Сульфат празеодима

Description

Praseodymium sulfate is an average salt of trivalent praseodymium and sulfuric acid, Pr₂(SO₄)₃. The light green color of the crystals corresponds to the f–f transitions of the Pr³⁺ ion. The compound serves as the initial form of praseodymium in inorganic synthesis: oxide and other salts of the element are obtained from it, praseodymium is introduced into the mixture of glasses and ceramic glazes, and is used in the isolation and separation of rare earth elements, since REE sulfates differ in solubility and form double salts with alkali metal sulfates. Synonymous series: sulfuric acid, praseodymium salt (3+); praseodymium sulfate (Pr₂(SO₄)₃); Dipraseodymium trisulfate; praseodymium sesquisulfate; praseodymium sulfate (3+).

Basic Attributes

• CAS No.: 10277-44-8
• Chemical formula on the card: H2O4S 2/3 Pr
• Molecular weight: 588.02
• Exact weight: 587.681
• EU number: 233-622-8
• PSA Specifications: 275.15
• XLogP3: −0.8359

Physico-chemical characteristics

• Appearance: light green crystal
• Density: 3.720 (units not shown on original card)
• Boiling point: 330 °C at 760 mm Hg. Art.
• Steam pressure: 3.35 × 10⁻⁵ mm Hg. Art. at 25 °C

Solubility in water

• 0.1545 ± 0.0019 mol/kg H₂O at 25 °C; the equilibrium phase under these conditions is the octahydrate (data source - RAR88)
• 19.8 g per 100 g H₂O at 0 °C
• 12.6 g per 100 g H₂O at 20 °C
• 0.91 g per 100 g H₂O at 100 °C

Reverse solubility - working feature

The given figures describe a behavior that is rare for salts: with increasing temperature, solubility does not increase, but drops more than twenty times - from 19.8 g at 0 °C to 0.91 g at 100 °C per 100 g of water. This behavior is typical for sulfates of rare earth elements and is directly used in technology: precipitation is carried out by heating the solution rather than cooling, and recrystallization is based on the reverse scheme. The equilibrium solid phase at 25 °C is octahydrate, so the composition of the precipitate depends on the process temperature.

Applications

• feedstock for the production of praseodymium oxide and other compounds of the element
• separation and purification of rare earth elements through differences in sulfate solubility and the formation of double sulfates with alkali metals
• introduction of praseodymium into glass mixture and ceramic glazes
• reagent in analytical chemistry of rare earth elements

Hazard classification

• GHS Warning: H315 (100%) - Causes skin irritation (skin corrosion/irritation)
• Precautions: P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
• Aggregated GHS information provided by 40 companies through 3 notifications to the ECHA C&L registry; one notification may apply to several companies
• Hazard class code according to the previous system: 36/37/38
• Safety instructions: 26, 36
• Tags: Xi (annoying)
• Water hazard class WGK Germany: 3

Storage and handling

Tightly closed container, dry, ventilated room. Class WGK 3 requires that the substance and wash water not enter sewers and water bodies; residues are disposed of according to P501. Work is carried out wearing gloves, safety glasses and special clothing; When pouring and grinding, add respiratory protection in accordance with P261 and P271 - work with sufficient ventilation, do not inhale dust. In case of contact with skin, the effect is P302+P352 (wash with plenty of soap and water), in the eyes - P305+P351+P338.