Chemistry:Potassium trichloridocuprate(II)
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| KCuCl3 | |
| Molar mass | 208.99 g·mol−1 |
| Appearance | garnet-red crystals[1] |
| Density | 2.86 g/cm3[1] |
| Solubility | methanol,[2] ethanol[2] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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Potassium trichloridocuprate(II) is a salt with chemical formula KCuCl
3, more properly [K+]
2[Cu
2Cl2−
6].[3][4]
It is a member of the "halide" sub-family of perovskite materials with general formula ABX
3 where A is a monovalent cation, B is a divalent cation, and X is a halide anion.[5]
The compound occurs in nature as the bright red mineral sanguite.[1]
The compound is also called potassium trichlorocuprate(II), potassium copper(II) trichloride, potassium cupric chloride and other similar names. The latter is used also for potassium tetrachloridocuprate(II) K
2CuCl
4.[1]
Preparation and properties
The compound can be obtained by evaporation of a solution of potassium chloride KCl and copper(II) chloride CuCl
2 in 1:1 mole ratio.[3]
The anhydrous form is garnet-red.[6] It can be crystallized from a molten mixture of potassium chloride KCl and copper(II) chloride CuCl
2.[7][2] or by evaporation from a solution of the salts in ethanol.[5] It is very hygroscopic,[5] and soluble in methanol and ethanol.[2] It is antiferromagnetic below 30 K, and pleochroic, with maximum visible absorption when the electric vector is parallel to the Cu–Cu vector of the dimer.[6][8]
Structure
Anhydrous
The anhydrous mineral form (sanguite) has the monoclinic crystal structure, with symmetry group P21/c and lattice parameters a = 402.81 pm, b = 1379.06 pm, c = 873.35 pm, and β = 97.137°, cell volume V = 0.48138 nm3, and formulas per cell Z = 4.[1][9] The measured density is 2.86 g/cm3, close to the calculated one 2.88 g/cm3. It contains discrete almost planar anions [Cu
2Cl
6]2−, each with the two copper atoms connected by two bridging chlorine atoms. These anions are arranged in columns consisting of distorted edge-sharing CuCl
6 octahedra, stacked in double chains parallel to the a axis. The columns
occupy the edges and the centre of the cell's projection on the bc plane.[1][9][6] The potassium atoms are located between these columns; each K+ cation is surrounded by nine chlorine atoms.[1] The mineral is optically biaxial (negative), with α = 1.653, β = 1.780, γ = 1.900', 2V= 85°. The mineral is named from the Latin sanguis (blood), alluding to its color.[1]
Theoretical calculations for this topology give the lattice parameters as a = 1388.1 pm, b = 427.7 pm, c = 896.5 pm, α = 79.855°, cell volume V = 0.523891 nm3, calculated density 2.65 g/cm3.[10]
Theoretical
An alternative theoretical structure for the compound has a cubic crystal system, symmetry group Pm3m[221], with the copper atoms arranged as corners of a cubic grid, a potassium atom at the center of each cube and a chlorine atom at the midpoint of each edge. The latice parameters are a = b = c = 485.8 pm, V = 0.114684 nm3, predicted density 3.03 g/cm3.[11]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Pekov, Igor V.; Zubkova, Natalia V.; Belakovskiy, Dmitry I.; Lykova, Inna S.; Yapaskurt, Vasiliy O.; Vigasina, Marina F.; Sidorov, Evgeny G.; Pushcharovsky, Dmitry Yu. (2015). "Sanguite, KCuCl3, A New Mineral from the Tolbachik Volcano, Kamchatka, Russia". The Canadian Mineralogist 53 (4): 633–641. doi:10.3749/canmin.1500012.
- ↑ 2.0 2.1 2.2 2.3 Kuroe, H.; Takami, N.; Niwa, N.; Sekine, T.; Matsumoto, M.; Yamada, F.; Tanaka, H.; Takemura, K. (2012). "Longitudinal magnetic excitation in KCuCl3 studied by Raman scattering under hydrostatic pressures". Journal of Physics: Conference Series 400 (3): 032042. doi:10.1088/1742-6596/400/3/032042. Bibcode: 2012JPhCS.400c2042K.
- ↑ 3.0 3.1 Smith, D.W. (1976). "Chlorocuprates(II)". Coordination Chemistry Reviews 21 (2–3): 93–158. doi:10.1016/S0010-8545(00)80445-2.
- ↑ "Potassium trichlorocuprate(1-)". Chemical page 44145367 at the PubChem website. Accessed on 2022-07-18.
- ↑ 5.0 5.1 5.2 McMurdie, H.F.; De Groot, J.; Morris, M.; Swanson, H.E. (1969). "Crystallography and preparation of some ABCl3 compounds". Journal of Research of the National Bureau of Standards Section A 73A (6): 621. doi:10.6028/jres.073A.049.
- ↑ 6.0 6.1 6.2 Willett, Roger D.; Dwiggins, Claudius; Kruh, R. F.; Rundle, R. E. (1963). "Crystal Structures of KCuCl3 and NH4CuCl3". The Journal of Chemical Physics 38 (10): 2429–2436. doi:10.1063/1.1733520. Bibcode: 1963JChPh..38.2429W.
- ↑ Kato, T.; Oosawa, A.; Takatsu, K.; Tanaka, H.; Shiramura, W.; Nakajima, K.; Kakurai, K. (1999). "Magnetic excitations in the spin gap system KCuCl3 and TlCuCl3". Journal of Physics and Chemistry of Solids 60 (8–9): 1125–1128. doi:10.1016/S0022-3697(99)00072-4. Bibcode: 1999JPCS...60.1125K.
- ↑ Cavadini, N.; Henggeler, W.; Furrer, A.; Güdel, H.-U.; Krämer, K.; Mutka, H. (1999). "Magnetic excitations in the quantum spin system KCuCl". The European Physical Journal B 7 (4): 519–522. doi:10.1007/s100510050642. Bibcode: 1999EPJB....7..519C.
- ↑ 9.0 9.1 Cavadini, N.; Heigold, G.; Henggeler, W.; Furrer, A.; Güdel, H-U; Krämer, K.; Mutka, H. (2000). "Quantum magnetic interactions in S = 1/2 KCuCl3". Journal of Physics: Condensed Matter 12 (25): 5463–5472. doi:10.1088/0953-8984/12/25/310. Bibcode: 2000JPCM...12.5463C.
- ↑ None Available (2020). Materials Data on KCuCl3 by Materials Project. LBNL Materials Project; Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). doi:10.17188/1201674.
- ↑ None Available (2017). Materials Data on KCuCl3 (SG:221) by Materials Project. LBNL Materials Project; Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). doi:10.17188/1354951.
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