Product Details
Sodium Metasilicate Pentahydrate, commonly referred to as instant soluble water glass, is an inorganic salt product. It is a non-toxic, odorless and environmentally benign substance presented in the form of white powder or crystalline granules. The compound is freely soluble in water, practically insoluble in ethanol and acidic media, and exhibits hygroscopic characteristics. Its aqueous solution is alkaline, and it is prone to moisture absorption and deliquescence under ambient air conditions.
It is endowed with high detergency efficiency, excellent emulsifying, dispersing, wetting and penetrating properties, as well as distinct pH buffering capability. It can neutralize acidic contaminants, emulsify lipid and oily substances, induce deflocculation of inorganic particulate matters, and demonstrate anti-corrosion performance on metal materials. Among all sodium metasilicate species, sodium metasilicate pentahydrate is the most extensively utilized and typical representative, with its crystalline molecular formula conventionally denoted as Na2SiO3·5H2O
This product possesses the general properties of sodium silicates and sodium metasilicates, and exhibits considerable calcium and magnesium ion sequestration capacity. Notably, its magnesium ion binding capacity is greater than 260 mg MgCO₃/g (under test conditions of 35°C, 20 minutes). By providing superior buffering alkalinity in detergent systems, it imparts corrosion protection for light metals (such as aluminum and zinc), glassware and porcelain. It also enables effective dirt suspension and emulsification, and delivers a certain degree of water softening performance.
Chemical Properties
| Property Item | Standard Specification & Value |
| CAS Number | 10213-79-3 |
| EINECS Code | 229-912-9 |
| Molecular Formula | Na₂SiO₃·5H₂O (H₁₀Na₂O₈Si) |
| Molecular Weight | 212.14 |
| Appearance | White odorless crystalline solid/beads, free-flowing, no caking |
| Melting Point | 72.2 °C (crystal water loss); 1088 °C (anhydrous form) |
| True Density | 2.61 g/cm³ |
| Bulk Density | 0.7-1.0 g/cm³ |
| Refractive Index | 1.52 |
| pH Value (10g/L, 20℃) | 12.5 (strongly alkaline) |
| Water Solubility | 50g/100g water @ 20℃, fully soluble in cold water |
| Other Solubility | Soluble in dilute alkali, insoluble in ethanol and organic acids |
| Chemical Composition (Industrial Grade) | Na₂O: 28.0-30.5%, SiO₂: 27.0-29.2% |
| Stability | Hygroscopic, absorbs moisture/CO₂ in air; non-flammable |
| Core Chemical Features | Excellent decontamination, emulsification, dispersion, pH buffering and metal corrosion inhibition |
| Reactivity | Corrodes metals; reacts violently with strong acids to release silicic acid gel |
| Storage Condition | Room temperature, sealed in dry/ventilated warehouse, below 60℃ |
| Hazard Classification | UN 3253, Class 8 (corrosive), Packing Group III |
Product Application
This substance is extensively deployed in household laundry detergent systems, laundry paste formulations, industrial detergent products, food-grade cleaning agents, metal cleaning solutions, textile finishing processes and paper deinking operations. It acts as an essential functional additive in concentrated detergents, as well as low-phosphate and phosphate-free detergent products. It also finds important application value in the ceramic production and petroleum processing sectors.
It exists in the form of white square crystals or spherical particles, with non-toxic and odorless characteristics. It shows high solubility in water, while exhibiting significant hygroscopicity that leads to deliquescence under atmospheric exposure. It is equipped with integrated properties including detergency, emulsification, dispersion, wetting, permeability and pH buffering. Concentrated aqueous solutions of this compound demonstrate corrosive effects on textile materials and human skin.
