Scheelite-type sodium neodymium(III) ortho-oxidomolybdate(VI), NaNd[MoO₄]₂

Scheelite-type NaNd[MoO₄]₂ contains one crystallographic position (site symmetry ) for the large cations, which is mixed-occupied by Na⁺ and Nd³⁺ cations in a 1:1 molar ratio. Thus, both are surrounded by eight O atoms in the shape of a trigonal dodeca­hedron. Furthermore, the structure consists of crystallographically unique [MoO₄]^2- units (site symmetry ) surrounded by eight sodium and neodymium cations, which are all vertex-attached. The polyhedra around the Na⁺/Nd³⁺ cations are connected to four others via common edges, building up a three-dimensional network in whose tetra­hedral voids of O atoms the Mo⁶⁺ cations reside.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](Mo-O) = 0.002 Å
• Disorder in main residue
• R factor = 0.020
• wR factor = 0.044
• Data-to-parameter ratio = 13.1

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT774_ALERT_1_C Suspect X-Y Bond in CIF:   NA     --  NA      ..       3.92 Ang.
PLAT774_ALERT_1_C Suspect X-Y Bond in CIF:   NA     --  ND      ..       3.92 Ang.
PLAT774_ALERT_1_C Suspect X-Y Bond in CIF:   NA     --  ND      ..       3.92 Ang.
PLAT774_ALERT_1_C Suspect X-Y Bond in CIF:   NA     --  NA      ..       3.92 Ang.

Alert level G
PLAT004_ALERT_5_G Info: Polymeric Structure Found with Dimension .          1
PLAT005_ALERT_5_G No _iucr_refine_instructions_details in CIF ....          ?
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported   _diffrn_ambient_temperature        293 K
PLAT232_ALERT_2_G Hirshfeld Test Diff (M-X)  Mo     --  O       ..       11.1 su
PLAT301_ALERT_3_G Note: Main Residue  Disorder ...................         17 Perc.
PLAT779_ALERT_4_G Suspect or Irrelevant (Bond) Angle in CIF .... #         75
              ND   -O    -NA     13.555   1.555  13.555              0.00 Deg.
PLAT779_ALERT_4_G Suspect or Irrelevant (Bond) Angle in CIF .... #         82
              NA   -O    -ND      5.554   1.555   5.554              0.00 Deg.
PLAT794_ALERT_5_G Note: Tentative Bond Valency for Mo      (VI)          5.76
PLAT811_ALERT_5_G No ADDSYM Analysis: Too Many Excluded Atoms ....          !

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   4 ALERT level C = Check. Ensure it is not caused by an omission or oversight
  10 ALERT level G = General information/check it is not something unexpected

   6 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 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
   2 ALERT type 4 Improvement, methodology, query or suggestion
   4 ALERT type 5 Informative message, check

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S1. Comment

Scheelite-type sodium lanthanide ortho-oxomolybdates of the formula NaLn[MoO₄]₂ are already known for Ln = La, Ce, and Er (see related literature). The structure features Na⁺ and Nd³⁺ cations together at the common Wyckoff position 4b, eightfold coordinated by O^2– anions in the shape of trigonal dodecahedra (Fig. 1). The Na : Nd ratio was fixed at a molar ratio of 1 : 1 for maintaining electroneutrality. A similar surrounding is found for the cationic coordination around the crystallographically unique isolated ortho-oxomolybdate anions [MoO₄]^2– with the Mo⁶⁺ cations at the Wyckoff position 4a (Fig. 2). The polyhedra around the Na⁺/Nd³⁺ cations are interconnected to four others via common edges building up a three-dimensional network, in whose voids of oxygen the Mo⁶⁺ cations are located (Fig. 3). Both the cations at the sites 4a (Na⁺ and Nd³⁺ in a 1:1 molar ratio) and 4b (Mo⁶⁺) arrange themselves in two interpenetrating diamond-like networks (Schustereit et al., 2011) as in the case of NaTl (Zintl & Dullenkopf, 1932).

Related literature

For isotypic NaLn[MoO₄]₂ structures, see: Stevens et al. (1991) and Teller (1992) for Ln = La; Teller (1992) for Ln = Ce; Zhao et al. (2010) for Ln = Er. For interpenetrating diamond-like networks, see: Schustereit et al. (2011). These were also obseverd in NaTl, see: Zintl & Dullenkopf (1932).

S2. Experimental

Pale violet, coarse single crystals of Scheelite-type NaNd[MoO₄]₂ were obtained as by-product in an unsuccessful attempt to synthesize NdF[MoO₄], using a mixture of NdF₃ and Na₂[MoO₄] in a 1:1 molar ratio, which was heated at 850 °C for 7 days in an evacuated, sealed, fused-silica ampoule.

Computing details

Data collection: COLLECT (Nonius, 1998); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. Trigonal dodecahedral oxygen environment of the Na^+/Nd^3+ cations in Scheelite-type NaNd[MoO4]2 (ellipsoids are drawn at 90 % probability level, symmetry codes: (i) y–1/4, –x+3/4, z+3/4;(ii) –y+1/4, x–1/4, z+3/4; (iii) x–1/2, y, –z+1/2; (iv) –x+1/2, –y+1/2, –z+1/2; (v) –y+3/4, x–1/4, –z+3/4; (vi) y–3/4, –x+3/4, –z+3/4; (vii) x–1/2, y–1/2, z+1/2; (viii) –x+1/2, –y+1, z+1/2)
	Fig. 2. Cationic surrounding of the isolated ortho-oxomolybdate(VI) tetrahedra [MoO4]^2– in Scheelite-type NaNd[MoO4]2 (ellipsoids are drawn at 90 % probability level, symmetry codes for O: x, y, z; (xi) –y+1/4, x+1/4, –z+1/4; (xii) y–1/4, –x+1/4, z+1/4; (xiii) –x, –y+1/2, z; symmetry codes for Na/Nd: (iii) x–1/2, y, –z+1/2; (iv) –x+1/2, –y+1/2, –z+1/2; (v) –y+3/4, x–1/4, –z+3/4; (vi) y–3/4, –x+3/4, –z+3/4; (vii) x–1/2, y–1/2, z+1/2; (ix) –x, –y, –z+1; (x) –x, –y+1, –z+1; (xiv) x+1/2, y+1/2, z–1/2)
	Fig. 3. View at the crystal structure of Scheelite-type NaNd[MoO4]2 along [010] (slightly rotated) with special emphasis on the edge-connected oxygen polyhedra around the Na^+ and Nd^3+ cations, respectively.

sodium neodymium(III) ortho-oxidomolybdate(vi)

Crystal data

NaNd[MoO4]2	Dx = 5.001 Mg m^−3
Mr = 487.11	Mo Kα radiation, λ = 0.71069 Å
Tetragonal, I41/a	Cell parameters from 2325 reflections
Hall symbol: -I 4ad	θ = 1.0–28.3°
a = 5.2871 (3) Å	µ = 11.79 mm^−1
c = 11.5729 (7) Å	T = 293 K
V = 323.50 (3) Å^3	Coarse transparent, pale violet
Z = 2	0.11 × 0.09 × 0.07 mm
F(000) = 438

Data collection

Nonius KappaCCD diffractometer	196 independent reflections
Radiation source: fine-focus sealed tube	135 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.058
ω and φ scans	θmax = 28.2°, θmin = 4.2°
Absorption correction: numerical (X-SHAPE; Stoe & Cie, 1995)	h = −6→6
Tmin = 0.273, Tmax = 0.434	k = −6→6
1026 measured reflections	l = −15→15

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.020	w = 1/[σ^2(Fo^2) + (0.0102P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.044	(Δ/σ)max < 0.001
S = 0.99	Δρmax = 0.45 e Å^−3
196 reflections	Δρmin = −0.42 e Å^−3
15 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0092 (8)

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Na	0.0000	0.2500	0.6250	0.0125 (2)	0.50
Nd	0.0000	0.2500	0.6250	0.0125 (2)	0.50
Mo	0.0000	0.2500	0.1250	0.0131 (2)
O	0.2406 (3)	0.3949 (3)	0.04140 (14)	0.0255 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Na	0.0130 (3)	0.0130 (3)	0.0113 (3)	0.000	0.000	0.000
Nd	0.0130 (3)	0.0130 (3)	0.0113 (3)	0.000	0.000	0.000
Mo	0.0122 (3)	0.0122 (3)	0.0151 (3)	0.000	0.000	0.000
O	0.0298 (10)	0.0227 (12)	0.0239 (9)	−0.0002 (8)	0.0022 (8)	−0.0008 (9)

Geometric parameters (Å, º)

Na—O^i	2.4851 (15)	Na—Nd^x	3.9191 (2)
Na—O^ii	2.4851 (15)	Na—Na^x	3.9191 (2)
Na—O^iii	2.4851 (15)	Mo—O^xi	1.7725 (16)
Na—O^iv	2.4851 (15)	Mo—O	1.7725 (17)
Na—O^v	2.5182 (18)	Mo—O^xii	1.7725 (16)
Na—O^vi	2.5182 (18)	Mo—O^xiii	1.7725 (16)
Na—O^vii	2.5182 (18)	O—Nd^iii	2.4851 (15)
Na—O^viii	2.5182 (18)	O—Na^iii	2.4851 (15)
Na—Na^ix	3.9191 (2)	O—Na^xiv	2.5182 (18)
Na—Nd^ix	3.9191 (2)	O—Nd^xiv	2.5182 (18)
O^i—Na—O^ii	126.90 (5)	O^vi—Na—Nd^ix	102.66 (4)
O^i—Na—O^iii	126.90 (5)	O^vii—Na—Nd^ix	85.20 (3)
O^ii—Na—O^iii	78.41 (7)	O^viii—Na—Nd^ix	130.62 (4)
O^i—Na—O^iv	78.41 (7)	Na^ix—Na—Nd^ix	0.0
O^ii—Na—O^iv	126.90 (5)	O^i—Na—Nd^x	38.74 (4)
O^iii—Na—O^iv	126.90 (5)	O^ii—Na—Nd^x	160.78 (4)
O^i—Na—O^v	151.28 (7)	O^iii—Na—Nd^x	101.53 (4)
O^ii—Na—O^v	68.38 (4)	O^iv—Na—Nd^x	68.65 (4)
O^iii—Na—O^v	76.88 (6)	O^v—Na—Nd^x	130.62 (4)
O^iv—Na—O^v	73.65 (3)	O^vi—Na—Nd^x	85.20 (3)
O^i—Na—O^vi	73.65 (3)	O^vii—Na—Nd^x	38.14 (3)
O^ii—Na—O^vi	76.88 (6)	O^viii—Na—Nd^x	102.66 (4)
O^iii—Na—O^vi	68.38 (4)	Na^ix—Na—Nd^x	123.025 (3)
O^iv—Na—O^vi	151.28 (7)	Nd^ix—Na—Nd^x	123.025 (3)
O^v—Na—O^vi	134.81 (8)	O^i—Na—Na^x	38.74 (4)
O^i—Na—O^vii	76.88 (6)	O^ii—Na—Na^x	160.78 (4)
O^ii—Na—O^vii	151.28 (7)	O^iii—Na—Na^x	101.53 (4)
O^iii—Na—O^vii	73.65 (3)	O^iv—Na—Na^x	68.65 (4)
O^iv—Na—O^vii	68.38 (4)	O^v—Na—Na^x	130.62 (4)
O^v—Na—O^vii	98.49 (3)	O^vi—Na—Na^x	85.20 (3)
O^vi—Na—O^vii	98.49 (3)	O^vii—Na—Na^x	38.14 (3)
O^i—Na—O^viii	68.38 (4)	O^viii—Na—Na^x	102.66 (4)
O^ii—Na—O^viii	73.65 (3)	Na^ix—Na—Na^x	123.025 (3)
O^iii—Na—O^viii	151.28 (7)	Nd^ix—Na—Na^x	123.025 (3)
O^iv—Na—O^viii	76.88 (6)	Nd^x—Na—Na^x	0.0
O^v—Na—O^viii	98.49 (3)	O^xi—Mo—O	113.83 (11)
O^vi—Na—O^viii	98.49 (3)	O^xi—Mo—O^xii	107.34 (5)
O^vii—Na—O^viii	134.81 (8)	O—Mo—O^xii	107.34 (5)
O^i—Na—Na^ix	160.78 (4)	O^xi—Mo—O^xiii	107.34 (5)
O^ii—Na—Na^ix	68.65 (4)	O—Mo—O^xiii	107.34 (5)
O^iii—Na—Na^ix	38.74 (4)	O^xii—Mo—O^xiii	113.83 (11)
O^iv—Na—Na^ix	101.53 (4)	Mo—O—Nd^iii	133.30 (9)
O^v—Na—Na^ix	38.14 (3)	Mo—O—Na^iii	133.30 (9)
O^vi—Na—Na^ix	102.66 (4)	Nd^iii—O—Na^iii	0.0
O^vii—Na—Na^ix	85.20 (3)	Mo—O—Na^xiv	120.23 (8)
O^viii—Na—Na^ix	130.62 (4)	Nd^iii—O—Na^xiv	103.12 (6)
O^i—Na—Nd^ix	160.78 (4)	Na^iii—O—Na^xiv	103.12 (6)
O^ii—Na—Nd^ix	68.65 (4)	Mo—O—Nd^xiv	120.23 (8)
O^iii—Na—Nd^ix	38.74 (4)	Nd^iii—O—Nd^xiv	103.12 (6)
O^iv—Na—Nd^ix	101.53 (4)	Na^iii—O—Nd^xiv	103.12 (6)
O^v—Na—Nd^ix	38.14 (3)	Na^xiv—O—Nd^xiv	0.0

Symmetry codes: (i) y−1/4, −x+3/4, z+3/4; (ii) x−1/2, y, −z+1/2; (iii) −x+1/2, −y+1/2, −z+1/2; (iv) −y+1/4, x−1/4, z+3/4; (v) x−1/2, y−1/2, z+1/2; (vi) −x+1/2, −y+1, z+1/2; (vii) −y+3/4, x−1/4, −z+3/4; (viii) y−3/4, −x+3/4, −z+3/4; (ix) −x, −y, −z+1; (x) −x+1/2, −y+1/2, −z+3/2; (xi) −x, −y+1/2, z; (xii) −y+1/4, x+1/4, −z+1/4; (xiii) y−1/4, −x+1/4, −z+1/4; (xiv) x+1/2, y+1/2, z−1/2.