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The crystal structure of cesbronite has been determined using single-crystal X-ray diffraction and supported by electron-microprobe analysis, powder diffraction and Raman spectroscopy. Cesbronite is orthorhombic, space group Cmcm, with a = 2.93172 (16), b = 11.8414 (6), c = 8.6047 (4) Å and V = 298.72 (3) Å3. The chemical formula of cesbronite has been revised to CuII3TeVIO4(OH)4 from CuII5(TeIVO3)2(OH)6·2H2O. This change has been accepted by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, Proposal 17-C. The previously reported oxidation state of tellurium has been shown to be incorrect; the crystal structure, bond valence studies and charge balance clearly show tellurium to be hexavalent. The crystal structure of cesbronite is formed from corrugated sheets of edge-sharing CuO6 and (Cu0.5Te0.5)O6 octahedra. The structure determined here is an average structure that has underlying ordering of Cu and Te at one of the two metal sites, designated as M, which has an occupancy Cu0.5Te0.5. This averaging probably arises from an absence of correlation between adjacent polyhedral sheets, as there are two different hydrogen-bonding configurations linking sheets that are related by a ½a offset. Randomised stacking of these two configurations results in the superposition of Cu and Te and leads to the Cu0.5Te0.5 occupancy of the M site in the average structure. Bond-valence analysis is used to choose the most probable Cu/Te ordering scheme and also to identify protonation sites (OH). The chosen ordering scheme and its associated OH sites are shown to be consistent with the revised chemical formula.

Supporting information


Portable Document Format (PDF) file
Powder diffraction data in table format


Crystallographic Information File (CIF)
Contains datablock I


Structure factor file (CIF format)
Contains datablock I

CCDC reference: 1585827

Computing details top

Data collection: CrysAlis PRO, Agilent Technologies, Version (release 27-10-2011 CrysAlis171 .NET); cell refinement: CrysAlis PRO, Agilent Technologies, Version (release 27-10-2011 CrysAlis171 .NET); data reduction: CrysAlis PRO, Agilent Technologies, Version (release 27-10-2011 CrysAlis171 .NET); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2016/6 (Sheldrick, 2016).

(I) top
Crystal data top
Cu3O8TeH4Dx = 4.961 Mg m3
Mr = 446.22Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, CmcmCell parameters from 857 reflections
a = 2.93172 (16) Åθ = 5.9–31.1°
b = 11.8414 (6) ŵ = 15.37 mm1
c = 8.6047 (4) ÅT = 293 K
V = 298.72 (3) Å3Triangular plate, translucent emerald green
Z = 20.05 × 0.03 × 0.02 mm
F(000) = 406
Data collection top
Xcalibur, Eos
763 independent reflections
Radiation source: Enhance (Mo) X-ray Source649 reflections with I > 2σ(I)
Detector resolution: 16.0869 pixels mm-1Rint = 0.037
1K CCD area detector scansθmax = 32.7°, θmin = 3.4°
Absorption correction: multi-scan
Multi-scan ABSPACK
h = 44
Tmin = 0.801, Tmax = 1.000k = 1717
764 measured reflectionsl = 1212
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullH-atom parameters not defined
R[F2 > 2σ(F2)] = 0.032 w = 1/[σ2(Fo2) + (0.0378P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.068(Δ/σ)max < 0.001
S = 1.04Δρmax = 1.45 e Å3
326 reflectionsΔρmin = 2.09 e Å3
25 parameters
Special details top

Experimental. CrysAlisPro, Agilent Technologies, Version (release 01-02-2013 CrysAlis171 .NET) (compiled Feb 1 2013,16:14:44) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refined as a 2-component twin.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Cu10.0000000.35007 (10)0.7500000.0076 (3)
Te20.5000000.5000000.5000000.0061 (2)0.509 (9)
Cu20.5000000.5000000.5000000.0061 (2)0.491 (9)
O10.5000000.4614 (7)0.7500000.038 (2)
O20.5000000.2384 (5)0.7500000.0086 (12)
O31.0000000.3928 (4)0.4789 (4)0.0087 (9)
Atomic displacement parameters (Å2) top
Cu10.0051 (5)0.0085 (6)0.0092 (5)0.0000.0000.000
Te20.0039 (3)0.0078 (4)0.0066 (3)0.0000.0000.0005 (3)
Cu20.0039 (3)0.0078 (4)0.0066 (3)0.0000.0000.0005 (3)
O10.008 (3)0.008 (3)0.097 (8)0.0000.0000.000
O20.005 (3)0.009 (3)0.011 (3)0.0000.0000.000
O30.0097 (19)0.008 (2)0.008 (2)0.0000.0000.0002 (16)
Geometric parameters (Å, º) top
Cu1—O1i1.971 (5)Te2—O3iv1.948 (3)
Cu1—O11.971 (5)Te2—O3v1.948 (3)
Cu1—O2i1.974 (4)Te2—O3i1.948 (3)
Cu1—O21.974 (4)Te2—O31.948 (3)
Cu1—O3ii2.387 (4)Te2—O12.1992 (17)
Cu1—O3i2.387 (4)Te2—O1iv2.1992 (17)
Cu1—Cu1i2.9317 (2)Te2—Te2iii2.9317 (1)
Cu1—Cu1iii2.9317 (2)Te2—Te2i2.9317 (2)
O1i—Cu1—O196.1 (3)O3i—Te2—O397.64 (19)
O1i—Cu1—O2i84.0 (2)O3iv—Te2—O192.53 (17)
O1—Cu1—O2i179.9 (2)O3v—Te2—O192.53 (17)
O1i—Cu1—O2179.9 (2)O3i—Te2—O187.47 (17)
O1—Cu1—O284.0 (2)O3—Te2—O187.47 (17)
O2i—Cu1—O295.9 (3)O3iv—Te2—O1iv87.47 (17)
O1i—Cu1—O3ii81.85 (7)O3v—Te2—O1iv87.47 (17)
O1—Cu1—O3ii81.85 (7)O3i—Te2—O1iv92.53 (17)
O2i—Cu1—O3ii98.16 (7)O3—Te2—O1iv92.53 (17)
O2—Cu1—O3ii98.16 (7)O1—Te2—O1iv180.0
O1i—Cu1—O3i81.85 (7)O3iv—Te2—Te2iii138.82 (10)
O1—Cu1—O3i81.85 (7)O3v—Te2—Te2iii41.18 (10)
O2i—Cu1—O3i98.16 (7)O3i—Te2—Te2iii138.82 (10)
O2—Cu1—O3i98.16 (7)O3—Te2—Te2iii41.18 (10)
O3ii—Cu1—O3i155.5 (2)O1—Te2—Te2iii90.000 (1)
O1i—Cu1—Cu1i41.97 (17)O1iv—Te2—Te2iii90.000 (1)
O1—Cu1—Cu1i138.03 (17)O3iv—Te2—Te2i41.18 (10)
O2i—Cu1—Cu1i42.05 (13)O3v—Te2—Te2i138.82 (10)
O2—Cu1—Cu1i137.95 (13)O3i—Te2—Te2i41.18 (10)
O3ii—Cu1—Cu1i90.0O3—Te2—Te2i138.82 (10)
O3i—Cu1—Cu1i90.0O1—Te2—Te2i90.000 (1)
O1i—Cu1—Cu1iii138.03 (17)O1iv—Te2—Te2i90.000 (1)
O1—Cu1—Cu1iii41.97 (17)Te2iii—Te2—Te2i180.0
O2i—Cu1—Cu1iii137.95 (13)Cu1iii—O1—Cu196.1 (3)
O2—Cu1—Cu1iii42.05 (13)Cu1iii—O1—Te2vi97.99 (11)
O3ii—Cu1—Cu1iii90.0Cu1—O1—Te2vi97.99 (11)
O3i—Cu1—Cu1iii90.000 (1)Cu1iii—O1—Te297.99 (11)
Cu1i—Cu1—Cu1iii180.0Cu1—O1—Te297.99 (11)
O3iv—Te2—O3v97.64 (19)Te2vi—O1—Te2156.0 (4)
O3iv—Te2—O3i82.36 (19)Cu1—O2—Cu1iii95.9 (3)
O3v—Te2—O3i180.0Te2—O3—Te2iii97.63 (19)
O3iv—Te2—O3180.0Te2—O3—Cu1iii92.69 (13)
O3v—Te2—O382.36 (19)Te2iii—O3—Cu1iii92.69 (13)
Symmetry codes: (i) x+1, y, z; (ii) x+1, y, z+3/2; (iii) x1, y, z; (iv) x1, y+1, z+1; (v) x2, y+1, z+1; (vi) x1, y+1, z+1/2.

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