Phosphoric Acid（industrial grade) CAS#7664-38-2
Phosphoric acid, also known as orthophosphoric acid (molecular formula H₃PO₄), occurs in its pure state as either colorless, clear viscous liquid or orthorhombic crystals. It is odorless yet has a strong sour taste. The commercially‑available 85‑percent grade presents as a colorless or lightly‑tinted syrupy liquid. It features a melting point of 42.35 °C and a specific gravity of 1.70. As a high‑boiling‑point acid, it is fully miscible with water in all proportions. Upon heating to 213 °C, it loses half of its molecular water and converts into pyrophosphoric acid. Further heating up to 300 °C triggers transformation to metaphosphoric acid. Its relative vapor density is 1.834. This inorganic acid dissolves readily in both water and ethanol.
Phosphoric Acid Chemical Properties
| Melting point | ~40 °C(lit.) |
| Boiling point | 158 °C(lit.) |
| density | 1.685 g/mL at 25 °C(lit.) |
| vapor density | 3.4 (vs air) |
| vapor pressure | 2.2 mm Hg ( 20 °C) |
| refractive index | n20/D 1.433 |
| FEMA | 2900 | PHOSPHORIC ACID |
| storage temp. | no restrictions. |
| solubility | H2O: soluble |
| pka | 2.1-7.2-12.3(at 25℃) |
| form | Solid or Viscous Liquid |
| Specific Gravity | 1.7 |
| color | ≤10(APHA) |
| PH | 3.06(1 mM solution);2.26(10 mM solution);1.63(100 mM solution); |
| Odor | Odorless |
| PH Range | 1.5 |
| biological source | synthetic |
| Water Solubility | MISCIBLE |
| λmax | λ: 260 nm Amax: ≤0.05 λ: 280 nm Amax: ≤0.04 |
| Merck | 14,7344 |
| BRN | 1921286 |
| Exposure limits | TLV-TWA 1 mg/m3 (ACGIH, MSHA, and OSHA); TLV-STEL 3 mg/m3 (ACGIH). |
| Dielectric constant | 61.0 |
| InChIKey | NBIIXXVUZAFLBC-UHFFFAOYSA-N |
| LogP | -2.15 |
| CAS DataBase Reference | 7664-38-2(CAS DataBase Reference) |
| NIST Chemistry Reference | Phosphoric acid(7664-38-2) |
| EPA Substance Registry System | Phosphoric acid (7664-38-2) |
