Neptunium (IV) chloride

Crystal structure
__  Np 4+      __  Cl -
Crystal system	tetragonal
Space group	I 4 1 / amd (No. 141)
Lattice parameters	a = 825 pm c = 746 pm
General
Surname	Neptunium (IV) chloride
other names	Neptunium tetrachloride
Ratio formula	NpCl 4
Brief description	orange-brown solid
External identifiers / databases
CAS number 15597-84-9 Wikidata Q1977880
properties
Molar mass	378.86 g mol −1
Physical state	firmly
density	4.92 g cm −3
Melting point	538 ° C
Hazard and safety information
Radioactive
GHS hazard labeling no classification available
Thermodynamic properties
ΔH f 0	−235.7 kcal mol −1
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Neptunium (IV) chloride is a chemical compound made up of the elements neptunium and chlorine . It has the formula NpCl ₄ and belongs to the class of chlorides .

presentation

Neptunium (IV) chloride was first obtained by reacting neptunium (IV) oxide  (NpO ₂ ) or neptunium (IV) oxalate  (Np (C ₂ O ₄ ) ₂ ) with carbon tetrachloride  (CCl ₄ ) at 500 ° C.

${\displaystyle {\ce {NpO2 + CCl4 -> NpCl4 + CO2}}}$

properties

Physical Properties

Neptunium (IV) chloride is an orange-brown solid that melts at 538 ° C. It crystallizes in the tetragonal crystal system with the lattice parameters a  = 825  pm and c  = 746 pm.

Chemical properties

Neptunium (IV) chloride is sensitive to moisture. Heating in air at 750 ° C leads to neptunium (IV) oxide. It can be reduced to neptunium (III) chloride  (NpCl ₃ ): with hydrogen at 450 ° C and with ammonia gas at 350 to 1000 ° C.

${\displaystyle {\ce {2 NpCl4 + H2 -> 2 NpCl3 + 2 HCl}}}$

It is soluble in organic solvents like acetone and nitromethane .

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 c d e} C. Keller: The chemistry of Neptunium , in: Fortschr. chem. Forsch. , 1969/70 , 13/1 , p. 69.
2. ↑ ^{a b c d e} Gmelin's Handbook of Inorganic Chemistry , System No. 71, Transurane, Part C, pp. 135-136.
3. ^ ^{A b} A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 1969.
4. ↑ 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.

literature

• Zenko Yoshida, Stephen G. Johnson, Takaumi Kimura, John R. Krsul: Neptunium , 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. 699-812 ( doi : 10.1007 / 1-4020-3598-5_6 ).
• C. Keller: The chemistry of neptunium , in: Fortschr. chem. Forsch. , 1969/70 , 13/1 , pp. 1–124 ( doi : 10.1007 / BFb0051170 ).
• DY Choporov, ET Chudinov: Melting point and saturated vapor pressure of neptunium tetrachloride , in: Sov. Radiochem. , 1968 , 10 , pp. 208-213.
• J. Fuger, D. Brown, JF Easey: Thermodynamics of the actinide elements. Part I. Heats of formation of crystalline neptunium tetrachloride, neptunium oxide dichloride, and neptunium trioxide monohydrate, and a new determination of the heat of formation of the Np ^III and Np ^IV ions in 1 M -hydrochloric acid , in: J. Chem. Soc. A , 1969 , pp. 2995-2998 ( doi : 10.1039 / J19690002995 ).