Curium (III) chloride

Crystal structure
__ Cm 3+      __ Cl -
Crystal system	hexagonal
Space group	P 6 3 / m (No. 176)
Lattice parameters	a = 726 pm c = 414 pm
Coordination numbers	Cm [9], Cl [3]
General
Surname	Curium (III) chloride
other names	Curium trichloride
Ratio formula	CmCl 3
Brief description	colorless solid
External identifiers / databases
CAS number 13537-20-7 Wikidata Q1144605
properties
Molar mass	depending on the isotope: 344–358 g · mol −1
Physical state	firmly
Melting point	695 ° C
Hazard and safety information
Radioactive
GHS hazard labeling no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Curium (III) chloride is a curium salt of hydrochloric acid and therefore belongs to the class of chlorides . It is a colorless, crystalline solid with the chemical formula CmCl ₃ . Since there are no stable isotopes of the element curium , the compound is radioactive . Since there are no natural deposits of curium, this compound can only be synthesized.

presentation

Curium (III) chloride can be produced from the reaction of curium (III) oxide or curium (III) hypochlorite with anhydrous hydrogen chloride at 400–600 ° C.

${\displaystyle {\ce {Cm2O3 + 6 HCl ->[\Delta T] 2 CmCl3 + 3 H2O}}}$

properties

Curium (III) chloride is a colorless and poorly water-soluble ionic compound consisting of Cm ³⁺ and Cl ^- ions. It crystallizes in the hexagonal crystal system in the space group P 6 ₃ / m (space group no. 176) with the lattice parameters a  = 726  pm and c  = 414 pm and two formula units per unit cell . Its crystal structure is isotype with uranium (III) chloride . In the structure, the curium atoms are each surrounded by nine chlorine atoms, resulting in a coordination polyhedron that is a triple-capped, trigonal prism . The Cm – Cl bond lengths are 260 and 291 pm. The melting point of the compound is 695 ° C.

use

Curium (III) chloride is used in actinide research. The salt can serve as a starting compound for the production of curium (III) complexes with chloro ligands .

safety instructions

Classifications according to the CLP regulation are not available because they only include chemical hazard and play a completely subordinate role compared to the hazards based on radioactivity . The latter also only applies if the amount of substance involved is relevant.

Individual evidence

1. ↑ ^{a b} Gregg J. Lumetta, Major C. Thompson, Robert A. Penneman, P. Gary Eller: Curium , in: Lester R. Morss, Norman M. Edelstein, Jean Fuger (ed.): The Chemistry of the actinides and Transactinide Elements , Springer, Dordrecht 2006; ISBN 1-4020-3555-1 , pp. 1397-1443 ( doi : 10.1007 / 1-4020-3598-5_9 ).
2. ↑ JR Peterson, JH Burns: Single Crystal and Powder Diffraction Studies of Curium-248 Trichloride, ²⁴⁸ CmCl ₃ , in: J. Inorg. Nucl. Chem. , 1973 , 35  (5), pp. 1525-1530 ( doi: 10.1016 / 0022-1902 (73) 80241-6 ).
3. ↑ The hazards emanating from radioactivity do not belong to the properties to be classified according to the GHS labeling. With regard to other hazards, this substance has either not yet been classified or a reliable and citable source has not yet been found.
4. ↑ JC Wallmann, J. Fuger, JR Peterson, JL Green: Crystal Structure and Lattice parameter of curium trichloride , in: J. Inorg. Nucl. Chem. , 1967 , 29  (11), pp. 2745-2751 ( doi: 10.1016 / 0022-1902 (67) 80013-7 ).
5. ^ V. Milman, B. Winkler, CJ Pickard: Crystal structures of curium compounds: an ab initio study , in: Journal of Nuclear Materials , 2003 , 322  (2-3), pp. 165-179 ( doi: 10.1016 / S0022 -3115 (03) 00321-0 ).

literature

• Gregg J. Lumetta, Major C. Thompson, Robert A. Penneman, P. Gary Eller: Curium , in: Lester R. Morss, Norman M. Edelstein, Jean Fuger (Eds.): The Chemistry of the Actinide and Transactinide Elements , Springer, Dordrecht 2006; ISBN 1-4020-3555-1 , pp. 1397-1443 ( doi : 10.1007 / 1-4020-3598-5_9 ).