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| Names | |||
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| IUPAC name Praseodymium(III) chloride | |||
| Other names Praseodymium chloride; praseodymium trichloride | |||
| Identifiers | |||
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3D model (JSmol) |
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| ChemSpider | |||
| ECHA InfoCard | 100.030.710 | ||
| EC Number |
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| UNII | |||
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| Properties | |||
| PrCl3 | |||
| Molar mass | 247.24 g/mol (anhydrous) 373.77 g/mol (heptahydrate) | ||
| Appearance | blue-green solid (anhydrous) light green solid (heptahydrate) | ||
| Density | 4.02 g/cm3 (anhydrous) 2.250 g/cm3 (heptahydrate) | ||
| Melting point | 786 °C (1,447 °F; 1,059 K) | ||
| Boiling point | 1,710 °C (3,110 °F; 1,980 K) | ||
| 104.0 g/100 ml (13 °C) | |||
| +44.5·10−6 cm3/mol | |||
| Structure | |||
| hexagonal (UCl3 type),hP8 | |||
| P63/m, No. 176 | |||
| Tricapped trigonal prismatic (nine-coordinate) | |||
| Hazards | |||
| Occupational safety and health (OHS/OSH): | |||
Main hazards | Irritant | ||
| Related compounds | |||
Otheranions | Praseodymium(III) oxide,Praseodymium(III) fluoride Praseodymium bromide praseodymium iodide | ||
Othercations | Cerium(III) chloride Neodymium(III) chloride | ||
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |||
Praseodymium(III) chloride is theinorganic compound with theformulaPrCl3. Like otherlanthanide trichlorides, it exists both in the anhydrous and hydrated forms. It is a blue-green solid that rapidly absorbs water on exposure to moist air to form a light green heptahydrate.
Praseodymium(III) chloride is prepared by treating praseodymium metal withhydrogen chloride:[1][2]
It is usually purified by vacuum sublimation.[3]
Hydrated salts of praseodymium(III) chloride can be prepared by treatment of either praseodymium metal or praseodymium(III) carbonate withhydrochloric acid:
PrCl3∙7H2O is a hygroscopic substance, that will not crystallize from themother liquor unless it is left to dry in a desiccator. Anhydrous PrCl3 can be made by thermal dehydration of the hydrate at 400 °C in the presence ofammonium chloride, the so-calledammonium chloride route.[3][4][5] Alternatively the hydrate can be dehydrated usingthionyl chloride.[3][6]
Praseodymium(III) chloride isLewis acidic, classified as "hard" according to theHSAB concept. Rapid heating of thehydrate may cause small amounts ofhydrolysis.[3] PrCl3 forms a stable Lewis acid-base complex K2PrCl5 by reaction withpotassium chloride; this compound shows interestingoptical andmagnetic properties.[1]
Aqueous solutions of praseodymium(III) chloride can be used to prepare insoluble praseodymium(III) compounds. For example, praseodymium(III) phosphate and praseodymium(III) fluoride can be prepared by reaction withpotassium phosphate andsodium fluoride, respectively:
When heated with alkali metal chlorides, it forms a series of ternary (compounds containing three different elements) materials with the formulae MPr2Cl7, M3PrCl6, M2PrCl5, and M3Pr2Cl9 where M = K, Rb, Cs.[7]
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