Molybdenum (V) chloride

Crystal structure
General
Surname	Molybdenum (V) chloride
other names	Molybdenum pentachloride
Ratio formula	MoCl 5
Brief description	black solid with a pungent odor
External identifiers / databases
CAS number 10241-05-1 EC number 233-575-3 ECHA InfoCard 100.030.510 PubChem 61497 Wikidata Q2615924
properties
Molar mass	273.21 g mol −1
Physical state	firmly
density	2.928 g cm −3
Melting point	194 ° C
boiling point	268 ° C
Vapor pressure	2.33 hPa (25 ° C)
solubility	decomposes in water with violent reaction
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 314 P: 280-305 + 351 + 338-310
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Molybdenum (V) chloride is an inorganic chemical compound of molybdenum from the group of chlorides .

Extraction and presentation

Molybdenum (V) chloride can be obtained by reacting molybdenum in oxygen-free chlorine . Before the reaction, the metal powder should be heated to high temperatures in a stream of hydrogen or oxygen-free nitrogen to remove any surface oxide. It must then be ensured that before the actual reaction with chlorine, air and moisture are completely removed and kept away from the reaction.

${\displaystyle \mathrm {2\ Mo+5\ Cl_{2}\longrightarrow 2\ MoCl_{5}} }$

It can also be obtained by reacting molybdenum (VI) oxide with carbon tetrachloride under pressure.

properties

Molybdenum (V) chloride is a non-flammable, extremely hygroscopic , blue-black, paramagnetic solid with a pungent odor, which decomposes in water with violent reaction. If it has a dark green color, this is caused by the presence of oxide chlorides . The compound is soluble in water and alcohol (dark green solution) with solvolysis . It is soluble without decomposition in organic solvents such as ether , trichloromethane , carbon tetrachloride (dark red solution), carbon disulfide . Molybdenum (V) chloride has a monoclinic crystal structure with the space group C 2 / m (space group no. 12) , a = 1731 pm, b = 1781 pm, c = 607.9 pm, β = 95.7 °. It does not correspond to that of niobium (V) chloride . In addition to the α-form, three other modifications are also known. The β-form has a triclinic crystal structure with the space group P 1 (No. 2) , the γ-form an orthorhombic crystal structure with the space group Pnma (No. 62) and the δ-form a monoclinic crystal structure with the space group P 2 ₁ / c (No. 14) .

Molybdenum (V) chloride is in solid form as a dimer , whereas in the gaseous state it looks red and is present as a monomer .

use

Molybdenum (V) chloride is used to separate molybdenum.

Individual evidence

1. ↑ ^{a b c d e f g h i} Entry on molybdenum (V) chloride in the GESTIS substance database of the IFA , accessed on August 24, 2016(JavaScript required) .
2. ↑ Data sheet Molybdenum (V) chloride, anhydrous at Sigma-Aldrich , accessed on July 4, 2013 ( PDF ).
3. ↑ ^{a b} Georg Brauer (Ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 1534.
4. ^ AP Hagen: Inorganic Reactions and Methods, The Formation of Bonds to Halogens . John Wiley & Sons, 2009, ISBN 0-470-14539-0 , pp. 171 ( limited preview in Google Book search).
5. ^ ^{A b} Mary Eagleson: Concise Encyclopedia Chemistry . Walter de Gruyter, 1994, ISBN 3-11-011451-8 , p. 662 ( limited preview in Google Book search).
6. ^ J. Beck, F. Wolf: Three New Polymorphic Forms of Molybdenum Pentachloride. In: Acta Crystallographica Section B Structural Science. 53, 1997, pp. 895-903, doi : 10.1107 / S0108768197008331 .
7. ^ Dale L. Perry: Handbook of Inorganic Compounds, Second Edition . Taylor & Francis US, 2011, ISBN 1-4398-1462-7 , pp. 281 ( limited preview in Google Book search).