Difluorophosphate (original) (raw)

Difluorophosphate or difluorodioxophosphate or phosphorodifluoridate is an anion with formula PO2F−2. It has a single negative charge and resembles perchlorate (ClO−4) and monofluorosulfonate (SO3F−) in shape and compounds.[2] These ions are isoelectronic, along with tetrafluoroaluminate, phosphate, orthosilicate, and sulfate.[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.

The difluorophosphate ion in ammonium difluorophosphate and potassium difluorophosphate has these interatomic dimensions:[11]

Formula

Name

Structure

Infrared spectrum

Melting point

Comments

Reference

LiPO2F2

Lithium difluorophosphate

360 °C

[5][6]

Be(PO2F2)2

Beryllium difluorophosphate

>400 °C d

prepared from BeCl2 and acid

[17]

CH3CH2−O−P(=O)F2

Ethyl difluorophosphate

[18]

[NH4]+PO2F−2

Ammonium difluorophosphate

orthorhombic: a = 8.13 Å, b = 6.43 Å, c = 7·86 Å, Z = 4 space group Pnma

P–F stretching 842 and 860 cm−1; P–O stretching 1138 and 1292 cm−1

213 °C

[NO2]+PO2F−2

Nitronium difluorophosphate

515, 530, 550, 560, 575, 845, 880, 1145, 1300, 2390, 3760 cm−1

nitronium formed from anhydride and N2O5

[19]

[NO]+PO2F−2

Nitrosonium difluorophosphate

500, 840, 880, 1130, 1272, 1315, 2278 cm−1

nitrosonium formed from anhydride and N2O3

[19]

NaPO2F2

Sodium difluorophosphate

210 °C

[6]

Mg(PO2F2)2

Magnesium difluorophosphate

200 °C

[5]

[NH4]+Mg2+(PO2F−2)3

Ammonium magnesium difluorophosphate

_Cmcm a=_5.411 _b_=15.20 _c_=12.68

[20]

Al(PO2F2)3

Aluminium difluorophosphate

polymeric[4]

505, 541, 582, 642, 918, 971, 1200, 1290 cm−1 (with 355 cm−1 impurity)

formed from Al(CH2CH3)3 and acid; colourless insoluble powder[4]

[7][8]

Si(−O−P(=O)F2)4

Silicon(IV) difluorophosphate

formed from SiCl4 and anhydride

[18]

(CH3)3Si−O−P(=O)F2

Trimethylsilyl difluorophosphate

formed from anhydride and [(CH3)3Si]2O

[4][18]

KPO2F2

Potassium difluorophosphate

orthorhombic: a = 8.03 Å, b = 6.205 Å, c = 7.633 Å, Z = 4, V=380.9 Å3, density = 2.44 g/cm3

510, 525, 570, 835, 880, 1145, 1320, 1340 cm−1

263 °C

colourless elongated prisms

[6][11][19][21][22]

(K+)4(PO2F−2)2(S2O2−7)

Tetrapotassium difluorophosphate pyrosulfate

_C_2/c: a = 13.00 Å, b = 7.543 Å, c = 19.01 Å, β = 130.07°, Z = 4

[23]

Ca(PO2F2)2·CH3COOCH2CH3

Calcium difluorophosphate - ethyl acetate 1:1 solvate

[24]

Ca(PO2F2)2

Calcium difluorophosphate

>345 °C d

[5]

[VO2]+PO2F−2

Pervanadyl difluorophosphate

[9]

CrO2(PO2F2)2

Chromyl difluorophosphate

formed from anhydride; red-brown

[25]

Cr(PO2F2)3

Chromium(III) difluorophosphate

320, 385, 490, 575, 905, 955, 1165, 1255 cm−1

formed from excess anhydride, green

[25]

Mn(CO)5PO2F2[_clarification needed_]

184 °C

[26]

HMn(PO2F2)3[_clarification needed_]

dissolve manganese in acid; white

[27]

[NH+4](Mn2+)3(PO2F−2)(PO3F2−)2(F−)2

[28]

Fe(PO2F2)2

Iron(II) difluorophosphate

463, 496, 668 (weak), 869 (double), 1139, 1290 cm−1

180 °C d

colour blue green, hygroscopic, melts 250 °C, above 300 °C starts decomposing to Fe3(PO4)2

[12]

Fe(PO2F2)3

Iron(III) difluorophosphate

262, 493, 528, 570, 914, 965, 1173, 1242 cm−1

>400 °C

decomposes at 230 °C yielding FeF3; dissolve iron in acid in presence of oxygen

[7]

K+(Fe2+)3(PO2F−2)(PO3F2−)2(F−)2

[28]

Co(PO2F2)2

Cobalt(II) difluorophosphate

173 °C

prepared from CoCl2 and acid; pink or blue; blue formed by heating pink to 140 °C

[17]

HCo(PO2F2)3[_clarification needed_]

dissolve cobalt in acid; red-purple

[27]

Co(PO2F2)2·2CH3CN

Cobalt(II) difluorophosphate - methyl cyanide solvate 1:2

orthorhombic: a = 9.227 Å, b = 13.871 Å, c = 9.471 Å, V = 1212 Å3, Z = 4, density = 1.88 g/cm3

treat HCo(PO2F2)3 with CH3CN for a few weeks; red crystals

[29]

[NH+4](Co2+)3(PO2F−2)(PO3F2−)2(F−)2

[28]

Ni(PO2F2)2

Nickel(II) difluorophosphate

255 °C d

slowly prepared from NiCl2 and acid; yellow

[17]

HNi(PO2F2)3[_clarification needed_]

dissolve nickel in acid; yellow

[27]

Cu(PO2F2)2

Copper(II) difluorophosphate

orthorhombic Fddd: a = 10.134 Å, b = 24.49 Å, c = 34.06 Å, Z = 48, V = 8454.3 Å3, density = 2.50 g/cm3

265 °C d

pale blue needles

[5][29]

CuI(xantphos)2(_μ_-PO2F2)

polymeric; monoclinic: a = 12.435 Å, b = 10.887 Å, c = 25.682 Å, β = 100.220°, V = 3421 Å3

colourless

[30]

Zn(PO2F2)2

Zinc(II) difluorophosphate

c. 25 °C?

glassy

[5]

H2[Zn(PO2F2)4]

Tetra(difluorophosphato)zincic(II) acid

Ga(PO2F2)3

Gallium(III) difluorophosphate

[(CH3)2GaPO2F2]2

Dimethylgallium(III) difluorophosphate

dimeric

380, 492, 520, 551, 616, 709, 750, 899, 949, 1171, 1218, 1262, 1295, 1404, 2922, 2982 cm−1

[4][31]

RbPO2F2

Rubidium difluorophosphate

orthorhombic: a = 8.15 Å, b = 6.45 Å, c = 7.79 Å, Z = 4, V = 409.5 Å3 density = 3.02 g/cm3

P–F stretching 827 and 946 cm−1; P–O stretching 1145 and 1320 cm−1

160 °C

white

[6][11][21]

Sr(PO2F2)2

Strontium difluorophosphate

250 °C d

prepared from SrCl2 and acid

[17]

[NH4]Sr(PO2F2)3

Ammonium strontium difluorophosphate

Triclinic _P_1 _a_=7.370 _b_=11.054 _c_=13.645 _α_=88.861 _β_=87.435° _γ_=89.323°

[20]

AgPO2F2

Silver(I) difluorophosphate

[32]

Ag9(PO2F2)14[_clarification needed_]

[28]

Ag(1-methyl-2-alkylthiomethyl-1_H_-benzimidazole)PO2F2

[32]

Ag(2,6-bis-[(2-methylthiophenyl)-2-azaethenyl]pyridine)PO2F2

Triclinic _P_1: a = 7.687 Å, b = 10.740 Å, c = 13.568 Å, α = 99.52°, β = 96.83°, γ = 99.83°, Z = 2, V = 1076 Å3, density = 1.81 g/cm3

[33]

Ag(4,4′-dicyanodiphenylacetylene)PO2F2

Cd(PO2F2)2

Cadmium(II) difluorophosphate

245 °C d

[5]

In(PO2F2)3

Indium(III) difluorophosphate

269, 492, 528, 567, 910, 962, 1179, 1269 cm−1

white, decomposes at 260 °C yielding InF3

[7]

[(CH3)2InPO2F2]2

Dimethylindium(III) difluorophosphate

dimeric

373, 490, 500, 535, 559, 735, 878, 925, 1128, 1179, 1275, 1435, 2928, 3000 cm−1

[31]

SnCl2(PO2F2)2

Tin(IV) dichloride difluorophosphate

[34]

(CH3)2Sn(PO2F2)2

Dimethyltin(IV) difluorophosphate

204 °C d

prepared from (CH3)2SnCl2 and acid; yellow

[17]

(CH3CH2)2Sn(PO2F2)2

Diethyltin(IV) difluorophosphate

262 °C d

prepared from (CH3CH2)2SnCl2 and acid; yellow

[17]

(CH3CH2CH2)2Sn(PO2F2)2

Dipropyltin(IV) difluorophosphate

245 °C d

prepared from (CH3CH2CH2)2SnCl2 and acid; yellow

[17]

(CH3(CH2)3)2Sn(PO2F2)2

Dibutyltin(IV) difluorophosphate

235 °C d

prepared from (CH3(CH2)7)2SnCl2 and acid; yellow

[17]

(CH3(CH2)7)2Sn(PO2F2)2

Dioctyltin(IV) difluorophosphate

114 °C

prepared from (CH3(CH2)7)2SnCl2 and acid; yellow

[17]

SbCl4PO2F2

Antimony(V) tetrachloride difluorophosphate

[34]

SbF4PO2F2

Antimony(V) tetrafluoride difluorophosphate

[34]

(2,2-dipyradyl)2Re(CO)2PO2F2[_clarification needed_]

[35]

Au[bis(triphenylphosphine sulfide-S)]PO2F2[_clarification needed_]

[36]

IO2PO2F2[_clarification needed_]

Raman: 130, 163, 191, 219, 295, 323, 329, 378, 637, 713, 737, 781, 799, 839, 918, 1163 cm−1

yellowish colour, produced from IO3, decomposed by water

[37]

IO3PO2F2[_clarification needed_]

Raman: 217, 247, 269, 305, 343, 367, 395, 473, 569, 643, 671, 717, 797, 891, 1123 cm−1

yellowish colour, produced from H5IO6, decomposed by water

[37]

FXePO2F2

Xenon(II) fluoride difluorophosphate

[38]

Xe(PO2F2)2

Xenon(II) difluorophosphate

[38]

CsPO2F2

Caesium difluorophosphate

orthorhombic: a = 8.437 Å, b = 6.796 Å, c = 8.06 Å, Z = 4, V = 462.1 Å3, density = 3.36 g/cm3

286 °C

[6][11][21]

(Cs+)2(Fe3+)2(PO2F−2)(PO3F2−)2(F−)3

[28]

Ba(PO2F2)2

Barium difluorophosphate

orthorhombic I4_2_d a =10.4935 b =10.4935 c =26.030

>400 °C

[5][20]

[NH4]2Ba(PO2F2)4

Diammonium barium difluorophosphate

_P_2/n a=14.285 b=5.472 c=19.474 β=97.607°

[20]

Re(CO)5PO2F2

[35]

Hg(PO2F2)2

Mercury(II) difluorophosphate

[5]

Hg2(PO2F2)2

Mercury(I) difluorophosphate or di(difluorophosphato)dimercurane

Raman: 220 cm−1

produced from anhydride

[5]

TlPO2F2

Thallium(I) difluorophosphate

produced from anhydride, or acid on TlCl

[5]

[(CH3)2TlPO2F2]2

Dimethylthallium(III) difluorophosphate

dimeric

360, 374, 500, 505, 520, 559, 850, 880, 1120, 1140, 1195, 1250, 1285, 2932, 3020 cm−1

[31]

Pb(PO2F2)2

Lead(II) difluorophosphate

189 °C d

[5]

UO2(PO2F2)2

Uranyl difluorophosphate

260, 498, 854, 924, 980, 1124 cm−1

IR spectrum due to UO2+2

[9]

[(CH3CH2)4N]+PO2F−2

Tetraethylammonium difluorophosphate

[39]

1-ethyl-3-methylimidazolium difluorophosphate

ionic liquid

[40]

1-butyl-3-methylimidazolium difluorophosphate

ionic liquid

[40]

1-butyl-1-methylpyrrolidinium difluorophosphate

ionic liquid

[40]

1-butyl-1-methylpiperidinium difluorophosphate

ionic liquid

[40]

di(3,3′,4,4′-tetramethyl-2,2′,5,5′-tetraselenafulvalenium)difluorophosphate

Transitions to a metallic state below 137 K (−136 °C)

[41]

1,4-diphenyl-3,5-enanilo-4,5-dihydro-1,2,4-triazole (nitron)

monoclinic _P_21/n: a = 7.3811 Å, b = 14.9963 Å, c = 16.922 Å, β = 102.138°, V = 1361.2 Å3, Z = 4

insoluble; yellow-brown

[2][28]

Strychnine PO2F2

[3]

Cocaine PO2F2

[3]

Brucine PO2F2

[3]

Morphine PO2F2

[3]

[N(CH3)4]+PO2F−2

Tetramethylammonium difluorophosphate

[3]

H[B(PO2F2)4]

Tetra(difluorophosphato)boric acid

469, 502, 552, 647, 836, 940, 994, 1093, 1348, 1567 cm−1

formed from BBr3 and acid; liquid

[4]

Li[B(PO2F2)4]

Lithium tetra(difluorophosphato)borate

monoclinic _P_21/c: _a_=7.9074 Å, b = 14.00602 Å, c = 13.7851 Å, β = 121.913°, Z = 4

479, 502, 568, 833, 945, 1002, 1080, 1334 cm−1

formed from HB(PO2F2)4 and butyllithium; colourless

[4]

[HS(CH3)2]+[B(PO2F2)4]−

Dimethylsulfonium tetra(difluorophosphato)borate

472, 511, 555, 648, 832, 933, 993, 1082, 1337, 1436, 2851, 2921, 3042 cm−1

formed from BH3·S(CH3)2 and acid; ionic liquid

[4]

[Li((CH3CH2)2O)+]3[Al(PO2F2)6]−

(Diethyl ether)lithium hexa(difluorophosphato)aluminate

trigonal _R_3: a = 17.4058 Å, b = 17.4058 Å, c = 21.4947 Å, γ = 120°, Z = 6

417, 503, 536, 624, 723, 891, 922, 964, 1174, 1204, 1283 cm−1

formed from butyllithium and triethylaluminium and the acid; white

[4]

K2CrO2(PO2F2)4

305, 370, 485, 550, 870, 920, 1050, 1130, 1250 cm−1

145 °C d

formed from anhydride and K2CrO4; brown

[25]

Na2MoO2(PO2F2)4

amorphous

280, 490, 620, 880, 915, 950, 1020, 1070, 1140, 1280 cm−1

125 °C d

formed from anhydride and K2MoO4; white

[25]

Na2WO2(PO2F2)4

amorphous

280, 474, 620, 930, 1030, 1130, 1230 cm−1

109 °C d

formed from anhydride and K2WO4; white

[25]

This in turn is hydrolysed more to give monofluorophosphoric acid (H2PO3F), and a trace of hexafluorophosphoric acid (HPF6). HPO2F2 also is produced when HF reacts with phosphorus pentoxide. Yet another method involves making difluorphosphoric acid as a side product of calcium fluoride being heated with damp phosphorus pentoxide. A method to make pure difluorphosphoric acid involves heating phosphoryl fluoride with monofluorophosphoric acid and separating the product by distillation:[42]

Difluorophosphoric acid can also be produced by fluorinating phosphorus oxychlorides. P2O3Cl4 and POCl3 react with hydrogen fluoride solution to yield HPO2Cl2 and then HPO2F2.[43] Yet another way is to treat orthophosphate (PO3−4) with fluorosulfuric acid (HSO3F).[44]

Difluorphosphoric acid is a colorless liquid. It melts at −96.5 °C (−141.7 °F) and boils at 115.9 °C (240.6 °F). Its density at 25 °C is 1.583 g/cm3.[14]

Difluorophosphoric acid anhydride also known as phosphoryl difluoride oxide or diphosphoryl tetrafluoride (F2(O=)P−O−P(=O)F2 or P2O3F4) is an anhydride of difluorphosphoric acid. It crystallises in the orthorhombic system, with space group Pcca and Z = 4.[45] P2O3F4 can be made by refluxing difluorophosphoric acid with phosphorus pentoxide. P2O3F4 boils at 71 °C.[46]

Difluorophosphate can form adducts with PF5 and AsF5. In these the oxygen atoms form a donor-acceptor link between the P and As (or P) atoms, linking the difluorides to the pentafluorides. Example salts include KPO2F2·2AsF5, KPO2F2·AsF5, KPO2F2·2PF5 and KPO2F2·PF5.[48]