# Fluoride phosphate

The fluoride phosphates or phosphate fluorides are inorganic double salts that contain both fluoride and phosphate anions. In mineralogy, Hey's Chemical Index of Minerals groups these as 22.1. The Nickel-Strunz grouping is 8.BN.
Related mixed anion compounds are the chloride phosphates, the fluoride arsenates and fluoride vanadates.
They are distinct from the fluorophosphates: monofluorophosphate, difluorophosphate and hexafluorophosphate which have fluorine bonds to the phosphorus.

## Minerals

| name | formula | ratio PO$_4$:F | crystal system | space group | unit cell | volume | density | refractive index |
| Althausite | Mg$_4$(PO$_4$)$_2$(OH,O)(F,☐) | 2:~1 | Orthorhombic | Pnma | a = 8.258 b = 6.054, c = 14.383 | 719.06 | 2.97 | Biaxial (+) n$_α$ = 1.588 n$_β$ = 1.592 n$_γ$ = 1.598 2V: measured: 70° , calculated: 80° Max birefringence: δ = 0.010 |
| Amblygonite | LiAl(PO$_4$)F | 1:1 | Triclinic | P1 | a = 6.644 b = 7.744 c = 6.91 α = 90.35°, β = 117.33°, γ = 91.01° Z=4 | 315.75 | 3.04-3.11 | Biaxial (-) n$_α$ = 1.577 - 1.591 n$_β$ = 1.592 - 1.605 n$_γ$ = 1.596 - 1.613 2V: Measured: 107° to 129.5° Birefringence: 0.020 |
| aravaite | Ba$_2$Ca$_{18}$(SiO$_4$)$_6$(PO$_4$)$_3$(CO$_3$)F$_3$O | 3:3 | trigonal | R3m | a = 7.1255, c = 66.290 Z=3 | 2914.8 | | |
| Arctite | Na$_2$Ca$_4$(PO$_4$)$_3$F | 3:1 | Trigonal | R3m | a = 7.078 c = 41.203 Z=6 | 1,787.64 | 3.13 | Uniaxial (-) n$_ω$ = 1.578 n$_ε$ = 1.577 Birefringence: 0.001 |
| Ariegilatite | BaCa$_{12}$(SiO$_4$)$_4$(PO$_4$)$_2$F$_2$O | | Trigonal | R3m | a = 7.1551 c = 41.303 | 1381.2 | | Uniaxial (-) n$_ω$ = 1.650 n$_ε$ = 1.647 Max Birefringence: δ = 0.003 |
| Babefphite | BaBePO$_4$(F,OH) | 1:~1 | Tetragonal | | | | | Uniaxial (+) n$_ω$ = 1.629 n$_ε$ = 1.632 Max birefringence: δ = 0.003 |
| Belovite-(Ce) | NaCeSr$_3$(PO$_4$)$_3$F | 3:1 | Trigonal | P3 | a = 9.692 c = 7.201 | 585.80 | 4.19 | Uniaxial (-) n$_ω$ = 1.653 - 1.660 n$_ε$ = 1.634 - 1.640 Birefringence: 0.015 |
| Belovite-(La) | NaLaSr$_3$(PO$_4$)$_3$F | 3:1 | Trigonal | P3 | a = 9.647 c = 7.17 | 577.88 | 4.19 | Uniaxial (-) n$_ω$ = 1.653 n$_ε$ = 1.635 - 1.636 Max birefringence: δ = 0.018 |
| Bøggildite | Na$_2$Sr$_2$Al$_2$PO$_4$F$_9$ | 1:9 | Monoclinic | | | | | Biaxial (+) n$_α$ = 1.462 n$_β$ = 1.466 n$_γ$ = 1.469 2V: 80° Max birefringence:δ = 0.007 |
| Carlgieseckeite-(Nd) | NaNdCa$_3$(PO$_4$)$_3$F | | Trigonal | P3 | a = 9.4553 c = 6.9825 | 540.62 | 3.91 | |
| Cloncurryite | Cu$_{0.5}$(VO)$_{0.5}$Al$_2$(PO$_4$)$_2$F$_2$ · 5H$_2$O | 2:2 | Monoclinic | P2$_1$/b | a = 4.9573 b = 12.1824 c = 18.9749 β = 90.933° Z=4 | 1145.78 | 2.525 | Biaxial (-) n$_α$ = 1.548(2) n$_γ$ = 1.550(2) 2V: calculated: 56° Max brefringence: δ = 0.002 |
| Deloneite | (Na$_{0.5}$REE$_{0.25}$Ca$_{0.25}$)(Ca$_{0.75}$REE$_{0.25}$)Sr$_{1.5}$(CaNa$_{0.25}$REE$_{0.25}$)(PO$_4$)$_3$F$_{0.5}$(OH)$_{0.5}$ | | Trigonal | P3 | a = 9.51 c = 7.01 Z=2 | 549.05 | 3.92 | Uniaxial (-) n$_ω$ = 1.682 n$_ε$ = 1.660 Max birefringence: δ = 0.022 |
| Fluellite | Al$_2$(PO$_4$)F$_2$(OH) · 7H$_2$O | | Orthorhombic | Fddd | a = 11.22 b = 21.15 c = 8.54 | 2,027 | 2.139 - 2.17 | Biaxial (+) n$_α$ = 1.473 - 1.490 n$_β$ = 1.490 - 1.496 n$_γ$ = 1.506 - 1.511 Max birefringence: δ = 0.033 |
| Fluorapatite | Ca$_5$(PO$_4$)$_3$F | 3:1 | Hexagonal | P6$_3$/m | a = 9.3973 c = 6.8782 | 526.03 | 3.1-3.25 | Uniaxial (-) n$_ω$ = 1.631 - 1.650 n$_ε$ = 1.627 - 1.646 Birefringence: 0.004 |
| Fluorcaphite | SrCaCa$_3$(PO$_4$)$_3$F | 3:1 | Hexagonal | P6$_3$/m | a = 9.485 c = 7.000 Z=2 | 545.39 | | Uniaxial (-) n$_ω$ = 1.649 n$_ε$ = 1.637 Max birefringence: δ = 0.012 |
| Fluorphosphohedyphane | Ca$_2$Pb$_3$(PO$_4$)$_3$F | 3:1 | Hexagonal | P6$_3$/m | a = 9.640, c = 7.012 Z=2 | 564.4 | 5.445 | Uniaxial (-) n$_ω$ = 1.836 n$_ε$ = 1.824 Max birefringence: δ = 0.012 |
| Fluorstrophite | SrCaSr$_3$(PO$_4$)$_3$F | 3:1 | Hexagonal | P6$_3$/m | a = 9.565 c = 7.115 Z=2 | 563.74 | | Uniaxial (-) n$_ω$ = 1.651 n$_ε$ = 1.637 Max birefringence: δ = 0.014 |
| Francolite | | | | | | | | |
| Herderite | CaBe(PO$_4$)F | | Monoclinic | | a = 4.81, b = 7.7 c = 9.82 β = 90.1° | 363.7 | 3.02 | Biaxial (-) n$_α$ = 1.556 - 1.592 n$_β$ = 1.578 - 1.610 n$_γ$ = 1.589 - 1.620 2V: calculated: 70° Max birefringence: δ = 0.033 |
| Iangreyite | Ca$_2$Al$_7$(PO$_4$)$_2$(PO$_3$OH)$_2$(OH,F)$_{15}$ · 8H$_2$O | 4:~15 | Trigonal | P3 2 1 | a = 6.988 c = 16.707 | 706.5 | | |
| Isokite | CaMg(PO$_4$)F | | Monoclinic | B2/b | a = 6.52 b = 8.75 c = 7.51 β = 121.47° | 365.4 | 3.15-3.27 | Biaxial (+) n$_α$ = 1.590 n$_β$ = 1.595 n$_γ$ = 1.615 2V: ,easured: 51° Max birefringence: δ = 0.025 |
| Kingite | Al$_3$(PO$_4$)$_2$F$_2$(OH) · 7H$_2$O | 2:2 | Triclinic | | a = 9.15 b = 10 c = 7.24 α = 98.6°, β = 93.6°, γ = 93.2° | | | Biaxial |
| Kuannersuite-(Ce) | NaCeBa$_3$(PO$_4$)$_3$F$_{0.5}$Cl$_{0.5}$ | 6:1 | Trigonal | P3 | a = 9.909 c = 7.402 | 629.42 | 4.51 | |
| Lacroixite | NaAl(PO$_4$)F | 1:1 | Monoclinic | B2/b | a = 6.414 b = 8.207 c = 6.885 β = 115.47° | 327.20 | 3.126 - 3.29 | Biaxial (-) n$_α$ = 1.546 n$_β$ = 1.563 n$_γ$ = 1.580 2V: measured: 89° Birefringence: 0.034 |
| Mcauslanite | Fe$_3$Al$_2$(PO$_4$)$_3$(PO$_3$OH)F · 18H$_2$O | 4:1 | Triclinic | | a = 10.05 b = 11.56 c = 6.88 α = 105.84°, β = 93.66°, γ = 106.47° | 728.7 | | Biaxial (-) n$_α$ = 1.522 n$_β$ = 1.531 n$_γ$ = 1.534 2V: measured: 55° to 59.7°, calculated: 58° Max birefringence:δ = 0.012 |
| Minyulite | KAl$_2$(PO$_4$)$_2$(OH,F) · 4H$_2$O | 2:~1 | Orthorhombic | Pba2 | a = 9.34 b = 9.74 c = 5.52 | 502 | 2.47 | Biaxial (+) n$_α$ = 1.531 n$_β$ = 1.534 n$_γ$ = 1.538 2V: measured: 70° , calculated: 82° Max birefringence: δ = 0.007 |
| Miyahisaite | (Sr,Ca)$_2$Ba$_3$(PO$_4$)$_3$F | 3:1 | Hexagonal | P6$_3$/m | a = 9.921, c = 7.469 Z=2 | 636.7 | 4.511 | |
| Morinite | NaCa$_2$Al$_2$(PO$_4$)$_2$(OH)F$_4$ · 2H$_2$O | 2:4 | Monoclinic | | | | 2.94 | Biaxial (-) n$_α$ = 1.551 n$_β$ = 1.563 n$_γ$ = 1.565 2V: measured: 43° , calculated: 44° Max birefringence: δ = 0.014 |
| Nacaphite | Na$_2$Ca(PO$_4$)F | | Monoclinic | P2$_1$/b | a = 13.318 b = 7.0964 c = 10.6490 β = 113.526° Z=8 | 922.81 | | Biaxial (-) n$_α$ = 1.508 n$_β$ = 1.515 n$_γ$ = 1.520 2V: 80° Max birefringence: δ = 0.012 |
| natrophosphate | Na$_7$(PO$_4$)$_2$F.19H$_2$O | 2:1 | Isometric | Fd3c | a = 27.79 Z=56 | 21,461.78 | 1,71-1.72 | Isotropic |
| Nefedovite | Na$_5$Ca$_4$(PO$_4$)$_4$F | 4:1 | Triclinic | | a = 5.4 Å, b = 11.64 Å, c = 16.48 Å α = 134.99°, β = 90.04°, γ = 89.96° | 732.60 | | Biaxial (+) n$_α$ = 1.571 n$_γ$ = 1.590 Max birefringence: δ = 0.019 |
| Nevadaite | (Cu$^{2+}$,Al,V$^{3+}$)$_6$Al$_8$(PO$_4$)$_8$F$_8$(OH)$_2$ · 22H$_2$O | 8:8 | Orthorhombic | P2$_1$mn | a = 12.123 b = 18.999 c = 4.961 | | 2.54 | Biaxial (-) n$_α$ = 1.540 n$_β$ = 1.548 n$_γ$ = 1.553 2V: measured: 76°, calculated: 76° Max birefringence: δ = 0.013 |
| Panasqueiraite | CaMg(PO$_4$)(OH,F) | 1:~1 | monoclinic | | a = 6.53 b = 8.75 c = 6.91 β = 112.33° | 365.2 | 3.27 | Biaxial (+) n$_α$ = 1.590 n$_β$ = 1.596 n$_γ$ = 1.616 2V: measured: 51° , calculated: 58° Max birefringence: δ = 0.026 |
| Richellite | CaFe$^{3+}$$_2$(PO$_4$)$_2$(OH,F)$_2$ | 2:~2 | | | a = 5.18 c = 12.61 | | | |
| Stronadelphite | Sr$_5$(PO$_4$)$_3$F | 3:1 | Hexagonal | P6$_3$/m | a = 9.845 c = 7.383 | 619.72 | | Uniaxial (-) n$_ω$ = 1.630(1) n$_ε$ = 1.623(1) Max birefringence: δ = 0.007 |
| Triplite | Mn$^{2+}$$_2$(PO$_4$)F | 1:1 | Monoclinic | P2$_1$/b | a = 11.9 b = 6.52 c = 10.09 β = 105.62° | 758.4 | 3.9 | Biaxial (+) n$_α$ = 1.650 n$_β$ = 1.660 n$_γ$ = 1.680 2V: measured: 70° to 90°, calculated: 72° Max birefringence: δ = 0.030 |
| Väyrynenite | Mn$^{2+}$Be(PO$_4$)(OH,F) | 1:~1 | Monoclinic | P2$_1$/b | a = 5.411 b = 14.49 c = 4.73 β = 102.75° | 361.71 | 3.22 | Biaxial (-) n$_α$ = 1.638 - 1.640 n$_β$ = 1.658 - 1.662 n$_γ$ = 1.664 - 1.667 2V: measured: 46° to 55°, Calculated: 51° to 57° Max birefringence: δ = 0.026 - 0.027 |
| Viitaniemiite | Na(Ca,Mn$^{2+}$)Al(PO$_4$)(F,OH)$_3$ | 1:~3 | Monoclinic | | a = 6.83 b = 7.14 c = 5.44 β = 109.37° | 250.27 | | Biaxial (-) n$_α$ = 1.557 n$_β$ = 1.565 n$_γ$ = 1.571 2V: measured: 81° , calculated: 80° Max birefringence: δ = 0.014 |
| Wagnerite | (Mg,Fe$^{2+}$)$_2$(PO$_4$)F | 1:1 | Monoclinic | P2$_1$/b | a = 9.645 b = 31.659 c = 11.914 β = 108.26(3)° | 3454.8 | 3.15 | Biaxial (+) n$_α$ = 1.568 n$_β$ = 1.572 n$_γ$ = 1.582 2V: Measured: 25° to 35° ? Birefringence:0.046 Max birefringence: δ = 0.015 |
| Wavellite | Al$_3$(PO$_4$)$_2$(OH,F)$_3$ · 5H$_2$O | 2:~3 | Orthorhombic | | a = 9.621 b = 17.363 c = 6.994 | 1168.3 | 2.36 | Biaxial (+) n$_α$ = 1.518 - 1.535 n$_β$ = 1.524 - 1.543 n$_γ$ = 1.544 - 1.561 2V: measured: 60° to 72°, calculated: 60° to 70° Max birefringence: δ = 0.026 |
| Zwieselite | Fe$^{2+}$$_2$(PO$_4$)F | 1:1 | Monoclinic | P2$_1$/b | | 753.82 | | Biaxial (+) n$_α$ = 1.686 - 1.696 n$_β$ = 1.690 - 1.704 n$_γ$ = 1.703 - 1.713 2V: measured: 58° , calculated: 60° Max birefringence: δ = 0.017 |
| | Na$_{5-4.5}$PO$_4$(CO$_3$,F,Cl) | 1:~1 | | | | | | |

## Artificial

| name | formula | formula weight | crystal system | space group | unit cell Å | volume | density | comment |
| EMM-9; 4-(dimethylamino)pyridine fluoroaluminophosphate | (DMAP)$_2$Al$_4$P$_4$O$_{17}$F$_2$•H$_2$O | | monoclinic | P2$_1$/a | a=14.335 b=13.561 c=14.497 β =101.094° | | | layered |
| | KBPO$_4$F | | monoclinic | Cc | | | | |
| Iron-Doped Sodium–Vanadium Fluorophosphate | Na$_3$V$_{2–y}$O$_{2–y}$Fe$_y$(PO$_4$)$_2$F$_{1+y}$ (y < 0.3) | | tetrahedral | P42/mnm | a=9.0277 c=10.6259 | 866.0 | | |
| | Na$_3$V$_2$O$_{1.6}$(PO$_4$)$_2$F$_{1.4}$ | | | | | | | |
| | Na$_3$V$_2$(PO$_4$)$_2$F$_3$ | | | | | | | |
| | Na$_2$MnPO$_4$F | | | | | | | |
| α | Na$_2$FePO$_4$F | | monoclinic | P2$_1$/c | a = 13.675, b = 5.2503, c = 13.7202, β = 120.230° | | | |
| β | Na$_2$FePO$_4$F | | orthorhombic | | | | | |
| | RbBPO$_4$F | 210.25 | cubic | P2$_1$3 | a=7.5901 Z=4 | 437.26 | 3.194 | colourless |
| MIL-145 | RbGa$_3$(PO$_4$)$_2$(HPO$_4$)F$_4$·C$_5$N$_2$H$_{16}$·2H$_2$O | 3187.11 | monoclinic | P2 | a=14.4314 b=9.1152 c=16.7889 β = 112.708 Z=1 | 2037.30 | 2.598 | colourless |
| | K$_2$SnPO$_4$F$_3$ | 348.86 | monoclinic | P2$_1$/c | a=10.039 b=9.415 c=21.602 beta=95.464 Z=12 | 2032.6 | 3.420 | colourless |
| | K$_6$Sn(P$_2$O$_7$)$_2$F$_2$ | 739.17 | monoclinic | P2$_1$/c | a=8.515 b=12.400 c=8.403 beta=99.58 Z=29 | 874.8 | 2.806 | colourless |
| | K$_2$Sb(P$_2$O$_7$)F | | tetragonal | P4bm | a=8.5239 c=5.572 Z=2 | 404.8 | 3.223 | colourless SHG 4.0×KDP |
| | CsBPO$_4$F | | cubic | P2$_1$3 | a=7.7090 Z=4 | 458.14 | 3.736 | colourless |
| | Na$_2$PrF$_2$(PO$_4$) | | cubic | | | | | |
| | Na$_2$NdF$_2$(PO$_4$) | | cubic | | | | | |
| | Na$_2$SmF$_2$(PO$_4$) | | cubic | | | | | |
| | Na$_2$EuF$_2$(PO$_4$) | | cubic | | | | | |
| | Na$_2$TbF$_2$(PO$_4$) | | cubic | | | | | |
| | Na$_2$PrF$_2$(PO$_4$) | | cubic | | | | | |
| | PbZn(PO$_4$)F | 386.53 | orthorhombic | Pna2$_1$ | a=8.985 b=9.381 c=4.8212 Z=4 | 406.4 | 6.318 | colourless |