research papers
Two samples of pure NiCl(OH) were produced by hydrothermal synthesis and characterized by chemical analysis, IR spectroscopy, high-resolution laboratory X-ray powder diffraction and scanning electron microscopy. Layers composed of edge-sharing distorted NiCl6x(OH)6−6x octahedra were identified as the main building blocks of the crystal structure. NiCl(OH) is isostructural to CoOOH and crystallizes in space group Rm [a = 3.2606 (1), c = 17.0062 (9) Å]. Each sample exhibits faults in the stacking pattern of the layers. Crystal intergrowth of (AγB)(BαC)(CβA) and (AγB)(AγB) [C6 like, β-Ni(OH)2 related] stacked layers was identified as the main feature of the microstructure of NiCl(OH) by DIFFaX simulations. A recursion routine for creating distinct stacking patterns of rigid-body-like layers in real space with distinct faults (global optimization) and a Rietveld-compatible approach (local optimization) was realized and implemented in a macro for the program TOPAS for the first time. This routine enables a recursive creation of supercells containing (AγB)(BαC)(CβA), (AγB)(AγB) and (CβA)(BαC)(AγB) stacking patterns, according to user-defined transition probabilities. Hence it is an enhancement of the few previously published Rietveld-compatible approaches. This routine was applied successfully to create and adapt a detailed microstructure model to the measured data of two stacking-faulted NiCl(OH) samples. The obtained microstructure models were supported by high-resolution scanning electron microscopy images.
Keywords: alkaline nickel(II) chlorides; X-ray powder diffraction; stacking faults; microstructure of layered compounds.
Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600576715017719/po5043sup1.cif | |
Rietveld powder data file (CIF format) https://doi.org/10.1107/S1600576715017719/po5043Isup2.rtv | |
Portable Document Format (PDF) file https://doi.org/10.1107/S1600576715017719/po5043sup3.pdf |
CCDC reference: 1426206
Computing details top
(I) top
Crystal data top
ClHNiO | V = 156.58 Å3 |
Mr = 111.15 | Z = 3 |
Trigonal, R3m | Dx = 3.66 Mg m−3 |
a = 3.26061 (8) Å | Mo Kα radiation, λ = 0.70930 Å |
c = 17.0062 (9) Å | T = 295 K |
Data collection top
'Bruker D8-Advance, Debye-Scherrer mode, MPI-FKF, Stuttgart, Germany' diffractometer | Data collection mode: transmission |
Johannson Ge(220) primary beam monochromator | Scan method: step |
Specimen mounting: '0.5 mm glass capillary' | 2θmin = 2.0°, 2θmax = 60.0°, 2θstep = 0.005° |
Refinement top
Rp = 0.050 | χ2 = 3.568 |
Rwp = 0.067 | Profile function: Fundamental parameters |
Rexp = 0.036 | 42 parameters |
R(F2) = 0.0200 | Background function: 'Chebyshev polynomial' |
Crystal data top
ClHNiO | V = 156.58 Å3 |
Mr = 111.15 | Z = 3 |
Trigonal, R3m | Mo Kα radiation, λ = 0.70930 Å |
a = 3.26061 (8) Å | T = 295 K |
c = 17.0062 (9) Å |
Data collection top
'Bruker D8-Advance, Debye-Scherrer mode, MPI-FKF, Stuttgart, Germany' diffractometer | Scan method: step |
Specimen mounting: '0.5 mm glass capillary' | 2θmin = 2.0°, 2θmax = 60.0°, 2θstep = 0.005° |
Data collection mode: transmission |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
x | y | z | Biso*/Beq | Occ. (<1) | |
Ni1 | 0 | 0 | 0 | 1.21 (2) | |
O1 | 0.33333 | 0.66667 | 0.0350 (2) | 0.44 (3) | 0.5 |
Cl1 | 0.33333 | 0.66667 | 0.08790 (8) | 0.44 (3) | 0.5 |
Geometric parameters (Å, º) top
Ni1—O1 | 1.9744 (11) | Ni1—Cl1 | 2.4038 (9) |
O1i—Ni1i—Cl1i | 20.9 (1) |
Symmetry code: (i) −x, −x+y, −z. |
Experimental details
Crystal data | |
Chemical formula | ClHNiO |
Mr | 111.15 |
Crystal system, space group | Trigonal, R3m |
Temperature (K) | 295 |
a, c (Å) | 3.26061 (8), 17.0062 (9) |
V (Å3) | 156.58 |
Z | 3 |
Radiation type | Mo Kα, λ = 0.70930 Å |
µ (mm−1) | ? |
Specimen shape, size (mm) | Cylinder, ? × ? × ? |
Data collection | |
Data collection method | 'Bruker D8-Advance, Debye-Scherrer mode, MPI-FKF, Stuttgart, Germany' |
Specimen mounting | '0.5 mm glass capillary' |
Data collection mode | Transmission |
Scan method | Step |
2θ values (°) | 2θmin = 2.0 2θmax = 60.0 2θstep = 0.005 |
Refinement | |
R factors and goodness of fit | Rp = 0.050, Rwp = 0.067, Rexp = 0.036, R(F2) = 0.0200, χ2 = 3.568 |
No. of parameters | 42 |
No. of restraints | ? |