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The incommensurately modulated crystal structure of the mineral daliranite has been determined using 3D electron diffraction data obtained on nanocrystalline domains. Daliranite is orthorhombic with a = 21, b = 4.3, c = 9.5 Å and shows modulation satellites along c. The solution of the average structure in the Pnma space group together with energy-dispersive X-ray spectroscopy data obtained on the same domains indicate a chemical formula of PbHgAs2S5, which has one S fewer than previously reported. The crystal structure of daliranite is built from columns of face-sharing PbS8 bicapped trigonal prisms laterally connected by [2+4]Hg polyhedra and (As3+2S5)4− groups. The excellent quality of the electron diffraction data allows a structural model to be built for the modulated structure in superspace, which shows that the modulation is due to an alternated occupancy of a split As site.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S2052520619007340/dk5082sup1.cif
Contains datablocks global, average, modulated

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S2052520619007340/dk5082averagesup2.hkl
Contains datablock average

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S2052520619007340/dk5082modulatedsup3.hkl
Contains datablock modulated

pdf

Portable Document Format (PDF) file https://doi.org/10.1107/S2052520619007340/dk5082sup4.pdf
Figs S1 to S3 showing the diffuse scattering and details of the structural model that support the discussion in the text

B-IncStrDB reference: 15062EdDLkO

CCDC references: 1917352; 1917353

Computing details top

For both structures, data reduction: PETS 2.0 (Palatinus et al., 2011); program(s) used to solve structure: SIR2014 (Burla et al., 2015); program(s) used to refine structure: Jana2006 (Petricek et al., 2014); molecular graphics: Vesta (Momma & Izumi, 2011).

(average) top
Crystal data top
As2HgPbS5Dx = 5.493 Mg m3
Mr = 717.9Electron radiation, λ = 0.0335 Å
Orthorhombic, PnmaCell parameters from 2033 reflections
a = 21.246 (5) Åθ = 0.1–1.2°
b = 4.2897 (9) ŵ = 0 mm1
c = 9.5257 (12) ÅT = 298 K
V = 868.2 (3) Å3Needle, orange
Z = 40.0002 × 0.0001 × 0.0001 mm
F(000) = 1232
Data collection top
TEM
diffractometer
Rint = 0.335
Radiation source: LaB6θmax = 1.2°, θmin = 0.1°
10451 measured reflectionsh = 2020
562 independent reflectionsk = 43
401 reflections with I > 3σ(I)l = 810
Refinement top
Refinement on F0 restraints
R[F2 > 2σ(F2)] = 0.2440 constraints
wR(F2) = 0.303Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2)
S = 13.93(Δ/σ)max = 0.0002
562 reflectionsΔρmax = 0.45 e Å3
34 parametersΔρmin = 0.40 e Å3
Special details top

Experimental. data have been collected by precession assisted 3D electron diffraction

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Pb10.2886 (7)0.251.3368 (8)0.083 (6)
Hg10.4150 (6)0.250.9831 (7)0.065 (5)
As10.1286 (13)0.356 (3)1.1428 (18)0.030 (6)*0.5
As20.0526 (12)0.356 (3)0.8089 (16)0.019 (6)*0.5
S10.2233 (15)0.251.060 (2)0.034 (7)*
S20.1437 (15)0.250.690 (2)0.036 (7)*
S30.3337 (16)0.250.805 (2)0.042 (7)*
S40.4132 (13)0.251.4762 (19)0.019 (6)*
S50.4954 (15)0.251.160 (2)0.040 (7)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pb10.137 (16)0.101 (8)0.011 (5)00.0023320
Hg10.118 (14)0.069 (6)0.009 (5)00.0016520
Geometric parameters (Å, º) top
Pb1—S12.982 (17)
Pb1—S1—S2177.9
(modulated) top
Crystal data top
As2HgPbS5F(000) = 1232
Mr = 717.9Dx = 5.493 Mg m3
Orthorhombic, Pnma(00γ)0s0†Electron radiation, λ = 0.0335 Å
q = 0.262(2)c*Cell parameters from 10451 reflections
a = 21.246 (5) Åθ = 0.1–1.2°
b = 4.2897 (9) ŵ = 0 mm1
c = 9.5257 (12) ÅT = 298 K
V = 868.2 (3) Å3Needle, orange
Z = 40.0002 × 0.0001 × 0.0001 mm
† Symmetry operations: (1) x1, x2, x3, x4; (2) −x1+1/2, −x2, x3+1/2, x4+1/2; (3) −x1, x2+1/2, −x3, −x4+1/2; (4) x1+1/2, −x2+1/2, −x3+1/2, −x4; (5) −x1, −x2, −x3, −x4; (6) x1+1/2, x2, −x3+1/2, −x4+1/2; (7) x1, −x2+1/2, x3, x4+1/2; (8) −x1+1/2, x2+1/2, x3+1/2, x4.

Data collection top
TEM
diffractometer
Rint = 0.335
Radiation source: LaB6θmax = 1.2°, θmin = 0.1°
10451 measured reflectionsh = 2020
1503 independent reflectionsk = 43
981 reflections with I > 3σ(I)l = 810
Refinement top
Refinement on F0 restraints
R[F2 > 2σ(F2)] = 0.2720 constraints
wR(F2) = 0.310Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2)
S = 10.70(Δ/σ)max = 0.001
1503 reflectionsΔρmax = 0.45 e Å3
38 parametersΔρmin = 0.40 e Å3
Special details top

Experimental. data have been collected by precession assisted 3D electron diffraction

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Pb10.2885 (5)0.251.3367 (5)0.061 (4)
Hg10.4149 (5)0.250.9835 (5)0.063 (4)
As10.1285 (8)0.371 (2)1.1430 (11)0.031 (3)*0.5
As20.0517 (7)0.365 (2)0.8082 (10)0.027 (3)*0.5
S10.2236 (10)0.251.0596 (15)0.027 (4)*
S20.1430 (9)0.250.6898 (14)0.019 (4)*
S30.3344 (11)0.250.8066 (15)0.026 (4)*
S40.4134 (8)0.251.4756 (12)0.007 (4)*
S50.4962 (10)0.251.1610 (15)0.030 (5)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pb10.132 (11)0.033 (4)0.018 (3)00.003 (4)0
Hg10.122 (10)0.060 (4)0.006 (3)00.002 (3)0
Bond lengths (Å) top
AverageMinimumMaximum
Pb1—S12.982 (17)2.979 (17)2.986 (17)
Pb1—S1i3.031 (11)2.912 (11)3.151 (11)
Pb1—S1ii3.029 (11)2.912 (11)3.151 (11)
Pb1—S2i2.948 (13)2.808 (13)3.087 (13)
Pb1—S2ii2.945 (13)2.808 (13)3.087 (13)
Pb1—S3i3.403 (19)3.13 (2)3.69 (2)
Pb1—S3ii3.398 (19)3.13 (2)3.69 (2)
Pb1—S42.975 (19)2.963 (19)2.985 (19)
Hg1—S2i3.159 (12)3.114 (12)3.205 (12)
Hg1—S2ii3.159 (12)3.114 (12)3.205 (12)
Hg1—S32.40 (2)2.40 (2)2.40 (2)
Hg1—S52.43 (2)2.42 (2)2.45 (2)
Hg1—S5iii3.184 (16)2.880 (17)3.501 (17)
Hg1—S5iv3.179 (16)2.880 (17)3.501 (17)
As1—S12.20 (3)2.19 (3)2.26 (3)
As1—S3i3.287 (13)3.056 (14)3.397 (14)
As1—S3ii2.308 (16)2.224 (17)2.495 (17)
As1—S4v3.212 (13)3.141 (13)3.316 (13)
As1—S4vi2.460 (15)2.377 (15)2.518 (15)
As1—S5vii3.41 (2)3.39 (2)3.44 (2)
As2—S22.28 (2)2.26 (2)2.32 (2)
As2—S4v3.155 (12)3.080 (12)3.259 (12)
As2—S4vi2.426 (14)2.342 (14)2.489 (14)
As2—S5v3.239 (14)3.083 (14)3.309 (14)
As2—S5vi2.328 (17)2.272 (17)2.455 (17)
S1—S33.37 (3)3.37 (3)3.38 (3)
S1—S3i3.423 (18)3.164 (19)3.695 (19)
S1—S3ii3.419 (18)3.164 (19)3.695 (19)
S2—S5v3.67 (2)3.47 (3)3.88 (3)
S2—S5vi3.67 (2)3.47 (3)3.88 (3)
S4—S53.48 (2)3.48 (2)3.48 (2)
Symmetry codes: (i) x1+1/2, x2, x3+1/2, x4+1/2; (ii) x1+1/2, x2+1, x3+1/2, x4+1/2; (iii) x1+1, x21/2, x3+2, x4+1/2; (iv) x1+1, x2+1/2, x3+2, x4+1/2; (v) x1+1/2, x2, x31/2, x4+1/2; (vi) x1+1/2, x2+1, x31/2, x4+1/2; (vii) x11/2, x2+1/2, x3+5/2, x4.
 

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