X-ray powder diffraction study of LiCrP₂O₇

The monoclinic crystal structure of lithium chromium(III) diphosphate, LiCrP₂O₇, isotypic with other members of the series LiM^IIIP₂O₇ (M^III = Mn, Fe, V, Mo, Sc and In), was refined from laboratory X-ray powder diffraction data using the Rietveld method. The Cr³⁺ cation is bonded to six O atoms from five diphosphate anions to form a distorted octa­hedron. Links between the bent diphosphate anions and the Cr³⁺ cations result in a three-dimensional network, with tunnels filled by the Li⁺ cations in a considerably distorted tetra­hedral environment of O atoms.

Key indicators

• Powder X-ray study
• T = 295 K
• Mean [sigma](P-O) = 0.015 Å
• R factor = 0.000
• wR factor = 0.000
• Data-to-parameter ratio = 0.0

checkCIF/PLATON results

No syntax errors found



Alert level C
REFI023_ALERT_1_C  _refine_diff_density_max is missing
            Maximum value of final difference map (e A-3).
            The following tests will not be performed
            DIFMN_01,DIFMX_01,DIFMX_02
REFI024_ALERT_1_C  _refine_diff_density_min is missing
            Minimum value of final difference map (e A-3).
            The following tests will not be performed
            DIFMN_01,DIFMN_02,DIFMN_03
PLAT162_ALERT_4_C Missing or Zero su (esd) on y-coordinate for ...         CR

Alert level G
PLAT791_ALERT_1_G Confirm the Absolute Configuration of P1     = .          R
PLAT791_ALERT_1_G Confirm the Absolute Configuration of P2     = .          R

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

   4 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
   0 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: local program; cell refinement: FULLPROF (Rodríguez-Carvajal, 2001); data reduction: local program; program(s) used to solve structure: coordinates taken from an isotypic compound (Ivashkevich et al., 2006); program(s) used to refine structure: FULLPROF; molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: FULLPROF and PLATON (Spek, 2003).

Lithium chromium(III) diphosphate(V)

Crystal data

LiCrP2O7	V = 249.32 (6) Å^3
Mr = 232.88	Z = 2
Monoclinic, P21	Dx = 3.102 Mg m^−3
Hall symbol: P 2yb	Cu Kα radiation, λ = 1.54180 Å
a = 6.9019 (10) Å	T = 295 K
b = 7.9919 (11) Å	colourless
c = 4.7807 (7) Å	flat_sheet, 30 × 30 mm
β = 109.003 (4)°	Specimen preparation: Prepared at 295 K

Data collection

Carl Zeiss HZG-4A diffractometer	Data collection mode: reflection
Radiation source: fine-focus sealed X-ray tube, BSV-29	Scan method: step
Specimen mounting: packed powder pellet	2θmin = 12.00°, 2θmax = 100.00°, 2θstep = 0.02°

Refinement

Refinement on Inet	51 parameters
Least-squares matrix: full with fixed elements per cycle	12 restraints
Rp = 0.029	0 constraints
Rwp = 0.038	Weighting scheme based on measured s.u.'s w = 1/σ(Yobs)
Rexp = 0.101	(Δ/σ)max = 0.02
RBragg = 0.064	Background function: Polynomial background function, with six polynomial coefficients refined
Excluded region(s): none	Preferred orientation correction: none
Profile function: pseudo-Voigt profile function, η = 0.61(6)

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cr	0.2277 (13)	0.25000	0.216 (2)	0.0050*
P1	0.4190 (4)	0.4669 (3)	0.7984 (5)	0.0050*
P2	0.0196 (4)	0.5654 (3)	0.4005 (5)	0.0050*
O1	0.422 (4)	0.3125 (19)	0.611 (4)	0.0095*
O2	0.6216 (9)	0.5652 (9)	0.869 (5)	0.0095*
O3	0.351 (4)	0.427 (3)	1.065 (3)	0.0095*
O4	0.006 (3)	0.3996 (9)	0.254 (2)	0.0095*
O6	−0.0177 (16)	0.711 (2)	0.192 (4)	0.0095*
O5	−0.116 (3)	0.5673 (11)	0.602 (4)	0.0095*
O7	0.2562 (9)	0.5994 (9)	0.589 (4)	0.0095*
Li	0.8226 (9)	0.3780 (6)	0.8219 (11)	0.0250*

Geometric parameters (Å, º)

Cr—O1	1.99 (2)	P1—O7	1.629 (12)
Cr—O4	1.996 (19)	P2—O4	1.487 (8)
Cr—O3^i	1.91 (3)	P2—O5	1.55 (2)
Cr—O6^ii	2.040 (19)	P2—O6	1.499 (17)
Cr—O5^iii	1.980 (16)	P2—O7	1.611 (12)
Cr—O2^iv	1.924 (11)	Li—O2	2.102 (12)
P1—O1	1.529 (17)	Li—O4^v	2.049 (11)
P1—O2	1.542 (11)	Li—O6^iv	1.912 (16)
P1—O3	1.53 (2)	Li—O5^vi	1.966 (17)
O1—Cr—O4	93.6 (8)	O3—P1—O7	108.1 (11)
O1—Cr—O3^i	85.8 (8)	O4—P2—O5	110.1 (8)
O1—Cr—O6^ii	174.0 (7)	O4—P2—O6	114.1 (8)
O1—Cr—O5^iii	90.4 (9)	O4—P2—O7	108.1 (8)
O1—Cr—O2^iv	98.6 (10)	O5—P2—O6	113.5 (7)
O3^i—Cr—O4	92.3 (9)	O5—P2—O7	111.0 (9)
O4—Cr—O6^ii	81.5 (6)	O6—P2—O7	99.5 (7)
O4—Cr—O5^iii	89.0 (7)	P1—O7—P2	127.2 (5)
O2^iv—Cr—O4	164.1 (7)	O2—Li—O4^v	92.6 (8)
O3^i—Cr—O6^ii	91.0 (7)	O2—Li—O5^vi	76.9 (12)
O3^i—Cr—O5^iii	176.1 (10)	O2—Li—O6^iv	175.8 (12)
O2^iv—Cr—O3^i	98.7 (9)	O4^v—Li—O5^vi	107.7 (11)
O5^iii—Cr—O6^ii	92.9 (8)	O4^v—Li—O6^iv	83.3 (10)
O2^iv—Cr—O6^ii	86.9 (8)	O5^vi—Li—O6^iv	104.0 (8)
O2^iv—Cr—O5^iii	80.9 (6)	Cr—O1—P1	128.7 (14)
O1—P1—O2	110.8 (12)	Cr^vii—O2—P1	149.2 (12)
O1—P1—O3	112.8 (12)	Cr^viii—O3—P1	140.0 (13)
O1—P1—O7	107.6 (9)	Cr—O4—P2	130.1 (12)
O2—P1—O3	115.2 (12)	Cr^ix—O5—P2	133.0 (7)
O2—P1—O7	101.4 (6)	Cr^x—O6—P2	132.0 (10)
O4—Cr—O1—P1	−19.8 (18)	O7—P1—O2—Cr^vii	−15 (2)
O3^i—Cr—O1—P1	72.2 (18)	O1—P1—O3—Cr^viii	−12 (3)
O5^iii—Cr—O1—P1	−108.8 (17)	O2—P1—O3—Cr^viii	−141 (2)
O2^iv—Cr—O1—P1	170.3 (16)	O7—P1—O3—Cr^viii	106 (2)
O1—Cr—O4—P2	34.4 (10)	O1—P1—O7—P2	54.3 (16)
O3^i—Cr—O4—P2	−51.6 (10)	O2—P1—O7—P2	170.7 (12)
O6^ii—Cr—O4—P2	−142.2 (9)	O3—P1—O7—P2	−67.7 (15)
O5^iii—Cr—O4—P2	124.7 (9)	O5—P2—O4—Cr	−131.8 (11)
O1—Cr—O3^i—P1^i	141 (2)	O6—P2—O4—Cr	99.3 (9)
O4—Cr—O3^i—P1^i	−126 (2)	O7—P2—O4—Cr	−10.3 (11)
O4—Cr—O6^ii—P2^ii	−152.9 (12)	O4—P2—O5—Cr^ix	−162.7 (14)
O1—Cr—O5^iii—P2^iii	71.2 (17)	O6—P2—O5—Cr^ix	−33.4 (19)
O4—Cr—O5^iii—P2^iii	−22.4 (16)	O7—P2—O5—Cr^ix	77.6 (16)
O1—Cr—O2^iv—P1^iv	−15 (2)	O4—P2—O6—Cr^x	42.1 (15)
O2—P1—O1—Cr	−122.9 (17)	O5—P2—O6—Cr^x	−85.1 (14)
O3—P1—O1—Cr	106.3 (17)	O7—P2—O6—Cr^x	156.9 (11)
O7—P1—O1—Cr	−12.8 (19)	O4—P2—O7—P1	−43.1 (13)
O1—P1—O2—Cr^vii	99.6 (19)	O5—P2—O7—P1	77.8 (11)
O3—P1—O2—Cr^vii	−131 (2)	O6—P2—O7—P1	−162.4 (12)

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