Buy article online - an online subscription or single-article purchase is required to access this article.
The title compound, (NH4)2HgCl2(NO3)2, is a double salt of HgCl2 and NH4NO3 and can also be written as `HgCl2·2NH4NO3'. The structure contains HgCl2 units which are connected by nitrate groups, through long links of ca. 2.90 Å, to give chains running along [010]. All atoms apart from the two oxygen atoms are located on a mirror plane perpendicular to the b axis. The coordination around mercury is a distorted hexagonal bipyramid.
Supporting information
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (Hg-Cl) = 0.001 Å
- H-atom completeness 1%
- R factor = 0.019
- wR factor = 0.047
- Data-to-parameter ratio = 15.7
checkCIF results
No syntax errors found
ADDSYM reports no extra symmetry
General Notes
FORMU_01 There is a discrepancy between the atom counts in the
_chemical_formula_sum and the formula from the _atom_site* data.
Atom count from _chemical_formula_sum:H8 Cl2 Hg1 N4 O6
Atom count from the _atom_site data: Cl2 Hg1 N4 O6
CELLZ_01
From the CIF: _cell_formula_units_Z 4
From the CIF: _chemical_formula_sum Cl2 H8 Hg N4 O6
TEST: Compare cell contents of formula and atom_site data
atom Z*formula cif sites diff
Cl 8.00 8.00 0.00
H 32.00 0.00 32.00
Hg 4.00 4.00 0.00
N 16.00 16.00 0.00
O 24.00 24.00 0.00
Difference between formula and atom_site contents detected.
WARNING: H atoms missing from atom site list. Is this intentional?
CHEMW_03
From the CIF: _cell_formula_units_Z 4
From the CIF: _chemical_formula_weight 431.59
TEST: Calculate formula weight from _atom_site_*
atom mass num sum
Hg 200.59 1.00 200.59
Cl 35.45 2.00 70.91
O 16.00 6.00 95.99
N 14.01 4.00 56.03
Calculated formula weight 423.52
The ratio of given/expected molecular weight as calculated
from the _atom_site* data lies outside
the range 0.99 <> 1.01
Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-STEP32 (Stoe & Cie, 2000); data reduction: X-RED (Stoe & Cie, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXL97.
Crystal data top
(NH4)2HgCl2(NO3)2 | F(000) = 760 |
Mr = 431.59 | Dx = 2.967 Mg m−3 |
Orthorhombic, Pnma | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2n | Cell parameters from 23769 reflections |
a = 15.5758 (16) Å | θ = 2.2–27.0° |
b = 5.4976 (5) Å | µ = 16.49 mm−1 |
c = 11.2826 (15) Å | T = 293 K |
V = 966.12 (18) Å3 | Prism, colorless |
Z = 4 | 0.3 × 0.2 × 0.1 mm |
Data collection top
Stoe Imaging Plate Diffraction System diffractometer | 1163 independent reflections |
Radiation source: fine-focus sealed tube | 983 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.061 |
φ scans | θmax = 27.0°, θmin = 2.2° |
Absorption correction: numerical (X-SHAPE; Stoe & Cie, 1998) | h = −19→19 |
Tmin = 0.027, Tmax = 0.192 | k = −7→6 |
14614 measured reflections | l = −14→14 |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.019 | H-atom parameters not refined |
wR(F2) = 0.047 | w = 1/[σ2(Fo2) + (0.0315P)2] where P = (Fo2 + 2Fc2)/3 |
S = 0.94 | (Δ/σ)max = 0.001 |
1163 reflections | Δρmax = 0.57 e Å−3 |
74 parameters | Δρmin = −0.67 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0053 (2) |
Special details top
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor
wR and goodness of fit S are based on F2, conventional
R-factors R are based on F, with F set to zero for
negative F2. The threshold expression of F2 >
σ(F2) is used only for calculating R-factors(gt) etc.
and is not relevant to the choice of reflections for refinement.
R-factors based on F2 are statistically about twice as large
as those based on F, and R- factors based on ALL data will be
even larger. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Hg1 | 0.169811 (12) | 0.7500 | 0.255661 (15) | 0.02896 (11) | |
Cl1 | 0.14553 (11) | 0.7500 | 0.05452 (11) | 0.0401 (3) | |
Cl2 | 0.19354 (11) | 0.7500 | 0.45760 (11) | 0.0405 (3) | |
O1 | 0.2002 (3) | 0.2500 | 0.2594 (4) | 0.0466 (12) | |
O2 | 0.31904 (18) | 0.0530 (7) | 0.2396 (2) | 0.0389 (7) | |
O3 | 0.01854 (19) | 0.0545 (6) | 0.3154 (3) | 0.0530 (9) | |
O4 | −0.0002 (3) | 0.2500 | 0.1533 (3) | 0.0461 (11) | |
N1 | 0.2799 (3) | 0.2500 | 0.2462 (3) | 0.0270 (9) | |
N2 | 0.0120 (3) | 0.2500 | 0.2608 (3) | 0.0273 (9) | |
N3 | 0.1048 (3) | 0.2500 | 0.5474 (4) | 0.0382 (11) | |
N4 | 0.4205 (3) | 0.7500 | 0.4098 (5) | 0.0378 (12) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Hg1 | 0.03194 (14) | 0.02901 (14) | 0.02593 (13) | 0.000 | −0.00203 (8) | 0.000 |
Cl1 | 0.0519 (8) | 0.0418 (8) | 0.0265 (6) | 0.000 | −0.0067 (5) | 0.000 |
Cl2 | 0.0562 (8) | 0.0398 (8) | 0.0256 (6) | 0.000 | −0.0028 (6) | 0.000 |
O1 | 0.0236 (19) | 0.032 (2) | 0.085 (4) | 0.000 | 0.0073 (19) | 0.000 |
O2 | 0.0401 (15) | 0.0351 (18) | 0.0415 (16) | 0.0123 (13) | 0.0012 (11) | −0.0010 (12) |
O3 | 0.0397 (17) | 0.051 (2) | 0.068 (2) | −0.0005 (15) | 0.0005 (15) | 0.0285 (17) |
O4 | 0.045 (2) | 0.066 (3) | 0.0270 (19) | 0.000 | −0.0020 (17) | 0.000 |
N1 | 0.029 (2) | 0.027 (2) | 0.025 (2) | 0.000 | 0.0025 (15) | 0.000 |
N2 | 0.0222 (19) | 0.030 (2) | 0.030 (2) | 0.000 | −0.0012 (15) | 0.000 |
N3 | 0.052 (3) | 0.033 (3) | 0.029 (2) | 0.000 | −0.004 (2) | 0.000 |
N4 | 0.044 (3) | 0.032 (3) | 0.038 (3) | 0.000 | −0.0078 (19) | 0.000 |
Geometric parameters (Å, º) top
Hg1—Cl1 | 2.3007 (13) | O3—N2 | 1.243 (3) |
Hg1—Cl2 | 2.3082 (13) | O4—N2 | 1.227 (5) |
O1—N1 | 1.249 (6) | N1—O2i | 1.245 (4) |
O2—N1 | 1.245 (4) | N2—O3i | 1.243 (3) |
| | | |
Cl1—Hg1—Cl2 | 179.75 (5) | O4—N2—O3i | 120.1 (2) |
O2i—N1—O2 | 120.8 (5) | O4—N2—O3 | 120.1 (2) |
O2i—N1—O1 | 119.6 (2) | O3i—N2—O3 | 119.7 (5) |
O2—N1—O1 | 119.6 (2) | | |
Symmetry code: (i) x, −y+1/2, z. |
Subscribe to Acta Crystallographica Section E: Crystallographic Communications
The full text of this article is available to subscribers to the journal.
If you have already registered and are using a computer listed in your registration details, please email
support@iucr.org for assistance.