Sodium Phosphate

Sodium Phosphate Formula

Sodium phosphate is an ionic compound composed of the sodium cation and phosphate anion. This is a salt found both in hydrated and anhydrous salts among which anhydrous(water free) sodium phosphate is more common in nature. Sodium phosphate chemical formula is Na3PO4 and it has a molecular weight of 163.94 g/mol. Beside sodium monophosphate, sodium diphosphate, triphosphate, tetraphosphate and polyphosphates are also found in nature. As it is an ionic compound, it forms crystal structures. It appears as white or off white crystals, granules or may be in the powder form.  It has a density of 2.536 g/cc. Its boiling point is 373 k just like water and melting point is 1856 K.

[Image will be Uploaded Soon]

Structure of Sodium Phosphate

Sodium phosphate is an ionic compound and so exhibits electrovalent chemical structure. The phosphate anion itself consists of a covalent structure. Sodium atoms have a total of 11 electrons of which one is in its outermost shell as sodium is an alkali metal. Sodium readily expels the outermost electron to produce sodium cation. Three Na+ and one PO43- get attracted to each other by means of electrostatic force of attraction and sodium phosphate molecule is generated. 

[Image will be Uploaded Soon]

Different Types of Sodium Phosphate

Although trisodium monophosphate(Na3PO4)is much more common, besides this many types of sodium phosphates are found. These are disodium phosphate or disodium hydrogen phosphate, monosodium phosphate or sodium dihydrogen phosphate, disodium pyrophosphate, tetrasodium pyrophosphate which have the molecular formulae of Na2HPO4, NaH2PO4, Na2H2P2O7 and Na4P2O7 respectively.

[Images will be Uploaded Soon]

Trisodium phosphate is prepared in the laboratory by a simple reaction of sodium hydroxide or caustic soda with phosphoric acid. Three molecules of sodium hydroxide are neutralized with tribasic orthophosphoric acid (H3PO4) to produce trisodium phosphate salt and water.

H3PO4 + 3NaOH → Na3PO4+ 3H2O

Disodium phosphate is industrially prepared by the action of dicalcium phosphate on sodium bisulfate. Disodium pyrophosphate is prepared by the thermal decomposition of monosodium phosphate.

Uses of Sodium Phosphate in Industry

The most common sodium phosphate, trisodium monophosphate is mostly used as detergents, soaps, and fertilizers. It acts as preservatives in the processing of animals’ foods. Trisodium phosphate along with disodium and monosodium phosphate are used mostly as food additives. They are used as emulsifiers in processed cheese in the dairy industry. It is also used as a thickening agent in the bakery industry. Disodium pyrophosphate is used as a buffer. Besides, it is used in processing of canned seafood in order to maintain their taste and colour. It is also used in lather industries to get rid of stains from hides. Tetrasodium pyrophosphate is also used in the processing of canned foods as food additive and preservative. Tetrasodium pyrophosphate has a unique quality of removing magnesium from saliva so that it can reduce the accumulation of dental plaques and cavities. So this compound is uniquely used among phosphates in toothpaste. 

Adverse Effects of the Use of Phosphates in Industry

Phosphates are mostly responsible for eutrophication of water. It is a process by which water bodies receive excess phosphates that stimulate increased algal growth, called an algal bloom. It ultimately leads to the decomposition of algae so that the oxygen content of the water gets reduced. Phosphates used as detergents and soaps are mainly responsible for eutrophication as they are washed off and mixed in ponds, rivers, or lakes. For this reason, the usage of phosphates as detergent or fertilizers becomes limited. 

Medicinal Uses of Phosphates

Sometimes phosphates are used in the preparation of medicines of constipation that is used to clear the bowels off but the usage of phosphate in medicine industries is not safe. Phosphates can increase the risk of kidney problems in case of application of high dosage. This symptom is referred to as the medical terminology phosphate nephropathy. So their use in high dosage is not safe at all.

Sodium Tripolyphosphate

Sodium polyphosphate has the molecular formula Na5P3O10. It has a molecular mass of 367.86 g/mol. It is prepared by heating the mixture of sodium dihydrogen phosphate and disodium hydrogen phosphate. These two get condensed, remove water, and produce sodium tripolyphosphate. 

Did you know

  • Sodium phosphate is mostly made from the phosphate rocks of mine.

  • Consumption of regular and long term dosage of sodium phosphate becomes unhealthy for health.

  • Although sodium phosphate is thought to be safe by FDA(Food and Drug Administration) in processed foods where it is used as preservatives, patients of kidney disease should avoid foods containing sodium phosphate.

  • Consumption of high dosage of sodium phosphate causes reduced bone density, kidney problems, heart disease and even early death.

  • When sodium phosphate is consumed by mixing with other phosphates, it will help to fortify phosphorus in the body.

  • Meats, beans, lentils and nuts are good sources of phosphates.

  •  Phosphate can increase the growth of algae 500 times of its normal growth in a water body. 

  • Graham’s salt, Kurrol’s salt, and Madrell’s salt are the derivatives of polyphosphate. 

  • Oral sodium phosphate should not be used as laxative under 5 years’ children.

FAQ (Frequently Asked Questions)

1. What is Oral Sodium Phosphate?

Oral sodium phosphate is an oral medicine that is used as a medicine of constipation. It helps to clear the bowels off so it is used as laxative. It is mainly used before colonoscopy in which clearing of the bowes from the colon is required. Oral sodium phosphate(OSP) is used for clinical trials to check the proper dosage of administration so that there is minimum risk for kidney problems.

2. Are Phosphates Necessary for Human Health or Not?

Phosphorus is a macronutrient in the animal body. It is an essential part of nucleic acids, cell membranes, phospholipids, signal transduction molecules. It has important roles in formation of bones and teeth. It has important metabolic roles. It is very important for photosynthesis in plants. So phosphate is very essential for humans, animals and plants.