A new NASICON-type chromium(III) phosphate, K0.16Na0.34Li2.5Cr2(PO4)3, lithium sodium potassium dichromate tris(phosphate), has been prepared by solid-state reaction. It consists of CrO6 octahedra and PO4 tetrahedra sharing corners to form a three-dimensional framework. The monovalent cations are located in the M1 (six-coordinate) and M2 (four-coordinate) sites of the framework. The M1 site is occupied by Na+ and K+ cations with 69 (3) and 31 (3)% occupancy, respectively. The Li+ ions, Li1 and Li2, are split over two M2 sites in general positions, with 60 (2) and 40 (2)% occupancy, respectively. Atom Li2 is disordered around a threefold inversion axis.
Supporting information
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (P-O) = 0.002 Å
- Disorder in solvent or counterion
- R factor = 0.025
- wR factor = 0.072
- Data-to-parameter ratio = 9.7
checkCIF/PLATON results
No syntax errors found
Alert level C
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical . ?
PLAT068_ALERT_1_C Reported F000 Differs from Calcd (or Missing)... ?
PLAT077_ALERT_4_C Unitcell contains non-integer number of atoms .. ?
PLAT088_ALERT_3_C Poor Data / Parameter Ratio .................... 9.67
PLAT199_ALERT_1_C Check the Reported _cell_measurement_temperature 293 K
PLAT200_ALERT_1_C Check the Reported _diffrn_ambient_temperature . 293 K
PLAT202_ALERT_3_C Isotropic non-H Atoms in Anion/Solvent ......... 1
PLAT302_ALERT_4_C Anion/Solvent Disorder ......................... 42.00 Perc.
Alert level G
CELLZ01_ALERT_1_G Difference between formula and atom_site contents detected.
CELLZ01_ALERT_1_G ALERT: check formula stoichiometry or atom site occupancies.
From the CIF: _cell_formula_units_Z 6
From the CIF: _chemical_formula_sum Cr2 K0.16 Li2.50 Na0.34 O12 P3
TEST: Compare cell contents of formula and atom_site data
atom Z*formula cif sites diff
Cr 12.00 12.00 0.00
K 0.96 0.93 0.03
Li 15.00 14.99 0.01
Na 2.04 2.07 -0.03
O 72.00 72.00 0.00
P 18.00 18.00 0.00
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
8 ALERT level C = Check and explain
2 ALERT level G = General alerts; check
6 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
2 ALERT type 3 Indicator that the structure quality may be low
2 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: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97.
Li
2.5Na
0.34K
0.16Cr
2(PO
4)
3 top
Crystal data top
Li2.5Na0.34K0.16Cr2(PO4)3 | Dx = 3.124 Mg m−3 |
Mr = 420.31 | Mo Kα radiation, λ = 0.71073 Å |
Hexagonal, R3 | Cell parameters from 25 reflections |
Hall symbol: -R 3 | θ = 10–16° |
a = 8.300 (2) Å | µ = 3.13 mm−1 |
c = 22.469 (5) Å | T = 293 K |
V = 1340.5 (5) Å3 | Hexagon, green |
Z = 6 | 0.15 × 0.12 × 0.08 mm |
F(000) = 1220 | |
Data collection top
Enraf–Nonius CAD-4 diffractometer | 572 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.027 |
Graphite monochromator | θmax = 26.9°, θmin = 2.7° |
ω/2θ scans | h = −10→9 |
Absorption correction: ψ scan (North et al., 1968) | k = 0→10 |
Tmin = 0.644, Tmax = 0.779 | l = −28→28 |
2047 measured reflections | 2 standard reflections every 120 min |
648 independent reflections | intensity decay: 1% |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.025 | w = 1/[σ2(Fo2) + (0.0328P)2 + 7.8382P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.072 | (Δ/σ)max < 0.001 |
S = 1.13 | Δρmax = 0.89 e Å−3 |
648 reflections | Δρmin = −0.48 e Å−3 |
67 parameters | Extinction correction: SHELXL97 (Sheldrick, 1997) |
2 restraints | Extinction coefficient: 0.0016 (4) |
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 | Occ. (<1) |
Cr1 | 0.6667 | 0.3333 | −0.02212 (3) | 0.0070 (3) | |
Cr2 | 0.6667 | 0.3333 | 0.18177 (4) | 0.0073 (3) | |
P | 0.66663 (10) | 0.62046 (10) | 0.08315 (3) | 0.0064 (2) | |
K | 0.0000 | 0.0000 | 0.0000 | 0.0406 (15) | 0.31 (3) |
Na | 0.0000 | 0.0000 | 0.0000 | 0.0406 (15) | 0.69 (3) |
O1 | 0.6759 (3) | 0.5335 (3) | 0.02513 (10) | 0.0171 (5) | |
O2 | 0.5368 (3) | 0.7028 (3) | 0.07835 (9) | 0.0114 (5) | |
O3 | 0.8649 (3) | 0.7770 (3) | 0.09910 (9) | 0.0111 (5) | |
O4 | 0.5811 (3) | 0.4765 (3) | 0.13478 (10) | 0.0145 (5) | |
Li1 | 0.3053 (13) | 0.3534 (13) | 0.1160 (4) | 0.006 (2)* | 0.504 (15) |
Li2 | 0.236 (2) | 0.565 (2) | 0.1678 (8) | 0.012 (5)* | 0.329 (15) |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cr1 | 0.0071 (3) | 0.0071 (3) | 0.0069 (4) | 0.00354 (15) | 0.000 | 0.000 |
Cr2 | 0.0066 (3) | 0.0066 (3) | 0.0086 (4) | 0.00328 (15) | 0.000 | 0.000 |
P | 0.0061 (4) | 0.0053 (4) | 0.0076 (4) | 0.0027 (3) | −0.0017 (3) | −0.0011 (2) |
K | 0.0572 (19) | 0.0572 (19) | 0.0075 (16) | 0.0286 (10) | 0.000 | 0.000 |
Na | 0.0572 (19) | 0.0572 (19) | 0.0075 (16) | 0.0286 (10) | 0.000 | 0.000 |
O1 | 0.0226 (13) | 0.0172 (12) | 0.0153 (11) | 0.0128 (11) | −0.0048 (10) | −0.0081 (9) |
O2 | 0.0118 (10) | 0.0135 (11) | 0.0127 (10) | 0.0093 (9) | −0.0041 (8) | −0.0030 (8) |
O3 | 0.0065 (10) | 0.0075 (10) | 0.0167 (10) | 0.0016 (8) | −0.0015 (8) | −0.0032 (8) |
O4 | 0.0103 (11) | 0.0146 (11) | 0.0190 (11) | 0.0065 (9) | 0.0017 (9) | 0.0078 (9) |
Geometric parameters (Å, º) top
Cr1—O1i | 1.940 (2) | P—O4 | 1.559 (2) |
Cr1—O1ii | 1.940 (2) | K—O3ii | 2.751 (2) |
Cr1—O1 | 1.940 (2) | K—O3ix | 2.751 (2) |
Cr1—O2iii | 2.008 (2) | K—O3x | 2.751 (2) |
Cr1—O2iv | 2.008 (2) | K—O3xi | 2.751 (2) |
Cr1—O2v | 2.008 (2) | K—O3xii | 2.751 (2) |
Cr2—O4ii | 1.968 (2) | K—O3v | 2.751 (2) |
Cr2—O4i | 1.968 (2) | Li1—O4 | 2.031 (10) |
Cr2—O4 | 1.968 (2) | Li1—O2ix | 1.983 (10) |
Cr2—O3vi | 1.999 (2) | Li1—O3ii | 1.991 (10) |
Cr2—O3vii | 1.999 (2) | Li1—O4viii | 2.221 (10) |
Cr2—O3viii | 1.999 (2) | Li2—O2ix | 2.145 (17) |
P—O1 | 1.511 (2) | Li2—O2xiii | 2.323 (19) |
P—O2 | 1.542 (2) | Li2—O2viii | 2.438 (19) |
P—O3 | 1.545 (2) | Li2—O4ix | 2.570 (19) |
| | | |
O1—P—O2 | 111.44 (13) | O3x—K—O3xi | 118.88 (7) |
O1—P—O3 | 108.35 (13) | O3ii—K—O3xii | 118.88 (7) |
O2—P—O3 | 109.28 (12) | O3ix—K—O3xii | 180.00 (11) |
O1—P—O4 | 112.85 (14) | O3x—K—O3xii | 61.12 (7) |
O2—P—O4 | 103.92 (12) | O3xi—K—O3xii | 118.88 (7) |
O3—P—O4 | 110.94 (12) | O3ii—K—O3v | 118.88 (7) |
O3ii—K—O3ix | 61.12 (7) | O3ix—K—O3v | 118.88 (7) |
O3ii—K—O3x | 180.00 (5) | O3x—K—O3v | 61.12 (7) |
O3ix—K—O3x | 118.88 (7) | O3xi—K—O3v | 180.00 (10) |
O3ii—K—O3xi | 61.12 (7) | O3xii—K—O3v | 61.12 (7) |
O3ix—K—O3xi | 61.12 (7) | | |
Symmetry codes: (i) −x+y+1, −x+1, z; (ii) −y+1, x−y, z; (iii) y, −x+y, −z; (iv) x−y+1, x, −z; (v) −x+1, −y+1, −z; (vi) x−y+2/3, x−2/3, −z+1/3; (vii) −x+5/3, −y+4/3, −z+1/3; (viii) y−1/3, −x+y+1/3, −z+1/3; (ix) −x+y, −x+1, z; (x) y−1, −x+y, −z; (xi) x−1, y−1, z; (xii) x−y, x−1, −z; (xiii) −x+2/3, −y+4/3, −z+1/3. |