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The structure of tetragonal (P\overline 421m) ammonium chlorite, NH4ClO2, has been redetermined by single-crystal X-ray analysis with higher precision. The NH4+ cation is at a site of \overline 4 symmetry, while the unique Cl and O atoms are at sites with symmetries mm and m, respectively. The structure consists of corrugated layers of NH4+ cations coordinated by ClO2- anions. The H atoms of the ammonium cation hydrogen bond to four chlorite O atoms. The resultant coordination is almost ideal tetrahedral.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805005088/wm6052sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536805005088/wm6052Isup2.hkl
Contains datablock I

Key indicators

  • Single-crystal X-ray study
  • T = 150 K
  • Mean [sigma](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

Computing details top

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
NH4ClO2Dx = 1.881 Mg m3
Mr = 85.49Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P421mCell parameters from 939 reflections
Hall symbol: P -4 2abθ = 4.6–32.6°
a = 6.3397 (3) ŵ = 1.01 mm1
c = 3.7560 (2) ÅT = 150 K
V = 150.96 (1) Å3Needle, colourless
Z = 20.42 × 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 tube200 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.014
Detector resolution: 25 pixels mm-1θmax = 28.2°, θmin = 4.6°
φ scansh = 88
Absorption correction: multi-scan
(SADABS; Bruker, 2004)
k = 88
Tmin = 0.676, Tmax = 0.932l = 42
1087 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.016All 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 reflectionsΔρmax = 0.20 e Å3
17 parametersΔρmin = 0.25 e Å3
0 restraintsAbsolute structure: Flack (1983), 74 Friedel pairs
Primary atom site location: structure-invariant direct methodsAbsolute 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
xyzUiso*/Ueq
Cl0.50000.00000.62877 (14)0.01303 (17)
N0.00000.00000.00000.0147 (4)
O0.35438 (14)0.14562 (14)0.3938 (4)0.0174 (3)
H0.111 (2)0.030 (3)0.125 (5)0.024 (4)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl0.01297 (19)0.01297 (19)0.0132 (3)0.0001 (2)0.0000.000
N0.0140 (5)0.0140 (5)0.0162 (9)0.0000.0000.000
O0.0152 (4)0.0152 (4)0.0220 (7)0.0020 (5)0.0036 (4)0.0036 (4)
Geometric parameters (Å, º) top
Cl—Oi1.5759 (14)N—Oii2.8438 (9)
Cl—O1.5759 (14)N—Oiii2.8438 (9)
N—O2.8438 (9)N—H0.866 (15)
O—Cl—Oi111.88 (12)O—N—Oiii105.69 (2)
O—N—Oii105.69 (3)Oii—N—Oiii117.33 (5)
Symmetry codes: (i) x+1, y, z; (ii) y, x, z; (iii) y, x, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N—H···O0.866 (15)1.985 (15)2.8438 (9)171.2 (18)
 

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