# Borate fluoride

The borate fluorides or fluoroborates are compounds containing borate or complex borate ions along with fluoride ions that form salts with cations such as metals. They are in the broader category of mixed anion compounds. They are not to be confused with tetrafluoroborates (BF$_4$) or the fluorooxoborates which have fluorine bonded to boron.

## Examples

| formula | name | mw | system | space group | unit cell Å | volume Å$^3$ | density | comment |
| Be$_2$(BO$_3$)(OH,F) · H$_2$O | Berborite | | trigonal | P3 | a = 4.434, c = 5.334 | 90.82 | | colourless Uniaxial (-) n$_ω$ = 1.580 n$_ε$ = 1.485 Max birefringence δ = 0.095 |
| γ-Be$_2$BO$_3$F | γ-BBF | 95.83 | trigonal | R32 | a=4.4418 c=19.909 Z=3 | 340.17 | 1.946 | Uniaxial (-) SHG 2.3 × KDP |
| NH$_4$Be$_2$BO$_3$F$_2$ | ABBF | 132.87 | trigonal | R32 | a=4.4398 c=12.4697 Z=3 | 212.87 | 2.243 | Uniaxial (-) n$_o$=1.49389 n$_e$=1.41919 at 636 nm |
| NaBe$_2$BO$_3$F$_2$ | sodium beryllium borate fluoride (NBBF) | | | C2 | a=12.643 b=8.729 c=7.591 β=113.6° | 768 | | double layers of borate rings sandwiching barium atoms. Between pairs of double layers are sodium ions with fluoride. |
| Mg$_2$(BO$_3$)(F,OH) | Pertsevite-(F) | | orthorhombic | Pna2$_1$ | a = 20.49, b = 4.571, c = 11.89 Z=16 | 1,113.6 | | Density 3.12 transparent Biaxial (+) n$_α$ = 1.609 n$_β$ = 1.620 n$_γ$ = 1.642 2V: 65° Max birefringence: δ = 0.033 |
| Mg$_3$(BO$_3$)(F,OH)$_3$ | Fluoborite | | hexagonal | | a = 8.8, c = 3.1 | 208 | | colourless Uniaxial (-) n$_ω$ = 1.570 n$_ε$ = 1.534 Max birefringence δ = 0.036 |
| Mg$_3$(OH)[B(OH)$_4$]$_2$(SO$_4$)F | sulfoborite | | orthorhombic | Pnma | a=10.132 b=12.537 c=7.775 | 987.6 | | Biaxial (-) n$_α$ = 1.527 n$_β$ = 1.536 n$_γ$ = 1.551 2V 79° Max birefringence δ = 0.024 |
| Na$_6$Mg$_3$B$_{10}$O$_{18}$F$_6$ | | | monoclinic | P2$_1$/c | a=13.420 b=6.400 c=10.701 β=90.693° | | | band gap 5.40 eV; birefringence Δn = 0.039 at 1064 nm |
| NaMgBe$_2$(BO$_3$)$_2$F | NMBBF | | | P3c1 | a=4.5408 c=13.439 | | | birefringence 0.081 at 546.1 nm |
| Al$_6$(BO$_3$)$_5$F$_3$ | Jeremejevite | | hexagonal | P6$_3$/m | a = 8.5591, c = 8.1814 | 519 | | density 3.28 Uniaxial (-) n$_ω$ = 1.653 n$_ε$ = 1.640 Max birefringence δ = 0.013 |
| Al$_8$(BO$_3$)$_4$(B$_2$O$_5$)F$_8$ | | 704.7 | tetragonal | P4$_2$/mmc | a=9.134 c=19.112 Z=4 | 1,595 | | density 2.935 colourless |
| Na(Mg$_3$)Al$_6$(Si$_6$O$_{18}$)(BO$_3$)$_3$(OH)$_3$F | Fluor-dravite | | trigonal | R3m | a = 15.955, c = 7.153 Z=3 | 1,577 | | density 3.120 dark brown Uniaxial (-) n$_ω$ = 1.645(2) n$_ε$ = 1.621(2) Max birefringence δ = 0.024 |
| Na(Li$_{1.5}$Al$_{1.5}$)Al$_6$(Si$_6$O$_{18}$)(BO$_3$)$_3$(OH)$_3$F | Fluor-elbaite | | trigonal | R3m | a = 15.8933, c = 7.1222 | 1,558 | | blue green Uniaxial (-) |
| K$_6$B$_{12}$O$_{19}$F$_4$ | | 744.32 | orthorhombic | Pnma | a =15.291 b =7.707 c =8.672 Z=2 | 1022.0 | 2.419 | |
| KBe$_2$BO$_3$F$_2$ | KBBF | | hexagonal | R32 | a=4.427 c=18.744 | 318.3 | 2.40 | Be$_2$BO$_6$F$_2$ rings SHG 1.2 × KDP; UV cutoff 147 nm |
| Ca$_5$(BO$_3$)$_3$F | | | | | | | | |
| Li$_3$CaB$_2$O$_5$F | | 363.04 | orthorhombic | Pnma | a=25.685 b=3.4697 c=5.4404 Z=2 | 484.84 | 2.487 | colourless |
| Li$_5$Ca$_9$(BO$_3$)$_7$F$_2$ | | | | P1 | | | | |
| NaCaBe$_2$B$_2$O$_6$F | | | | | | | | |
| KCaBe$_2$B$_2$O$_6$F | | 467.64 | | P3_1c | a=4.705 c=14.554 Z=2 | 279.1 | 2.783 | |
| Ca(Li$_2$Al)Al$_6$(Si$_6$O$_{18}$)(BO$_3$)$_3$(OH)$_3$F | Fluor-liddicoatite | | trigonal | R3m | a = 15.875, c = 7.126 Z=3 | 1,555 | | density 3.02 Uniaxial (-) n$_ω$ = 1.637 n$_ε$ = 1.621 Max birefringence δ = 0.016 |
| CaMg$_3$(Al$_5$Mg)(Si$_6$O$_{18}$)(BO$_3$)$_3$(OH)$_3$F | Fluor-uvite | | trigonal | R3m | a = 15.954, c = 7.214 Z=3 | 1,590 | | black Uniaxial n$_ω$ = 1.637 - 1.668 n$_ε$ = 1.619 - 1.639 Max birefringence δ = 0.018 - 0.029 |
| KCaBe$_2$B$_2$O$_6$F | | | | | | | | |
| Sc$_2$F$_2$(B$_2$O$_5$) | | 229.54 | orthorhombic | Pbam | a=9.667 b=14.199 c=4.0395 Z=4 | 554.4 | 2.750 | colourless |
| K$_{11}$Sc$_5$(B$_5$O$_{10}$)$_4$F$_6$ | | | orthorhombic | Fdd2 | a 56.769 b 12.207 c 12.6088 | | | transparent to <190 nm |
| Na(Mn$^{2+}$)$_3$Al$_6$(Si$_6$O$_{18}$)(BO$_3$)$_3$(OH)$_3$F | Fluor-tsilaisite | | trigonal | R3m | a = 15.9398, c = 7.1363 | 1,570 | | greenish yellow Uniaxial (-) |
| NaFe$_3$Al$_6$Si$_6$B$_3$O$_{30}$F | | | | | | | | |
| Na(Fe$^{2+}$$_3$)Al$_6$(Si$_6$O$_{18}$)(BO$_3$)$_3$(OH)$_3$F | Fluor-schorl | | trigonal | R3m | a = 16.005, c = 7.176 Z=3 | 1,591.9 | | black Uniaxial (-) n$_ω$ = 1.660 - 1.661 n$_ε$ = 1.636 - 1.637 Max birefringence δ = 0.024 |
| Na(Fe$^{3+}$$_3$)Al$_6$(Si$_6$O$_{18}$)(BO$_3$)$_3$O$_3$F | Fluor-buergerite | | trigonal | R3m | a = 15.8692, c = 7.1882 | 1,568 | | density 3.311 brown Uniaxial (-) n$_ω$ = 1.735 n$_ε$ = 1.655 Birefringence 0.080 |
| Ca(Fe$^{2+}$)$_3$MgAl$_5$(Si$_6$O$_{18}$)(BO$_3$)$_3$(OH)$_3$F | Fluor-feruvite | | | | | | | |
| KCaZn$_2$(BO$_3$)$_2$F | | | | | | | | |
| Li$_6$RbB$_2$O$_6$F | | 263.73 | orthorhombic | Pnma | a=8.41 b=15.96 c=5.08 Z=2 | 682 | 2.568 | |
| RbBe$_2$BO$_3$F$_2$ | RBBF | | Trigonal | R32 | a=4.434 c=19.758 z=3 | | | also contains BeO$_3$F tetrahedra and BO$_3$. It transmits radiation from 180 to 3500 nm. |
| Rb$_{18}$Mg$_6$(B$_5$O$_{10}$)$_3$(B$_7$O$_{14}$)$_2$F | | | monoclinic | C2/c | a=11.06 b=19.70 c=31.01 β=90.13° | | | |
| RbCaBe$_2$B$_2$O$_6$F | | | Trigonal | R32 | | | | |
| KSrBe$_2$B$_2$O$_6$F | | | | | | | | |
| LiSr$_3$Be$_3$B$_3$O$_9$F$_4$ | | | | | | | | |
| NaSr$_3$Be$_3$B$_3$O$_9$F$_4$ | | | | | | | | |
| K$_3$Sr$_3$Li$_2$Al$_4$B$_6$O$_{20}$F | | | | | | | | SHG 4 × KDP; 170 nm UV cutoff |
| Ca(Y,REE,Ca,Na,Mn)$_{15}$Fe$^{2+}$(P,Si)Si$_6$B$_3$O$_{34}$F$_{14}$ | Proshchenkoite-(Y) | | trigonal | R3m | a = 10.7527, c = 27.4002 | 2,743.6 | | brownish |
| (Y,REE,Ca,Na)$_{15}$(Al,Fe$^{3+}$)(Ca$_x$As$^{3+}$$_{1−x}$)(Si,As$^{5+}$)Si$_6$B$_3$(O,F)$_{48}$ | Hundholmenite-(Y) | | trigonal | R3m | a = 10.675, c = 27.02 Z=3 | 2,667 | | density 5.206 brownish Uniaxial (-) |
| (Na,Ca)$_3$(Y,Ce)$_{12}$Si$_6$B$_2$O$_{27}$F$_{14}$ | Okanoganite-(Y) | | trigonal | R3m | a = 10.7108, c = 27.040 | | 4.35 | Tan coloured Uniaxial (-) n$_ω$ = 1.753 n$_ε$ = 1.740 Max birefringence δ = 0.013 |
| ? Y$_5$(SiO$_4$,BO$_4$)$_3$(O,OH,F) | Tritomite-(Y) | | ?hexagonal | | a = 9.32, c = 6.84 | | 3.05-3.4 | isotropic n = 1.627 - 1.685 |
| Cd$_8$B$_5$O$_{15}$F | | 1212.25 | cubic | Fd3m | a = 13.972 Z = 8 | 2,727 | 5.904 | colourless |
| CdZn$_2$KB$_2$O$_6$F | | | | | | | | |
| Li$_3$Cs$_6$Al$_2$B$_{14}$O$_{28}$F | | 1490.58 | orthorhombic | Pnma | a=21.8412 b=19.8875 c=7.1577 Z=4 | 3109.1 | 3.184 | |
| CsBe$_2$BO$_3$F$_2$ | | 247.74 | trigonal | R32 | a=4.4575 c=21.310 Z=3 | 366.7 | 3.366 | colourless |
| Cs$_{18}$Mg$_6$(B$_5$O$_{10}$)$_3$(B$_7$O$_{14}$)$_2$F | | | monoclinic | C2/c | a=11.234 b=20.11 c=32.12 β=90.225° | | | |
| CsCaBe$_2$B$_2$O$_6$F | | | trigonal | R32 | | | | |
| BaBOF$_3$ | | 221.15 | monoclinic | P2$_1$/c | a = 4.620 b = 15.186 c = 4.426 β = 92.045° Z=4 | 310.3 | | contains chains of -OB(F$_2$)- and a double chain of BaF |
| Ba$_5$(BO$_3$)$_3$F | | | | | | | | |
| Li$_2$BaSc(BO$_3$)$_2$F | | 332.80 | hexagonal | P6$_3$/m | a=4.895 c=14.346 | 297.7 | 3.713 | |
| LiBa$_{12}$(BO$_3$)$_7$F$_4$ | | | | I4/mcm | | | | |
| BaBe$_2$BO$_3$F$_3$ | | 271.16 | hexagonal | P6$_3$ | a=7.628 c=13.990 Z=6 | 704.9 | 3.832 | UV cutoff <185 nm; birefringence 0,081 at 200 nm |
| NaBa$_{12}$(BO$_3$)$_7$F$_4$ | | | | I4/mcm | | | | |
| BaMgBe$_2$(BO$_3$)$_2$F$_2$ | BMBBF | 335.283 | trigonal | P3c1 | a=4.5898 c=15.348 | 280.01 | 3.976 | colourless [Be$_2$B$_3$O$_6$F$_2$]$_∞$ |
| Ba$_{3.75}$MgB$_7$O$_{14}$F$_{2.5}$ | | 886.50 | monoclinic | C2/c | a 16.611 b 13.677 c 15.141 β 121.239° Z=8 | 2941.0 | 4.004 | transparent > 203 nm; birefringence 0.081@546 nm |
| BaAl(BO$_3$)F$_2$ | | | hexagonal | P6 | a=4.8879 c=9.403 Z=2 | 194.5 | | UV cutoff 165 nm |
| K$_3$Ba$_3$Li$_2$Al$_4$B$_6$O$_{20}$F | | | | | | | | |
| K$_5$Ba$_{10}$(BO$_3$)$_8$F | | | trigonal | R3c | a = 15.293, c = 22.699 Z = 6 | | | |
| KBa$_7$Mg$_2$B$_{14}$O$_{28}$F$_5$ | | | monoclinic | C2/c | a = 16.638 b = 13.609 c = 15.214 β = 121.309° Z=4 | 2943.3 | 3.934 | colourless |
| BaCaBe$_2$(BO$_3$)$_2$F$_2$ | BCBBF | | trigonal | P3c1 | a=4.6931 c=16.049 | 306.12 | 3.808 | colourless [Be$_2$B$_3$O$_6$F$_2$]$_∞$ |
| Li$_2$BaSc(BO$_3$)$_2$F | | | hexagonal | P6$_3$/m | a=4.895 c=14.346 | | | |
| Ba$_3$Zn(BO$_3$)(B$_2$O$_5$)F | | 656.82 | monoclinic | P2$_1$/c | a = 15.179 b = 7.0064 c = 8.763 β = 100.15° Z=4 | 917.4 | 4.755 | colourless |
| Ba$_4$Zn$_2$(BO$_3$)$_2$(B$_2$O$_5$)F$_2$ | | 937.34 | monoclinic | C2/c | a=20.39 b=4.998 c=13.068 β = 192.59 Z=44 | 1,331 | 4.679 | colourless |
| BaZnBe$_2$(BO$_3$)$_2$F$_2$ | | 376.35 | trigonal | P3 | a = 4.5998, c = 7.7037 Z = 1 | 141.16 | 4.427 | colourless |
| Rb$_3$Ba$_3$Li$_2$Al$_4$B$_6$O$_{20}$F | | | | | | | | |
| BaCdBe$_2$(BO$_3$)$_2$F$_2$ | BDBBF | | | P3c1 | a=4.6808 c=15.788 | | | |
| Ba$_{1.09}$Pb$_{0.91}$Be$_2$(BO$_3$)$_2$F$_2$ | BPBBF | | trigonal | P3m1 | a = 4.7478 c = 8.386, Z = 1 | 163.70 | | UV absorption edge=279.1 nm; birefringence 0.054 at 546.1 nm; 2D [Be$_3$B$_3$O$_6$F$_3$]$_∞$ layer |
| LiBa$_2$Pb(BO$_3$)$_2$F | | | orthorhombic | Pmmn | a=5.487 b=15.96 c=4.034 | | | |
| KNa$_3$Na$_6$Ca$_2$Ba$_6$Mn$_6$(Ti$^{4+}$,Nb)$_6$B$_{12}$Si$_{36}$O$_{114}$(O,OH,F)$_{11}$ | Tienshanite | | hexagonal | P6/m | a = 16.785, c = 10.454 Z=1 | 2,551 | | pale olive green Uniaxial (-) n$_ω$ = 1.666 n$_ε$ = 1.653 Max birefringence δ = 0.013 |
| Ca$_6$(Fe$^{2+}$,Mn$^{2+}$)Y$_3$REE$_7$(SiO$_4$)$_3$(PO$_4$)(B$_3$Si$_3$O$_{18}$)(BO$_3$)F$_{11}$ | Laptevite-(Ce) | | trigonal | R3m | a = 10.804, c = 27.726 Z=3 | 2,803 | | density 4.61 dark brown Uniaxial (-) n$_ω$ = 1.741(3) n$_ε$ = 1.720(3) Max birefringence δ = 0.021 |
| Ba(Y,Ce)$_6$Si$_3$B$_6$O$_{24}$F$_2$ | Cappelenite-(Y) | | trigonal | P3 | a = 10.67, c = 4.68 Z=1 | 461 | 4.407 | greenish brown |
| CaMg[(Ce$_7$Y$_3$)Ca$_5$](SiO$_4$)$_4$(Si$_2$B$_3$AsO$_{18}$)(BO$_3$)F$_{11}$ | Arrheniusite-(Ce) | | trigonal | R3m | a = 10.8082, c = 27.5196 | | | |
| Gd$_4$(BO$_2$)O$_5$F | | | orthorhombic | Pmmn | a=15.746 b=3.8142 c=6.609 Z=2 | 396.9 | 6.45 | colourless |
| Gd$_2$(BO$_3$)F$_3$ | | | | | | | | |
| Gd$_3$(BO$_3$)$_2$F$_3$ | | | | | | | | |
| Gd$_4$[B$_4$O$_{11}$]F$_2$ | | | | | | | | |
| Ba$_2$Gd(BO$_3$)$_2$F | | | orthorhombic | Pnma | a = 7.571 b = 10.424 c = 8.581 Z = 2 | | | |
| Eu$_5$(BO$_3$)$_3$F | | | orthorhombic | Pnma | a=7.225 b=14.124 c=9.859 Z=4 | 1006.1 | 6.306 | yellow |
| TlBe$_2$BO$_3$F$_2$ | | | Trigonal | R32 | a=4.4387 c=19.942 Z=3 | 340.27 | 4.673 | colourless |
| LiBa$_2$Pb(BO$_3$)$_2$F | | | orthorhombic | Pmmn | a=5.487 b=15.97 c=4.034 | 353.4 | 5.887 | colourless |
| (Ca,Ce,La,Th)$_{15}$As$^{5+}$(As$^{3+}$$_{0.5}$,Na$_{0.5}$)Fe$^{3+}$Si$_6$B$_4$O$_{40}$F$_7$ | Vicanite-(Ce) | | trigonal | R3m | a=10.881 c=27.33 | 2,766 | 4.82 | greenish yellow Uniaxial (-) n$_ω$ = 1.757 n$_ε$ = 1.722 Max birefringence δ = 0.035 |