Arsenic pentachloride
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IUPAC name
arsenic pentachloride
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Other names
arsenic(v) chloride
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Identifiers | |
3D model (
JSmol ) |
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PubChem CID
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CompTox Dashboard (EPA)
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Properties | |
AsCl5 | |
Molar mass | 252.1866 g/mol |
Melting point | −50 °C (−58 °F; 223 K) |
Hazards | |
GHS labelling: | |
Danger | |
H280, H350, H361, H370, H372 | |
P201, P202, P260, P264, P270, P281, P307+P311, P308+P313, P314, P321, P405, P410+P403, P501 | |
NIOSH (US health exposure limits): | |
PEL (Permissible)
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[1910.1018] TWA 0.010 mg/m3[1] |
REL (Recommended)
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Ca C 0.002 mg/m3 [15-minute][1] |
IDLH (Immediate danger) |
Ca [5 mg/m3 (as As)][1] |
Structure | |
Trigonal Bipyramidal (D3h) | |
Related compounds | |
Related group 5 chlorides
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Phosphorus pentachloride Antimony pentachloride |
Related compounds
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Arsenic pentafluoride Arsenic trichloride Arsenic pentoxide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Arsenic pentachloride is a
trigonal bipyramidal
structure where the equatorial bonds are shorter than the axial bonds (As-Cleq = 210.6 pm, 211.9 pm; As-Clax= 220.7 pm).
The pentachlorides of the elements above and below arsenic in group 15, phosphorus pentachloride and antimony pentachloride are much more stable and the instability of AsCl5 appears anomalous. The cause is believed to be due to incomplete shielding of the nucleus in the 4p elements following the first transition series (i.e. gallium, germanium, arsenic, selenium, bromine, and krypton) which leads to stabilisation of their 4s electrons making them less available for bonding. This effect has been termed the d-block contraction and is similar to the f-block contraction normally termed the lanthanide contraction.
References
- ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0038". National Institute for Occupational Safety and Health (NIOSH).
- ISBN 978-0-08-037941-8.
- .
- ^ Haupt S, Seppelt K (2002). "Solid State Structures of AsCl5 and SbCl5". Zeitschrift für anorganische und allgemeine Chemie. 628 (4): 729–734. .