Difluorophosphate
Difluorophosphate or difluorodioxophosphate or phosphorodifluoridate is an anion with formula PO2F2−. It has a single negative charge and resembles perchlorate (ClO4−) and monofluorosulfonate(SO3F−) in shape and compounds.[2] These ions are isoelectronic, along withtetrafluoroaluminate.[2][3] It forms a series of compounds. The ion is toxic to mammals as it causes blockage to iodine uptake in the thyroid. However it is degraded in the body over several hours.[2]
Compounds containing difluorophosphate may have it as a simple uninegative ion, it may function as a difluorophosphato ligand where it is covalently bound to one or two metal atoms, or go on to form a networked solid.[4] It may be covalently bound to a non metal or an organic moiety to make an ester or an amide.
Formation[edit]
The ammonium salt of difluorophosphate is formed from reacting phosphorus pentoxide with ammonium fluoride.[2] This was how the ion was first made by its discoverer, Willy Lange, in 1929.[5][3]
Alkali chlorides can react with dry difluorophosphoric acid to form alkali metal salts.[6]
NaCl + HPO2F2 → NaPO2F2 + HCl (gas)
Fluorination of dichlorophosphates can produce difluorophosphates.[7] Another method is fluorination of phosphates or polyphosphates.[5]
Trimethylsilyl difluorophosphate reacts with metal chlorides to make difluorophosphates.[8]
The anhydride phosphoryl difluoride oxide (P2O3F4) can react with oxides such as UO3 to yield difuorophosphates.[9] Phosphoryl difluoride oxide also reacts with alkali fluorides to yield difluorophosphates.[10]
Properties[edit]
In ammonium difluorophosphate the difluorophosphate ion has these interatomic dimensions: P-O length 1.457 Å, P-F length 1.541 Å, O-P-O angle 118.7°, F-P-O 109.4° and F-P-F angle 98.6°. Hydrogen bonding from ammonium to oxygen atoms causes a change to the difluorophosphate ion in the ammonium salt. In potassium difluorophosphate the ion has dimensions: P-O length 1.470 Å, P-F length 1.575 Å, O-P-O angle 122.4°, F-P-O
Compounds containing difluorophosphate may have it as a simple uninegative ion, it may function as a difluorophosphato ligand where it is covalently bound to one or two metal atoms, or go on to form a networked solid.[4] It may be covalently bound to a non metal or an organic moiety to make an ester or an amide.
Formation[edit]
The ammonium salt of difluorophosphate is formed from reacting phosphorus pentoxide with ammonium fluoride.[2] This was how the ion was first made by its discoverer, Willy Lange, in 1929.[5][3]
Alkali chlorides can react with dry difluorophosphoric acid to form alkali metal salts.[6]
NaCl + HPO2F2 → NaPO2F2 + HCl (gas)
Fluorination of dichlorophosphates can produce difluorophosphates.[7] Another method is fluorination of phosphates or polyphosphates.[5]
Trimethylsilyl difluorophosphate reacts with metal chlorides to make difluorophosphates.[8]
The anhydride phosphoryl difluoride oxide (P2O3F4) can react with oxides such as UO3 to yield difuorophosphates.[9] Phosphoryl difluoride oxide also reacts with alkali fluorides to yield difluorophosphates.[10]
Properties[edit]
In ammonium difluorophosphate the difluorophosphate ion has these interatomic dimensions: P-O length 1.457 Å, P-F length 1.541 Å, O-P-O angle 118.7°, F-P-O 109.4° and F-P-F angle 98.6°. Hydrogen bonding from ammonium to oxygen atoms causes a change to the difluorophosphate ion in the ammonium salt. In potassium difluorophosphate the ion has dimensions: P-O length 1.470 Å, P-F length 1.575 Å, O-P-O angle 122.4°, F-P-O