The title compound, sodium tetramagnesium tris(arsenate), was prepared by solid-state reaction at 1243 K. The structure is built up from edge-sharing MgO
6 octahedra associated with the AsO
4 arsenate groups. The three-dimensional network encloses cavities in which Na
+ cations are located. This compound exhibits the NaMg
4(VO
4)
3 structure. The Na and one of the As atoms are on positions of
symmetry and the remaining cations all lie on twofold axes.
Supporting information
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (Mg-O) = 0.003 Å
- R factor = 0.018
- wR factor = 0.045
- Data-to-parameter ratio = 10.9
checkCIF/PLATON results
No syntax errors found
Alert level A
PLAT052_ALERT_1_A (Proper) Absorption Correction Method Missing .. ?
PLAT057_ALERT_3_A Correction for Absorption Required RT(exp) ... 1.60
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 27.93
From the CIF: _reflns_number_total 525
Count of symmetry unique reflns 322
Completeness (_total/calc) 163.04%
TEST3: Check Friedels for noncentro structure
Estimate of Friedel pairs measured 203
Fraction of Friedel pairs measured 0.630
Are heavy atom types Z>Si present yes
2 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
0 ALERT level C = Check and explain
1 ALERT level G = General alerts; check
1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
0 ALERT type 2 Indicator that the structure model may be wrong or deficient
1 ALERT type 3 Indicator that the structure quality may be low
1 ALERT type 4 Improvement, methodology, query or suggestion
Data collection: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); cell refinement: CAD-4 EXPRESS; data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97.
Sodium tetramagnesium tris(arsenate)
top
Crystal data top
NaMg4(AsO4)3 | Dx = 3.989 Mg m−3 |
Mr = 536.96 | Mo Kα radiation, λ = 0.71073 Å |
Tetragonal, I42d | Cell parameters from 25 reflections |
Hall symbol: I -4 2bw | θ = 2–27° |
a = 6.817 (1) Å | µ = 11.55 mm−1 |
c = 19.242 (3) Å | T = 293 K |
V = 894.2 (2) Å3 | Prismatic, colourless |
Z = 4 | 0.1 × 0.07 × 0.04 mm |
F(000) = 1016 | |
Data collection top
Enraf-Nonius CAD-4 diffractometer | 500 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.031 |
Graphite monochromator | θmax = 27.9°, θmin = 3.2° |
ω/2θ scans | h = −8→4 |
Absorption correction: ψ scan (North et al., 1968) | k = −1→8 |
Tmin = 0.394, Tmax = 0.630 | l = −1→25 |
1111 measured reflections | 2 standard reflections every 120 min |
525 independent reflections | intensity decay: 0.4% |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.0194P)2] where P = (Fo2 + 2Fc2)/3 |
R[F2 > 2σ(F2)] = 0.018 | (Δ/σ)max < 0.001 |
wR(F2) = 0.045 | Δρmax = 0.39 e Å−3 |
S = 1.10 | Δρmin = −0.49 e Å−3 |
525 reflections | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
48 parameters | Extinction coefficient: 0.0016 (3) |
0 restraints | Absolute structure: Flack (1983), with xx Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: −0.003 (17) |
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 | |
As1 | 0.0000 | 0.0000 | 0.0000 | 0.00350 (18) | |
As2 | 0.34467 (8) | −0.7500 | 0.1250 | 0.00424 (15) | |
Mg1 | 0.0000 | −0.5000 | 0.02054 (9) | 0.0061 (4) | |
Mg2 | 0.7588 (3) | −0.7500 | 0.1250 | 0.0064 (4) | |
Na | 0.5000 | −0.5000 | 0.0000 | 0.0128 (7) | |
O1 | 0.5064 (4) | −0.7959 (4) | 0.05961 (13) | 0.0077 (6) | |
O2 | 0.2227 (4) | −0.5460 (4) | 0.09958 (12) | 0.0070 (5) | |
O3 | −0.0581 (4) | 0.2068 (4) | 0.04410 (13) | 0.0073 (6) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
As1 | 0.0037 (2) | 0.0037 (2) | 0.0032 (3) | 0.000 | 0.000 | 0.000 |
As2 | 0.0048 (3) | 0.0038 (3) | 0.0041 (2) | 0.000 | 0.000 | 0.0000 (2) |
Mg1 | 0.0090 (9) | 0.0052 (9) | 0.0041 (7) | 0.0000 (8) | 0.000 | 0.000 |
Mg2 | 0.0059 (8) | 0.0076 (8) | 0.0056 (9) | 0.000 | 0.000 | 0.0014 (7) |
Na | 0.0121 (10) | 0.0121 (10) | 0.0141 (15) | 0.000 | 0.000 | 0.000 |
O1 | 0.0078 (11) | 0.0104 (14) | 0.0050 (10) | 0.0004 (10) | 0.0000 (10) | −0.0023 (10) |
O2 | 0.0096 (13) | 0.0026 (12) | 0.0089 (11) | 0.0013 (11) | −0.0022 (11) | 0.0000 (9) |
O3 | 0.0101 (12) | 0.0048 (14) | 0.0072 (12) | −0.0006 (10) | 0.0016 (10) | −0.0038 (10) |
Geometric parameters (Å, º) top
As1—O3i | 1.692 (3) | Mg2—O3ix | 2.017 (3) |
As1—O3ii | 1.692 (3) | Mg2—O3x | 2.017 (3) |
As1—O3 | 1.692 (3) | Mg2—O2xi | 2.080 (3) |
As1—O3iii | 1.692 (3) | Mg2—O2xii | 2.080 (3) |
As2—O2iv | 1.693 (2) | Mg2—O1 | 2.154 (3) |
As2—O2 | 1.693 (2) | Mg2—O1iv | 2.154 (3) |
As2—O1iv | 1.702 (3) | Na—O1vi | 2.321 (3) |
As2—O1 | 1.702 (3) | Na—O1xi | 2.321 (3) |
Mg1—O1v | 2.078 (3) | Na—O1xiii | 2.321 (3) |
Mg1—O1vi | 2.078 (3) | Na—O1 | 2.321 (3) |
Mg1—O3iii | 2.088 (3) | Na—O2xi | 2.710 (3) |
Mg1—O3vii | 2.088 (3) | Na—O2 | 2.710 (3) |
Mg1—O2 | 2.171 (3) | Na—O2xiii | 2.710 (3) |
Mg1—O2viii | 2.171 (3) | Na—O2vi | 2.710 (3) |
| | | |
O3i—As1—O3ii | 119.81 (18) | O2xi—Mg2—O1 | 92.98 (11) |
O3i—As1—O3 | 104.56 (8) | O2xii—Mg2—O1 | 92.57 (11) |
O3ii—As1—O3 | 104.56 (8) | O3ix—Mg2—O1iv | 91.27 (10) |
O3i—As1—O3iii | 104.56 (8) | O3x—Mg2—O1iv | 165.05 (12) |
O3ii—As1—O3iii | 104.56 (8) | O2xi—Mg2—O1iv | 92.57 (11) |
O3—As1—O3iii | 119.81 (18) | O2xii—Mg2—O1iv | 92.98 (11) |
O2iv—As2—O2 | 121.14 (19) | O1—Mg2—O1iv | 74.00 (15) |
O2iv—As2—O1iv | 104.82 (13) | O1vi—Na—O1xi | 104.14 (6) |
O2—As2—O1iv | 112.38 (13) | O1vi—Na—O1xiii | 120.77 (12) |
O2iv—As2—O1 | 112.38 (13) | O1xi—Na—O1xiii | 104.14 (6) |
O2—As2—O1 | 104.82 (13) | O1vi—Na—O1 | 104.14 (6) |
O1iv—As2—O1 | 99.24 (18) | O1xi—Na—O1 | 120.77 (12) |
O1v—Mg1—O1vi | 84.13 (16) | O1xiii—Na—O1 | 104.14 (6) |
O1v—Mg1—O3iii | 105.55 (11) | O1vi—Na—O2xi | 163.33 (8) |
O1vi—Mg1—O3iii | 93.11 (10) | O1xi—Na—O2xi | 64.10 (8) |
O1v—Mg1—O3vii | 93.11 (10) | O1xiii—Na—O2xi | 74.98 (8) |
O1vi—Mg1—O3vii | 105.55 (11) | O1—Na—O2xi | 74.81 (8) |
O3iii—Mg1—O3vii | 154.92 (16) | O1vi—Na—O2 | 74.98 (8) |
O1v—Mg1—O2 | 172.35 (11) | O1xi—Na—O2 | 74.81 (8) |
O1vi—Mg1—O2 | 92.80 (10) | O1xiii—Na—O2 | 163.33 (8) |
O3iii—Mg1—O2 | 81.57 (10) | O1—Na—O2 | 64.10 (8) |
O3vii—Mg1—O2 | 80.93 (11) | O2xi—Na—O2 | 90.01 (11) |
O1v—Mg1—O2viii | 92.80 (10) | O1vi—Na—O2xiii | 74.81 (8) |
O1vi—Mg1—O2viii | 172.35 (11) | O1xi—Na—O2xiii | 163.33 (8) |
O3iii—Mg1—O2viii | 80.93 (11) | O1xiii—Na—O2xiii | 64.10 (8) |
O3vii—Mg1—O2viii | 81.57 (10) | O1—Na—O2xiii | 74.98 (8) |
O2—Mg1—O2viii | 91.08 (15) | O2xi—Na—O2xiii | 120.00 (6) |
O3ix—Mg2—O3x | 103.55 (17) | O2—Na—O2xiii | 120.00 (6) |
O3ix—Mg2—O2xi | 90.13 (11) | O1vi—Na—O2vi | 64.10 (8) |
O3x—Mg2—O2xi | 85.57 (11) | O1xi—Na—O2vi | 74.98 (8) |
O3ix—Mg2—O2xii | 85.57 (11) | O1xiii—Na—O2vi | 74.81 (8) |
O3x—Mg2—O2xii | 90.13 (11) | O1—Na—O2vi | 163.33 (8) |
O2xi—Mg2—O2xii | 173.04 (19) | O2xi—Na—O2vi | 120.00 (6) |
O3ix—Mg2—O1 | 165.05 (12) | O2—Na—O2vi | 120.00 (6) |
O3x—Mg2—O1 | 91.27 (10) | O2xiii—Na—O2vi | 90.01 (11) |
Symmetry codes: (i) −y, x, −z; (ii) y, −x, −z; (iii) −x, −y, z; (iv) x, −y−3/2, −z+1/4; (v) −y−1, x−1, −z; (vi) y+1, −x, −z; (vii) x, y−1, z; (viii) −x, −y−1, z; (ix) x+1, −y−1/2, −z+1/4; (x) x+1, y−1, z; (xi) −x+1, −y−1, z; (xii) −x+1, y−1/2, −z+1/4; (xiii) −y, x−1, −z. |