Li_1,44Al_1,44Si_1,56O₆

The title compound, lithium aluminium silicon hexoxide, was prepared by a solid-state method. It has the β-quartz-type structure. Si⁴⁺ cations are replaced by Al³⁺ and the charge is compensated by the incorporation of Li⁺ into the main channel of the structure. The Al and Si atoms are disordered on a single site.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma]() = 0.000 Å
• Disorder in main residue
• R factor = 0.017
• wR factor = 0.051
• Data-to-parameter ratio = 10.3

checkCIF/PLATON results

No syntax errors found



Alert level A
GEOM005_ALERT_1_A  _geom_angle_atom_site_label_1 is missing
            Label identifying the atom site 1.
GEOM006_ALERT_1_A  _geom_angle_atom_site_label_2 is missing
            Label identifying the atom site 2.
PLAT043_ALERT_1_A Check Reported Molecular Weight ................     188.67
PLAT044_ALERT_1_A Calculated and Reported Dx Differ ..............          ?
PLAT051_ALERT_1_A Mu(calc) and Mu(CIF) Ratio Differs from 1.0 by .     261.54 Perc.
PLAT075_ALERT_1_A Occupancy       2.00 greater than 1.0 for ......          O

Alert level C
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT068_ALERT_1_C Reported F000 Differs from Calcd (or Missing)...          ?
PLAT077_ALERT_4_C Unitcell contains non-integer number of atoms ..          ?
PLAT127_ALERT_1_C Implicit Hall Symbol  Inconsistent with Explicit    P 62 2c (00-2
PLAT144_ALERT_4_C su on alpha    Small or Missing  (x 10000) .....          0 Deg.
PLAT145_ALERT_4_C su on beta     Small or Missing  (x 10000) .....          0 Deg.
PLAT146_ALERT_4_C su on gamma    Small or Missing  (x 10000) .....          0 Deg.
PLAT161_ALERT_4_C Missing or Zero su (esd) on x-coordinate for ...         SI
PLAT161_ALERT_4_C Missing or Zero su (esd) on x-coordinate for ...         AL
PLAT161_ALERT_4_C Missing or Zero su (esd) on x-coordinate for ...         LI
PLAT162_ALERT_4_C Missing or Zero su (esd) on y-coordinate for ...         SI
PLAT162_ALERT_4_C Missing or Zero su (esd) on y-coordinate for ...         AL
PLAT162_ALERT_4_C Missing or Zero su (esd) on y-coordinate for ...         LI
PLAT163_ALERT_4_C Missing or Zero su (esd) on z-coordinate for ...         SI
PLAT163_ALERT_4_C Missing or Zero su (esd) on z-coordinate for ...         AL
PLAT163_ALERT_4_C Missing or Zero su (esd) on z-coordinate for ...         LI
PLAT163_ALERT_4_C Missing or Zero su (esd) on z-coordinate for ...          O
PLAT301_ALERT_3_C Main Residue  Disorder .........................      25.00 Perc.
PLAT302_ALERT_4_C Anion/Solvent Disorder .........................      48.00 Perc.
PLAT751_ALERT_4_C Bond    Calc     2.05796, Rep  2.0579(15) ......  Senseless su
              LI   -O       1.555   1.544
PLAT751_ALERT_4_C Bond    Calc     2.05796, Rep  2.0579(15) ......  Senseless su
              O    -LI      1.555   1.566

Alert level G
REFLT03_ALERT_4_G  WARNING: Large fraction of Friedel related reflns may
                     be needed to determine absolute structure
           From the CIF: _diffrn_reflns_theta_max           29.39
           From the CIF: _reflns_number_total                134
           Count of symmetry unique reflns           99
           Completeness (_total/calc)            135.35%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured        35
           Fraction of Friedel pairs measured     0.354
           Are heavy atom types Z>Si present        yes

   6 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
  21 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   9 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
  18 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

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: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1998) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.

lithium aluminium silicon hexaoxide

Crystal data

Li1.44Al1.44Si1.56O6	Dx = 2.320 Mg m^−3
Mr = 188.67	Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P6222	Cell parameters from 25 reflections
Hall symbol: P 62 2c (00-2)	θ = 11.5–20.2°
a = 5.2654 (2) Å	µ = 0.75 mm^−1
c = 5.6240 (8) Å	T = 298 K
V = 135.03 (2) Å^3	Prism, colourless
Z = 1	0.15 × 0.12 × 0.06 mm
F(000) = 93

Data collection

Enraf–Nonius CAD-4 diffractometer	127 reflections with I > \2(I)
Radiation source: fine-focus sealed tube	Rint = 0.049
Graphite monochromator	θmax = 29.4°, θmin = 4.5°
ω/2θ scans	h = 0→6
Absorption correction: ψ scan (North et al., 1968)	k = 0→6
Tmin = 0.894, Tmax = 0.959	l = −7→7
876 measured reflections	2 standard reflections every 120 min
134 independent reflections	intensity decay: 3%

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)] = 0.017	w = 1/[σ^2(Fo^2) + (0.0146P)^2 + 0.0904P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.051	(Δ/σ)max < 0.001
S = 1.26	Δρmax = 0.16 e Å^−3
134 reflections	Δρmin = −0.23 e Å^−3
13 parameters	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.52 (6)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Si	0.5000	0.5000	0.3333	0.0062 (3)	0.52
Al	0.5000	0.5000	0.3333	0.0062 (3)	0.48
Li	0.0000	0.0000	0.0000	0.019 (2)	0.48
O	0.20088 (18)	0.79912 (18)	0.8333	0.0179 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Si	0.0064 (4)	0.0064 (4)	0.0061 (4)	0.0034 (4)	0.000	0.000
Al	0.0064 (4)	0.0064 (4)	0.0061 (4)	0.0034 (4)	0.000	0.000
Li	0.013 (4)	0.023 (7)	0.025 (5)	0.012 (4)	0.000	0.000
O	0.0163 (7)	0.0163 (7)	0.0240 (8)	0.0103 (7)	−0.0101 (6)	−0.0101 (6)

Bond lengths (Å)

Si—O^i	1.6769 (4)	Li—Si^xi	2.6327
Si—O^ii	1.6769 (4)	Li—Al^xii	2.6327
Si—O^iii	1.6769 (4)	Li—Al^xi	2.6327
Si—O^iv	1.6769 (4)	Li—Si^xii	2.6327
Si—Li^v	2.6327	Li—Al^xiii	3.2320 (2)
Si—Li^vi	2.6327	O—Al^xiv	1.6769 (5)
Li—Li^vii	1.8747 (3)	O—Si^xiv	1.6769 (5)
Li—Li^vi	1.8747 (3)	O—Si^xv	1.6769 (5)
Li—O^i	2.0579 (15)	O—Al^xv	1.6769 (5)
Li—O^viii	2.0579 (15)	O—Li^xvi	2.0579 (15)
Li—O^ix	2.0579 (15)	O—Li^xvii	2.0579 (15)
Li—O^x	2.0579 (15)

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