate or sodium Tetra borate with the chemical formula Na2B4O7.5H2O is form of natural sodium borate consisting of boric acid (B2O3), sodium oxide and water, alkaline, white and crystalline salt with buffer and melting properties, this compound in the form of granular powder or granules is an important source of B2O3, especially in processes that require the simultaneous presence of sodium. 
Uses and applications of Borax:
1- It is used in various laundry and household cleaning products, including enhancers of laundry detergents and washing-up liquid.
2- Sodium borate is used in chemical and biochemical laboratories to make buffers.
3- Water softening agent.
4- Flux: A mixture of Borax and Ammonium Chloride is used as a flux in welding iron and steel, also as a mixture with water as a melt in soldering metals and jewelry such as gold and silver.
5- Small-scale mining: As a substitute for mercury and as a preferred method for gold mining in mining facilities, mining is done on a small scale.
6- Food additives: Borax with the number E285 is used as a food additive in some countries. 
Other uses:
1- Part of combination in enamel glazes.
2- Part of combination of glass, pottery and ceramics.
3- As an additive in ceramic and glaze coating, which improves water resistance and creates an environmentally friendly coating.
4- Fire retardant.
5- Antifungal compound for insulating fiberglass and cellulose.
6- 10% solution for protective wool against willow.
7- The main substance for the production of sodium perborate monohydrate, which is used in detergents, as well as for boric acid and other borates.
8- Part of the adhesive in casein, starch and Dextrin based adhesives.
9- Fluoride detoxification.
10- Ointment for thrush in horse poison.
11- Use in pen ink by dissolving special varnish in heated borax.
12- Snake skin treatment material.
13- Treatment material for salmon eggs, for use in salmon fishing.
14- buffer in swimming pools to control PH.
15- Neutron absorbers used in nuclear reactors and low power fuel ponds to control activity and quench a nuclear chain reaction.
 16- as a nutrient fertilizer for improving and fertility of soil without boron.
17- creating a green monochrome in fireworks.
18- Traditionally used to cover dried meats such as thighs to protect them from bloating during long storage.
19- it is present in some commercial vitamin supplements.
20- blocking the barrier holes of the car and motorcycle radiators.
21- An important composition in glaze.
22- Used by modern blacksmiths in the method of forging furnaces and hammers.