A carbonate fluoride, fluoride carbonate, fluorocarbonate or fluocarbonate is a double salt containing both carbonate and fluoride. The salts are usually insoluble in water, and can have more than one kind of metal cation to make more complex compounds. Rare-earth fluorocarbonates are particularly important as ore minerals for the light rare-earth elements lanthanum, cerium and neodymium. Bastnäsite is the most important source of these elements. Other artificial compounds are under investigation as non-linear optical materials and for transparency in the ultraviolet, with effects over a dozen times greater than Potassium dideuterium phosphate. [1]
Related to this there are also chlorocarbonates and bromocarbonates. Along with these fluorocarbonates form the larger family of halocarbonates. In turn halocarbonates are a part of mixed anion materials. Compounds where fluorine connects to carbon making acids are unstable, fluoroformic acid decomposes to carbon dioxide and hydrogen fluoride, and trifluoromethyl alcohol also breaks up at room temperature. Trifluoromethoxide compounds exist but react with water to yield carbonyl fluoride.
MI | MII | MIII | Charge | CO3 | F |
---|---|---|---|---|---|
3 | 3 | 1 | 1 | ||
1 | |||||
1 | 1 | ||||
1 | 1 | 4 | 1 | 2 | |
2 | |||||
2 | 1 | 5 | 2 | 1 | |
1 | 1 | 1 | 3 | ||
1 | 2 | ||||
3 | 1 | 6 | 2 | 2 | |
4 | 1 | 7 | 3 | 1 | |
2 | 3 | ||||
2 | 1 | 1 | 5 | ||
1 | 2 | 8 | 3 | 2 | |
3 | 1 | 9 | 1 | 7 | |
3 | 2 | 12 | 5 | 2 | |
2 | 3 | 13 | 5 | 3 |
The structure of the carbonate fluorides is mainly determined by the carbonate anion, as it is the biggest component. The overall structure depends on the ratio of carbonate to everything else, i.e. number (metals and fluorides)/number of carbonates. For ratios from 1.2 to 1.5 the carbonates are in a flat dense arrangement. From 1.5 to 2.3 the orientation is edge on. From 2.5 to 3.3 the arrangement is flat open. With a ratio from 4 to 11, the carbonate arrangement is flat-lacunar. [2]
The simplest formula is LnCO3F, where Ln has a 3+ charge.
For monocations there is A3CO3F, where A is a large ion such as K, Rb or Tl. [2]
For M = alkali metal, and Ln = lanthanide: MLnCO3F2 1:1:1:2; M3Ln(CO3)2F2 3:1:2:2; M2Ln(CO3)2F 2:1:2:1; M4Ln(CO3)2F3·H2O 4:1:2:3; M4Ln2(CO3)3F4 2:3:3:4. [2] M2Ln(CO3)F2 2:1:1:3.
For B = alkaline earth and Ln = lanthanide (a triple-charged ion) BLn(CO3)2F 1:1:2:1; BLn2(CO3)3F2 1:2:3:2 B2Ln3(CO3)5F3 2:3:5:3; B2Ln(CO3)2F3 2:1:2:3; B2Ln(CO3)F5 2:1:1:5 B2Ln(CO3)3F 2:1:3:1; B3Ln(CO3)F7 3:1:1:7; B3Ln2(CO3)5F2 3:2:5:2. [2]
For alkali with dication combinations: MB: MBCO3F MB3(CO3)2F3·H2O. [2]
For dications A and B there is ABCO3F2 with a degenerate case of A = B. [2]
KPb2(CO3)2F is layered. Each layer is like a sandwich, with lead and carbonate in the outer sublayers, and potassium and fluoride in the inner layer. K2.70Pb5.15(CO3)5F3 extends this structure with some of the layers also being a double-decker sandwich of carbonate, fluoride, carbonate, fluoride, carbonate. [3]
In the rare-earth fluorocarbonates the environment for the rare-earth atoms is 9-coordinated. Six oxygen atoms from carbonate are at the apices of a trigonal prism, and fluoride ions cap the rectangular faces of the prism. [4]
Carbonate fluoride compounds can be formed by a variety of related methods involving heating the precursor ingredients with or without water. Thallous fluoride carbonate was made simply by evaporating a fluoride thallium solution in ethanol and water in air. It absorbed sufficient carbon dioxide to yield the product. Most other carbonate fluorides are very insoluble and need high-temperature water to crystallise from. Supercritical water heated between 350 and 750 °C under pressures around 200 bars can be used. A sealed platinum tube can withstand the heat and pressure. Crystallisation takes about a day. With subcritical water around 200 °C, crystallisation takes about 2 days. This can happen in a teflon-coated pressure autoclave. The starting ingredients can be rare-earth fluorides and alkali carbonates. The high pressure is needed to keep the water liquid and the carbon dioxide under control, otherwise it would escape. If the fluoride levels are low, hydroxide can substitute for the fluoride. Solid-state reactions require even higher temperatures. [2]
Bastnäsite along with lukechangite (and petersenite) can be precipitated from a mixed solution of CeCl3, NaF, and NaOH with carbon dioxide. [5] Another way to make the simple rare-earth fluorocarbonates is to precipitate a rare-earth carbonate from a nitrate solution with ammonium bicarbonate and then add fluoride ions with hydrofluoric acid (HF). [6]
Pb2(CO3)F2 can be made by boiling a water solution of lead nitrate, sodium fluoride and potassium carbonate in a 2:2:1 molar ratio. [7]
structure | carbonate vibration, cm−1 | |||
---|---|---|---|---|
ν1 | ν2 | ν3 | ν4 | |
bastnäsite | 1086 | 868 | 1443 | 728 |
synchysite | ||||
parisite | 1079 1088 | 870 | 1449 | 734 746 |
KCdCO3F | 853 | 1432 | ||
RbCdCO3F | 843 | 1442 |
The visible spectrum of fluorocarbonates is determined mainly by the cations contained. Different structures only have slight effect on the absorption spectrum of rare-earth elements. [4] The visible spectrum of the rare-earth fluorocarbonates is almost entirely due to narrow absorption bands from neodymium. [4] In the near infrared around 1000 nm there are some absorption lines due to samarium and around 1547 nm are some absorption features due to praseodymium. Deeper into the infrared, bastnäsite has carbonate absorption lines at 2243, 2312 and 2324 nm. Parisite only has a very weak carbonate absorption at 2324 nm, and synchysite absorbs at 2337 nm. [4]
The infrared spectrum due to vibration of carbon–oxygen bonds in carbonate is affected by how many kinds of position there are for the carbonate ions. [4]
An important chemical reaction used to prepare rare-earth elements from their ores, is to roast concentrated rare-earth fluorocarbonates with sulfuric acid at about 200 °C. This is then leached with water. This process liberates carbon dioxide and hydrofluoric acid and yields rare-earth sulfates:
Subsequent processing precipitates a double sulfate with sodium sulfate at about 50 °C. The aim is to separate out the rare-earth elements from calcium, aluminium, iron and thorium. [8]
At high enough temperatures the carbonate fluorides lose carbon dioxide, e.g.
at 340 °C. [2]
The processing of bastnäsite is important, as it is the most commonly mined cerium mineral. When heated in air or oxygen at over 500 °C, bastnäsite oxidises and loses volatiles to form ceria (CeO2). Lukechangite also oxidises to ceria and sodium fluoride (NaF). Ce7O12 results when heated to over 1000 °C. [5]
At 1300 °C Na2CO3 loses CO2, and between 1300 and 1600 °C NaF and Na2O boil off. [5]
When other rare-earth carbonate fluorides are heated, they lose carbon dioxide and form an oxyfluoride:
In some rare-earth extraction processes, the roasted ore is then extracted with hydrochloric acid to dissolve rare earths apart from cerium. Cerium is dissolved if the pH is under 0, and thorium is dissolved if it is under 2. [10]
KCdCO3F when heated yields cadmium oxide (CdO) and potassium fluoride (KF). [11]
When lanthanum fluorocarbonate is heated in a hydrogen sulfide, or carbon disulfide vapour around 500 °C, lanthanum fluorosulfide forms:
Note that this also works for other lanthanides apart from cerium.
When lanthanum carbonate fluoride is heated at 1000 °C with alumina, lanthanum aluminate is produced: [13]
Within the hot part of the Earth's crust, rare-earth fluorocarbonates should react with apatite to form monazite. [14]
Some rare-earth fluorocarbonate minerals exist. They make up most of the economic ores for light rare-earth elements (LREE). These probably result from hydrothermal liquids from granite that contained fluoride. [15] Rare-earth fluorocarbonate minerals can form in bauxite on carbonate rocks, as rare-earth fluoride complexes react with carbonate. [16] Carbonate fluoride compounds of rare-earth elements also occur in carbonatites. [17]
name | formula | pattern | formula weight | crystal system | space group | unit cell | volume | density | comment | references |
---|---|---|---|---|---|---|---|---|---|---|
albrechtschraufite | MgCa4(UO2)2(CO3)6F2⋅17–18H2O | 0:7:0:14:6:2 | triclinic | P1 | a = 13.569, b = 13.419, c = 11.622 Å, α = 115.82, β = 107.61, γ = 92.84° Z= | 1774.6 | 2.69 | [18] | ||
aravaite | Ba2Ca18(SiO4)6(PO4)3(CO3)F3O | trigonal | R3m | a = 7.1255, c = 66.290 Z=3 | 2914.8 | [19] | ||||
arisite-(Ce) | NaCe2(CO3)2[(CO3)1–xF2x]F | P6̅m2 | a=5.1109 c=8.6713 Z=1 | 196.16 | 4.126 | dissolves in dilute HCl | [20] | |||
barentsite | Na7AlH2(CO3)4F4 | 9:0:1:12:4:4 | 505.95 | P1 | a=6.472 b=6.735 c=8.806 92.50 β=97.33 119.32 | |||||
Bastnäsite | (Ce, La)CO3F | 0:0:1:2:1:1 | P62m | a=7.094 c=4.859 | ||||||
Bastnäsite-(La) | La(CO3)F | 0:0:1:2:1:1 | 217.91 | P62c | ||||||
Bastnäsite-(Nd) | Nd(CO3)F | 0:0:1:2:1:1 | 223.25 | |||||||
Brenkite | Ca2(CO3)F2 | 0:2:0:4:1:1 | 178.16 | orthorhombic | Pbcn | a=7.650 b=7.550 c=6.548 | [2] | |||
Cebaite | Ba3(Nd,Ce)2(CO3)5F2 | 0:3:2:12:5:2 | Monoclinic | a=21.42 b=5.087 c=13.30 β=94.8° | [2] [21] | |||||
Cordylite = Baiyuneboite | NaBaCe2(CO3)4F | 1:1:2:9:4:1 | 699.58 | P63/mmc | a=5.1011 c=23.096 | [2] | ||||
Doverite | CaY(CO3)2F | 0:1:1:5:2:1 | 268.00 | [22] | ||||||
Francolite | ||||||||||
Horvathite-Y (horváthite) | NaY(CO3)F2 | 1:0:1:4:1:2 | 209.90 | Pmcn | a=6.959 b=9.170 c=6.301 | [23] | ||||
Huanghoite-(Ce) | BaCe(CO3)2F | 0:1:1:5:2:1 | 416.46 | Trigonal | R3m | a=5.072 c=38.46 | [21] [2] | |||
Kettnerite | CaBi(CO3)OF | |||||||||
kukharenkoite-(Ce) | Ba2Ce(CO3)3F | 0:2:1:7:3:1 | 613.80 | P21/m | a=13.365 b=5.097 c=6.638 β=106.45 | [2] | ||||
Lukechangite-(Ce) | Na3Ce2(CO3)4F | 3:0:2:9:4:1 | 608.24 | P63/mmc | a=5.0612 c=22.820 | |||||
lusernaite | Y4Al(CO3)2(OH,F)11.6H2O | 0:0:5:15:2:11 | Orthorhombic | Pmna | a=7.8412 b=11.0313 c=11.3870 Z=2 | 984.96 | ||||
Mineevite-(Y) | Na25BaY2(CO3)11(HCO3)4(SO4)2F2Cl | 2059.62 | [24] | |||||||
Montroyalite | Sr4Al8(CO3)3(OH,F)26.10-11H2O | [25] | ||||||||
Parisite | [LaF]2Ca(CO3)3 | 0:1:2:8:3:2 | 535.91 | Rhombohedral | R3 | a=7.124 c=84.1 | ||||
Parisite-(Ce) | [CeF]2Ca(CO3)3 | 0:1:2:8:3:2 | 538.33 | monoclinic | Cc | a = 12.305 Å, b = 7.1056 Å, c = 28.2478 Å; β = 98.246°; Z = 12 | ||||
Podlesnoite | BaCa2(CO3)2F2 | 0:3:0:6:2:2 | 375.50 | Orthorhombic | Cmcm | a = 12.511 b=5.857 c=9.446 Z=4 | 692.2 | 3.614 | named after Aleksandr Semenovich Podlesnyi 1948 | [26] |
qaqarssukite-(Ce) | BaCe(CO3)2F | 0:1:1:5:2:1 | 416.46 | [2] | ||||||
röntgenite-(Ce) | Ca2Ce3(CO3)5F3 | 0:2:3:13:5:3 | 857.54 | R3 | a=7.131 c=69.40 | [2] | ||||
rouvilleite | Na3Ca2(CO3)3F | 3:2:0:7:3:1 | 348.15 | Cc | a=8.012 b=15.79 c=7.019 β =100.78 | [2] | ||||
Schröckingerite | NaCa3(UO2)(CO3)3F(SO4)·10H2O | 1:6:13:3:1+ | 888.49 | also with sulfate | ||||||
Sheldrickite | NaCa3(CO3)2F3·(H2O) | 1:3:0:7:2:3 | 338.25 | Trigonal | a = 6.726 Å; c = 15.05 Å Z = 3 | 2.86 | [27] | |||
stenonite | Sr2Al(CO3)F5 | 0:2:1:7:1:5 | 357.22 | P21/n | a=5.450 b=8.704 c=13.150 β=98.72 | [2] | ||||
Synchysite | Ca(Ce,La)(CO3)2F | 0:1:1:5:2:1 | C2/c | a=12.329 b=7.110 c=18.741 β=102.68 | [2] | |||||
Thorbastnäsite | CaTh(CO3)2F2.3H2O | P6̅2c | a = 6.99, c = 9.71 z=3 | 410.87 | brown | [28] | ||||
zhonghuacerite | Ba2Ce(CO3)3F | 0:2:1:7:3:1 | 613.80 | Monoclinic | [29] |
These are non-linear optical crystals in the AMCO3F family KSrCO3F KCaCO3F RbSrCO3F KCdCO3F CsPbCO3F RbPbCO3F RbMgCO3F KMgCO3F RbCdCO3F CsSrCO3F RbCaCO3F KZnCO3F CsCaCO3F RbZnCO3F [30]
formula | name | weight | crystal | space group | unit cell | volume | density | UV | thermal stability | properties | reference |
---|---|---|---|---|---|---|---|---|---|---|---|
g/mol | Å | Å3 | nm | °C | |||||||
K2(HCO3)F·H2O | Dipotassium hydrogencarbonate fluoride monohydrate | 176.24 | monoclinic | P 21/m | a=5.4228 b=7.1572 c=7.4539 β=105.12 Z=2 | 279.28 | 2.096 | transparent below 195 nm | [31] | ||
K3(CO3)F | 196.30 | R3c | a=7.4181 c=16.3918 | [2] | |||||||
KLi2CO3F | 131.99 | Hexagonal | P63222 | a=4.8222 c=10.034 Z=2 | 202.06 | 2.169 | 190 | SHG; transparent | [32] | ||
KMgCO3F | 142.42 | Hexagonal | P62m | a=8.8437 c=3.9254 z=3 | 265.88 | 2.668 | 200 | [33] | |||
Na3Ca2(CO3)3F | rouvilleite | 348.16 | monoclinic | Cm | a=8.0892 b=15.900 c=3.5273 β=101.66 Z=2 | 444.32 | 2.602 | 190 | white | [34] | |
KCaCO3F | 158.18 | Hexagonal | P6m2 | a=5.10098 c=4.45608 Z=1 | 100.413 | 2.616 | ≤320 °C | [35] | |||
KCaCO3F | 158.18 | Hexagonal | P62m | a=9.1477 c=4.4169 Z=3 | 320.09 | 2.462 | ≥320 °C | [35] | |||
KMnCO3F | 173.04 | Hexagonal | P6c2 | a=5.11895 c=8.42020 Z=2 | 191.080 | 3.008 | [35] | ||||
KCuCO3F | 181.65 | [36] | |||||||||
NaZnCO3F | 167.37 | hexagonal | P62c | a=8.4461 c=15.550 Z=12 | 960.7 | 3.472 | [37] | ||||
Na3Zn2(CO3)3F | 398.74 | monoclinic | C2/c | a=14.609 b=8.5274 c=20.1877 β=102.426 Z=12 | 2456.0 | 3.235 | 213 | 200 | [38] | ||
KZnCO3F | 183.48 | hexagonal | P62c | a=5.0182 c=8.355 Z=2 | 182.21 | 3.344 | colourless | [39] | |||
Rb3(CO3)F | 335.41 | R3c | a=7.761 c=17.412 | [2] | |||||||
RbCaCO3F | 204.56 | hexagonal | P62m | a=9.1979 c=4.4463 Z=3 | 325.77 | 3.128 | [40] | ||||
RbMgCO3F | 188.79 | Hexagonal | P62m | a=9.0160 c=3.9403 z=3 | 277.39 | 3.39 | colourless | ||||
RbZnCO3F | 229.85 | hexagonal | P62c | a=5.1035 c=8.619 Z=2 | 194.4 | 3.926 | white | [39] | |||
KRb2(CO3)F | 289.04 | R3c | a=7.6462 c=17.1364 | [2] | |||||||
K2Rb(CO3)F | 242.67 | R3c | a=7.5225 c=16.7690 | [2] | |||||||
KSrCO3F | 205.73 | hexagonal | P62m | a=5.2598 c=4.696 Z=1 | 112.50 | 3.037 | [40] | ||||
RbSrCO3F | 252.10 | hexagonal | P62m | a=5.3000 c=4.7900 Z=6 | 116.53 | 3.137 | [40] | ||||
KCdCO3F | 230.51 | Hexagonal | P6̅m2 | a=5.1324 c=4.4324 z=1 | 101.11 | 3.786 | 227 | 320 | colourless | [41] | |
RbCdCO3F | 276.88 | hexagonal | P6̅m2 | 1=5.2101 c=4.5293 z=1 | 106.48 | 350 | colourless | [11] | |||
Li2RbCd(CO3)2F | hexagonal | P63/m | a=4.915 c=15.45 Z=2, | 323.3 | colourless | [42] | |||||
Cs9Mg6(CO3)8F5 | 1917.13 | Orthorhombic | Pmn21 | a=13.289 b=6.8258 c=18.824 z=2 | 1707.4 | 3.729 | 208 | [33] | |||
CsCaCO3F | 252.00 | hexagonal | P62m | a=9.92999 c=4.5400 Z=3 | 340.05 | 3.692 | [40] | ||||
CsSrCO3F | 230.51 | Hexagonal | P6̅m2 | a=9.6286 c=4.7482 Z=3 | 381.2 | <200 | 590 | [43] | |||
KBa2(CO3)2F | 452.8 | trigonal | R3 | a=10.119 c=18.60 Z=9 | 1648 | 4.106 | colourless | [44] | |||
Ba3Sc(CO3)F7 | 649.91 | Orthorhombic | Cmcm | a=11.519 b=13.456 c=5.974 Z=4 | 926.0 | 4.662 | colourless | [45] | |||
BaMnCO3F2 | 290.27 | Hexagonal | P63/m | a=4.9120, c=9.919 Z=2 | [46] [47] | ||||||
BaCoCO3F2 | 294.27 | [48] | |||||||||
Ba2Co(CO3)2F2 | 491.60 | Orthorhombic | Pbca | a=6.6226, b=11.494, c=9.021 and Z=4 | 686.7 | [49] | |||||
BaNiCO3F2 | 294.03 | [48] | |||||||||
BaCuCO3F2 | 298.88 | Cmcm | a=4.889 b=8.539 c=9.588 | [46] | |||||||
BaZnCO3F2 | 300.72 | Hexagonal | P63/m | a=4.8523, c=9.854 | [47] | ||||||
RbBa2(CO3)2F | 499.19 | trigonal | R3 | a=10.2410 c=18.8277 Z=9 | 1710.1 | 4.362 | colourless | [44] | |||
Ba2Y(CO3)2F3 | 540.57 | Pbcn | a=9.458 b=6.966 c=11.787 | [2] | |||||||
Cs3Ba4(CO3)3F5 | 1223.12 | hexagonal | P63mc | a=11.516 c=7.613 Z=2 | 874.4 | 4.646 | [40] | ||||
Na3La2(CO3)4F | Lukechangite-(La) | 605.81 | Hexagonal | P63/mmc | a=5.083, c=23.034, Z=2 | [50] | |||||
Na2Eu(CO3)F3 | 314.94 | Orthorhombic | Pbca | a=6.596 b=10.774 c=14.09 Z=8 | 1001.3 | 4.178 | [51] | ||||
Na2Gd(CO3)F3 | 320.24 | orthorhombic | a=14.125 b=10.771 c=6.576 Z=8 | 1000.5 | 4.252 | <200 | 250 | colourless | [52] | ||
KGd(CO3)F2 | 294.35 | Orthorhombic | Fddd | a=7.006, b=11.181 and c=21.865 | [53] | ||||||
K4Gd2(CO3)3F4 | 726.91 | R32 | a=9.0268 c=13.684 | [2] | |||||||
BaSm(CO3)2F | 426.70 | R3m | a=5.016 c=37.944 | [2] | |||||||
Yb(CO3)(OH,F)·xH2O | [54] | ||||||||||
NaYb(CO3)F2 | 294.04 | a=6.897, b=9.118, c=6.219 | Horvathite structure | [54] | |||||||
Na2Yb(CO3)2F | 358.04 | monoclinic | C2/c | a=17.440, b=6.100, c=11.237, β=95.64° Z=8 | 1189.7 | [54] | |||||
Na3Yb(CO3)2F2 | 400.02 | monoclinic | Cc | a=7.127, b=29.916, c=6.928, β=112.56°; Z=8 | 1359 | [54] | |||||
Na4Yb(CO3)3F | 464.03 | monoclinic | Cc | a=8.018 b=15.929 c=13.950 β=101.425 Z=8 | 1746.4 | 3.53 | 263 | 300 | nonlinear deff=1.28pm/V | [55] | |
Na5Yb(CO3)4·2H2O | 564.05 | [54] | |||||||||
Na8Lu2(CO3)6F2 | 899.92 | monoclinic | Cc | a=8.007 b=15.910 c=13.916 β=101.318 Z=4 | 1738 | 3.439 | 250 | [56] | |||
Na3Lu(CO3)2F2 | 401.96 | monoclinic | Cc | a=7.073 b=29.77 c=6.909 β=111.92 Z=8 | 1349 | 3.957 | 220 | [56] | |||
Na2Lu(CO3)2F | 359.97 | monoclinic | C2/m | a=17.534 b=6.1084 c=11.284 β=111.924 Z=8 | 1203.2 | 3.974 | [56] | ||||
Tl3(CO3)F | thallous fluoride carbonate | 692.16 | Monoclinic | P21/m | a=7.510 b=7.407 c=6.069 γ=120° Z=2 | hexagonal prisms | [57] | ||||
Pb2(CO3)F2 | lead carbonate fluoride | 512.41 | Orthorhombic | Pbcn | a=8.0836 b=8.309 c=6.841 Z=4 | 444.6 | 7.41 | [2] [7] | |||
NaPb2(CO3)2F0.9(OH)0.1 | Hexagonal | P63/mmm | a=5.275 c=13.479 Z=2 | 325 | 5.893 | <269 | 260 | band gap 4.28 eV; high birefringence | [58] | ||
KPb2(CO3)2F | 592.5 | Hexagonal | P63/mmc | a=5.3000 c=13.9302 z=2 | 338.88 | 5.807 | 250 | colourless | [3] | ||
K2.70Pb5.15(CO3)5F3 | 1529.65 | Hexagonal | P-6m2 | a= 5.3123 c=18.620 z=1 | 455.07 | 5.582 | 250 | colourless non-linear peizoelectric | [3] | ||
K2Pb3(CO3)3F2 | 917.8 | Hexagonal | P63/mmc | a=5.2989 c=23.2326 z=2 | 564.94 | 5.395 | 287 | colourless | [41] | ||
RbPbCO3F | 371.67 | Hexagonal | P6̅m2 | a=5.3488 c=4.8269 Z=1 | 119.59 | 5.161 | colourless mon-linear | [59] | |||
CsPbCO3F | 419.11 | Hexagonal | P6̅m2 | a=5.393 c=5.116 z=1 | 128.8 | 5.401 | colourless non-linear | [59] | |||
BaPb2(CO3)2F2 | 709.74 | R3m | a=5.1865 c=23.4881 | [2] |
Dysprosium is a chemical element; it has symbol Dy and atomic number 66. It is a rare-earth element in the lanthanide series with a metallic silver luster. Dysprosium is never found in nature as a free element, though, like other lanthanides, it is found in various minerals, such as xenotime. Naturally occurring dysprosium is composed of seven isotopes, the most abundant of which is 164Dy.
Erbium is a chemical element; it has symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. It is a lanthanide, a rare-earth element, originally found in the gadolinite mine in Ytterby, Sweden, which is the source of the element's name.
Terbium is a chemical element; it has the symbol Tb and atomic number 65. It is a silvery-white, rare earth metal that is malleable and ductile. The ninth member of the lanthanide series, terbium is a fairly electropositive metal that reacts with water, evolving hydrogen gas. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime and euxenite.
The mineral bastnäsite (or bastnaesite) is one of a family of three carbonate-fluoride minerals, which includes bastnäsite-(Ce) with a formula of (Ce, La)CO3F, bastnäsite-(La) with a formula of (La, Ce)CO3F, and bastnäsite-(Y) with a formula of (Y, Ce)CO3F. Some of the bastnäsites contain OH− instead of F− and receive the name of hydroxylbastnasite. Most bastnäsite is bastnäsite-(Ce), and cerium is by far the most common of the rare earths in this class of minerals. Bastnäsite and the phosphate mineral monazite are the two largest sources of cerium and other rare-earth elements.
Calcium fluoride is the inorganic compound of the elements calcium and fluorine with the formula CaF2. It is a white solid that is practically insoluble in water. It occurs as the mineral fluorite (also called fluorspar), which is often deeply coloured owing to impurities.
Neodymium(III) chloride or neodymium trichloride is a chemical compound of neodymium and chlorine with the formula NdCl3. This anhydrous compound is a mauve-colored solid that rapidly absorbs water on exposure to air to form a purple-colored hexahydrate, NdCl3·6H2O. Neodymium(III) chloride is produced from minerals monazite and bastnäsite using a complex multistage extraction process. The chloride has several important applications as an intermediate chemical for production of neodymium metal and neodymium-based lasers and optical fibers. Other applications include a catalyst in organic synthesis and in decomposition of waste water contamination, corrosion protection of aluminium and its alloys, and fluorescent labeling of organic molecules (DNA).
Ytterbium(III) oxide is the chemical compound with the formula Yb2O3. It is one of the more commonly encountered compounds of ytterbium. It occurs naturally in trace amounts in the mineral gadolinite. It was first isolated from this in 1878 by Jean Charles Galissard de Marignac.
Cobalt(II) carbonate is the inorganic compound with the formula CoCO3. This pink paramagnetic solid is an intermediate in the hydrometallurgical purification of cobalt from its ores. It is an inorganic pigment, and a precursor to catalysts. Cobalt(II) carbonate also occurs as the rare red/pink mineral spherocobaltite.
Widgiemoolthalite is a rare hydrated nickel(II) carbonate mineral with the chemical formula (Ni,Mg)5(CO3)4(OH)2·5H2O. Usually bluish-green in color, it is a brittle mineral formed during the weathering of nickel sulfide. Present on gaspéite surfaces, widgiemoolthalite has a Mohs scale hardness of 3.5 and an unknown though likely disordered crystal structure. Widgiemoolthalite was first discovered in 1992 in Widgiemooltha, Western Australia, which is to date its only known source. It was named the following year by the three researchers who first reported its existence, Ernest H. Nickel, Bruce W. Robinson, and William G. Mumme.
Sheldrickite is a sodium calcium carbonate fluoride mineral, named in honor of George M. Sheldrick, former Professor of Crystallography at the University of Göttingen in Germany. Sheldrick is the creator of SHELLX computer program widely used for the analysis of crystal structures. Determination of the structure of this mineral required the software's capability of handling twinned crystals.
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 (BF4) or the fluorooxoborates which have fluorine bonded to boron.
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.
The carbonate chlorides are double salts containing both carbonate and chloride anions. Quite a few minerals are known. Several artificial compounds have been made. Some complexes have both carbonate and chloride ligands. They are part of the family of halocarbonates. In turn these halocarbonates are a part of mixed anion materials.
The borate carbonates are mixed anion compounds containing both borate and carbonate ions. Compared to mixed anion compounds containing halides, these are quite rare. They are hard to make, requiring higher temperatures, which are likely to decompose carbonate to carbon dioxide. The reason for the difficulty of formation is that when entering a crystal lattice, the anions have to be correctly located, and correctly oriented. They are also known as carbonatoborates or borocarbonates. Although these compounds have been termed carboborate, that word also refers to the C=B=C5− anion, or CB11H12− anion. This last anion should be called 1-carba-closo-dodecaborate or monocarba-closo-dodecaborate.
The sulfate carbonates are a compound carbonates, or mixed anion compounds that contain sulfate and carbonate ions. Sulfate carbonate minerals are in the 7.DG and 5.BF Nickel-Strunz groupings.
The iodate fluorides are chemical compounds which contain both iodate and fluoride anions (IO3− and F−). In these compounds fluorine is not bound to iodine as it is in fluoroiodates.
The sulfate fluorides are double salts that contain both sulfate and fluoride anions. They are in the class of mixed anion compounds. Some of these minerals are deposited in fumaroles.
A selenite fluoride is a chemical compound or salt that contains fluoride and selenite anions. These are mixed anion compounds. Some have third anions, including nitrate, molybdate, oxalate, selenate, silicate and tellurate.
Borate phosphates are mixed anion compounds containing separate borate and phosphate anions. They are distinct from the borophosphates where the borate is linked to a phosphate via a common oxygen atom. The borate phosphates have a higher ratio of cations to number of borates and phosphates, as compared to the borophosphates.
The borate bromides are mixed anion compounds that contain borate and bromide anions. They are in the borate halide family of compounds which also includes borate fluorides, borate chlorides, and borate iodides.