Borax, Borax Decahydrate, Sodium Tetraborate Decahydrate, Sodium Borate, Sodium Tetraborate Pentahydrate, 1303-96-4, 12179-04-3

Borax, Borax Decahydrate, Sodium Tetraborate Decahydrate, Sodium Borate, Sodium Tetraborate Pentahydrate, 1303-96-4, 12179-04-3

BORAX (Sodium Tetraborate Decahydrate)

1. PRODUCT DEFINITION AND CHEMICAL IDENTITY

Note: The term borax refers to several closely related forms depending on water of crystallisation:

• Decahydrate (10 mol water): Na₂B₄O₇·10H₂O / CAS 1303-96-4 (most common commercial form)

• Pentahydrate (5 mol water): Na₂B₄O₇·5H₂O / CAS 12179-04-3

• Anhydrous: Na₂B₄O₇ / CAS 1330-43-4

2. PHYSICAL AND CHEMICAL PROPERTIES

3. FUNCTIONAL PROPERTIES

• Buffering: Provides a mildly alkaline pH (~9.2) in aqueous solution; combined with boric acid, forms buffer systems across a wide pH range.

• Cleaning / Stain removal: Helps disperse grease and dirt in water; boosts laundry detergent performance.

• Disinfectant / Antifungal: Effective against mould, mildew, fungi, and bacteria.

• Flux: Dissolves metal oxides during soldering, brazing, and welding, cleaning the metal surface.

• Fire retardant: Releases water vapour when heated, delaying ignition and slowing flame spread.

• Neutron absorber: Used in nuclear reactors and spent fuel pools to control chain reactions.

• Micronutrient fertiliser: Supplies boron to deficient agricultural soils.

4. ALTERNATIVE NAMES AND SYNONYMS

• Borax

• Sodium borate

• Sodium tetraborate decahydrate

• Disodium tetraborate decahydrate

• Sodium pyroborate decahydrate

• Tincal / Tincar (natural mineral name)

• Boric acid, disodium salt, decahydrate

• Commercial names: 20 Mule Team Borax, Solubor, Three Elephant, Gerstley borate, Boricin, Dominant, Fullbor W6364

5. BORAX FORM VARIANTS AND COMPARISON

6. SECTORAL APPLICATIONS, USAGE RATES, AND EXAMPLE FORMULATIONS

Example Formulations:

• All-Purpose Household Cleaner (Spray):

  • Borax: 2–3 g

  • White vinegar (5%): 50 mL

  • Water: 500 mL

  • Optional: a few drops of lemon or tea tree oil
    Mix in a spray bottle; use on kitchen counters and bathroom surfaces.

• Laundry Detergent Booster:

  • Borax (powder): 1 part

  • Washing soda (sodium carbonate): 1 part

  • Grated bar soap: 1 part
    Add 2–3 tablespoons per laundry load.

• Cockroach Control Bait:

  • Borax: 10%

  • Powdered sugar: 45%

  • Flour: 45%
    Place in small shallow trays in dry areas. Keep away from children and pets.

• Metal Soldering Flux (Jeweller's Type):

  • Borax: 40 g

  • Ammonium chloride: 30 g

  • Water: 50 mL (to form a paste)
    Apply a thin layer to the workpiece during soldering.

7. ALTERNATIVES AND COMPARISON

8. REGULATORY STATUS, SAFETY, AND ENVIRONMENT

• GHS Classification (CLP Regulation):

  • Signal word: Danger

  • Hazard statements:

    • H360FD: May damage fertility. May damage the unborn child.

  • Precautionary statements: P201, P202, P280, P308+P313, P405, P501.

• Food additive (E285): Historically used in some foods, but now banned as a food additive in most countries. Ingestion carries health risks.

• Cosmetic use: The EU Cosmetics Regulation restricts boron compounds. Borax-containing cosmetics are only permitted in specific categories and at defined limits.

• Environmental impact: Soluble in water and can reach groundwater. Harmful to plants and aquatic life at high concentrations. Avoid discharge into drains.

• Storage: Keep tightly sealed in a cool, dry, well-ventilated area. Protect from high humidity. Keep separate from food and feedstuffs.

• Personal protection: Avoid breathing dust; wear gloves and safety goggles. Keep out of reach of children and pets.

9. TOXICOLOGICAL PROFILE (Summary)

10. FREQUENTLY ASKED QUESTIONS

Q1. Are borax and boric acid the same?
No. Borax is sodium tetraborate, while boric acid (H₃BO₃) is a weak acid. Borax can be converted to boric acid by reacting with hydrochloric acid: Na₂B₄O₇·10H₂O + 2 HCl → 4 H₃BO₃ + 2 NaCl + 5 H₂O

Q2. Where is borax found as a natural mineral?
It occurs naturally in arid and semi-arid regions, in dry lake beds. Major deposits are found in Turkey (Kırka/Eskişehir, Bandırma/Balıkesir, Bigadiç), the USA (California), Romania, and Argentina. Turkey holds approximately 72% of the world's boron reserves.

Q3. What is the difference between decahydrate and pentahydrate?
Decahydrate contains 10 moles of water of crystallisation per formula unit; pentahydrate contains 5 moles. Pentahydrate provides a higher B₂O₃ content and lower transport costs. Decahydrate is more common in household and retail products.

Q4. How is borax used in making slime?
A small amount of borax (e.g., 1 teaspoon) is dissolved in warm water (1 cup) and mixed with PVA glue. The borate ions crosslink the polymer chains, forming the stretchy, sticky slime structure. Children should use it under supervision; excessive amounts may cause skin irritation.

Q5. What can I use instead of borax for household cleaning?
Washing soda (sodium carbonate) and baking soda (sodium bicarbonate) are good alternatives for most cleaning applications. They are considered safer and more environmentally friendly.

Q6. What is the shelf life of borax?
Under proper conditions (tightly sealed, dry environment), it can be stored for more than 24 months. If exposed to air, surface efflorescence may occur; this does not significantly affect quality.

11. QUICK REFERENCE TABLE