Aluminium fluoride
Anhydrous AlF3
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Names | |
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Other names
Aluminium(III) fluoride
Aluminum trifluoride | |
Identifiers | |
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3D model (
JSmol ) |
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ChEBI | |
ChemSpider | |
ECHA InfoCard
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100.029.137 |
PubChem CID
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RTECS number
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
AlF3 | |
Molar mass |
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Appearance | Colorless to white crystalline solid |
Odor | Odorless |
Density |
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Melting point | 1,290 °C (2,350 °F; 1,560 K)[4] (anhydrous) (sublimes) |
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−13.4×10−6 cm3/mol[2] | |
Refractive index (nD)
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1.3767 (visible range)[3] |
Structure | |
Rhombohedral, hR24
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R3c, No. 167[5] | |
a = 0.49254 nm, c = 1.24477 nm
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Lattice volume (V)
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0.261519 |
Formula units (Z)
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6 |
Thermochemistry | |
Heat capacity (C)
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75.1 J/(mol·K)[6] |
Std molar
entropy (S⦵298) |
66.5 J/(mol·K)[6] |
Std enthalpy of (ΔfH⦵298)formation |
−1510.4 kJ/mol[6] |
Gibbs free energy (ΔfG⦵)
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−1431.1 kJ/mol[6] |
Hazards[7][8][9] | |
GHS labelling: | |
Danger | |
H301, H302, H314, H315, H319, H335, H361, H372 | |
P260, P261, P264, P270, P271, P280, P301+P310, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P330, P332+P313, P337+P313, P362, P363, P403+P233, P405, P501 | |
NFPA 704 (fire diamond) | |
NIOSH (US health exposure limits): | |
PEL (Permissible)
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none |
REL (Recommended)
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2 mg/m3 |
IDLH (Immediate danger) |
N.D. |
Safety data sheet (SDS) | InChem MSDS |
Related compounds | |
Other anions
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Other cations
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Related compounds
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Aluminium fluoride is an
Occurrence and production
Aside from anhydrous AlF3, several hydrates are known. With the formula AlF3·xH2O, these compounds include monohydrate (x = 1), two polymorphs of the trihydrate (x = 3), a hexahydrate (x = 6), and a nonahydrate (x = 9).[10]
The majority of aluminium fluoride is produced by treating
- H2[SiF6] + Al2O3 + 3 H2O → 2 AlF3 + SiO2 + 4 H2O
Alternatively, it is manufactured by thermal decomposition of ammonium hexafluoroaluminate.[12] For small scale laboratory preparations, AlF3 can also be prepared by treating aluminium hydroxide or aluminium with hydrogen fluoride.
Aluminium fluoride trihydrate is found in nature as the rare mineral rosenbergite.
The anhydrous form appears as the relatively recently (as of 2020) recognized mineral óskarssonite.[13][14] A related, exceedingly rare mineral, is zharchikhite, Al(OH)2F.[15][14]
Structure
According to X-ray crystallography, anhydrous AlF3 adopts the rhenium trioxide motif, featuring distorted AlF6 octahedra. Each fluoride is connected to two Al centers. Because of its three-dimensional polymeric structure, AlF3 has a high melting point. The other trihalides of aluminium in the solid state differ, AlCl3 has a layer structure and AlBr3 and AlI3, are molecular dimers.[16][page needed] Also they have low melting points and evaporate readily to give dimers.[17][page needed] In the gas phase aluminium fluoride exists as trigonal molecules of D3h symmetry. The Al–F bond lengths of this gaseous molecule are 163 pm.
Applications
Aluminium fluoride is an important additive for the production of aluminium by electrolysis.[4] Together with cryolite, it lowers the melting point to below 1000 °C and increases the conductivity of the solution. It is into this molten salt that aluminium oxide is dissolved and then electrolyzed to give bulk Al metal.[12]
Aluminium fluoride complexes are used to study the mechanistic aspects of phosphoryl transfer reactions in biology, which are of fundamental importance to cells, as phosphoric acid anhydrides such as adenosine triphosphate and guanosine triphosphate control most of the reactions involved in metabolism, growth and differentiation.[18] The observation that aluminium fluoride can bind to and activate heterotrimeric G proteins has proven to be useful for the study of G protein activation in vivo, for the elucidation of three-dimensional structures of several GTPases, and for understanding the biochemical mechanism of GTP hydrolysis, including the role of GTPase-activating proteins.[19]
Niche uses
Together with
It is also used to inhibit
Like
Safety
The reported oral animal lethal dose (
Many of the
Human exposure to aluminium fluoride can occur in an industrial setting, such as emissions from aluminium reduction processes,[23] or when a person ingests both a fluoride source (e.g., fluoride in drinking water or residue of fluoride-based pesticides) and an aluminium source; sources of human exposure to aluminium include drinking water, tea, food residues, infant formula, aluminium-containing antacids or medications, deodorants, cosmetics, and glassware.[22] Fluoridation chemicals may also contain aluminium fluoride.[24] Data on the potential neurotoxic effects of chronic exposure to the aluminium species existing in water are limited.[25]
See also
References
- ^ ISBN 1-4398-5511-0.
- ISBN 1-4398-5511-0.
- ISBN 9780849304842.
- ^ ISBN 978-0-08-037941-8.
- .
- ^ ISBN 1-4398-5511-0.
- ISBN 9780471726104.
- ^ "Aluminum Fluoride". PubChem. National Institute of Health. Retrieved October 12, 2017.
- ^ NIOSH Pocket Guide to Chemical Hazards. "#0024". National Institute for Occupational Safety and Health (NIOSH).
- .
- .
- ^ ISBN 978-3527306732.
- ^ "Óskarssonite".
- ^ a b "List of Minerals". 21 March 2011.
- ^ "Zharchikhite".
- ISBN 978-0-08-037941-8.
- ISBN 0-12-352651-5..
- S2CID 17666164.
- PMID 9482864.
- ^ "ALUMINUM FLUORIDE, CASRN: 7784-18-1". National Library of Medicine HSDB Database. CDC.gov. June 24, 2005. Retrieved October 12, 2017.
- ^ "ALUMINIUM FLUORIDE (ANHYDROUS) International Chemical Safety Cards (ICSC)". CDC.gov National Institute for Occupational Safety and Health (NIOSH). July 22, 2015. Retrieved July 17, 2017.
- ^ ISBN 978-0-309-10128-8.
- ^ TOXICOLOGICAL PROFILE FOR FLUORIDES, HYDROGEN FLUORIDE, AND FLUORINE (PDF). U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service Agency for Toxic Substances and Disease Registry. 2003. p. 211.
- PMID 24999851.
- ^ Aluminum Compounds Review of Toxicological Literature Abridged Final Report. Prepared for National Institute of Environmental Health Sciences. NTP.gov Nomination Summary for Aluminum contaminants of drinking water (N20025). October 2001