The structure of tetragonal (
P2
1m) ammonium chlorite, NH
4ClO
2, has been redetermined by single-crystal X-ray analysis with higher precision. The NH
4+ cation is at a site of
symmetry, while the unique Cl and O atoms are at sites with symmetries
mm and
m, respectively. The structure consists of corrugated layers of NH
4+ cations coordinated by ClO
2- anions. The H atoms of the ammonium cation hydrogen bond to four chlorite O atoms. The resultant coordination is almost ideal tetrahedral.
Supporting information
Key indicators
- Single-crystal X-ray study
- T = 150 K
- Mean (Cl-O) = 0.001 Å
- R factor = 0.016
- wR factor = 0.040
- Data-to-parameter ratio = 11.9
checkCIF/PLATON results
No syntax errors found
Alert level C
PLAT431_ALERT_2_C Short Inter HL..A Contact Cl .. O .. 3.16 Ang.
PLAT431_ALERT_2_C Short Inter HL..A Contact Cl .. O .. 3.16 Ang.
PLAT431_ALERT_2_C Short Inter HL..A Contact Cl .. O .. 3.18 Ang.
PLAT431_ALERT_2_C Short Inter HL..A Contact Cl .. O .. 3.18 Ang.
Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
correct. If it is not, please give the correct count in the
_publ_section_exptl_refinement section of the submitted CIF.
From the CIF: _diffrn_reflns_theta_max 28.15
From the CIF: _reflns_number_total 203
Count of symmetry unique reflns 133
Completeness (_total/calc) 152.63%
TEST3: Check Friedels for noncentro structure
Estimate of Friedel pairs measured 70
Fraction of Friedel pairs measured 0.526
Are heavy atom types Z>Si present yes
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
4 ALERT level C = Check and explain
1 ALERT level G = General alerts; check
0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
4 ALERT type 2 Indicator that the structure model may be wrong or deficient
0 ALERT type 3 Indicator that the structure quality may be low
1 ALERT type 4 Improvement, methodology, query or suggestion
Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Bruker, 2004); program(s) used to refine structure: SHELXTL; molecular graphics: BS (Ozawa & Kang, 2004); software used to prepare material for publication: SHELXTL.
ammonium chlorate(III)
top
Crystal data top
NH4ClO2 | Dx = 1.881 Mg m−3 |
Mr = 85.49 | Mo Kα radiation, λ = 0.71073 Å |
Tetragonal, P421m | Cell parameters from 939 reflections |
Hall symbol: P -4 2ab | θ = 4.6–32.6° |
a = 6.3397 (3) Å | µ = 1.01 mm−1 |
c = 3.7560 (2) Å | T = 150 K |
V = 150.96 (1) Å3 | Needle, colourless |
Z = 2 | 0.42 × 0.12 × 0.07 mm |
F(000) = 88 | |
Data collection top
Bruker–Nonius X8 APEX CCD area-detector diffractometer | 203 independent reflections |
Radiation source: fine-focus sealed tube | 200 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.014 |
Detector resolution: 25 pixels mm-1 | θmax = 28.2°, θmin = 4.6° |
φ scans | h = −8→8 |
Absorption correction: multi-scan (SADABS; Bruker, 2004) | k = −8→8 |
Tmin = 0.676, Tmax = 0.932 | l = −4→2 |
1087 measured reflections | |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.016 | All H-atom parameters refined |
wR(F2) = 0.040 | w = 1/[σ2(Fo2) + (0.0174P)2 + 0.0433P] where P = (Fo2 + 2Fc2)/3 |
S = 1.26 | (Δ/σ)max < 0.001 |
203 reflections | Δρmax = 0.20 e Å−3 |
17 parameters | Δρmin = −0.25 e Å−3 |
0 restraints | Absolute structure: Flack (1983), 74 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: −0.02 (1) |
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 | |
Cl | 0.5000 | 0.0000 | 0.62877 (14) | 0.01303 (17) | |
N | 0.0000 | 0.0000 | 0.0000 | 0.0147 (4) | |
O | 0.35438 (14) | 0.14562 (14) | 0.3938 (4) | 0.0174 (3) | |
H | 0.111 (2) | 0.030 (3) | 0.125 (5) | 0.024 (4)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cl | 0.01297 (19) | 0.01297 (19) | 0.0132 (3) | 0.0001 (2) | 0.000 | 0.000 |
N | 0.0140 (5) | 0.0140 (5) | 0.0162 (9) | 0.000 | 0.000 | 0.000 |
O | 0.0152 (4) | 0.0152 (4) | 0.0220 (7) | 0.0020 (5) | −0.0036 (4) | 0.0036 (4) |
Geometric parameters (Å, º) top
Cl—Oi | 1.5759 (14) | N—Oii | 2.8438 (9) |
Cl—O | 1.5759 (14) | N—Oiii | 2.8438 (9) |
N—O | 2.8438 (9) | N—H | 0.866 (15) |
| | | |
O—Cl—Oi | 111.88 (12) | O—N—Oiii | 105.69 (2) |
O—N—Oii | 105.69 (3) | Oii—N—Oiii | 117.33 (5) |
Symmetry codes: (i) −x+1, −y, z; (ii) y, −x, −z; (iii) −y, x, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N—H···O | 0.866 (15) | 1.985 (15) | 2.8438 (9) | 171.2 (18) |