Crystal structure of a layered phosphate molybdate K₂Gd(PO₄)(MoO₄)

Dipotassium gadolinium(III) phosphate(V) molybdate(VI), synthesized from a high-temperature melt starting from GdF₃ as a source of gadolinium, has a structure that is isotypic with other M^I₂M^III(M^VIO₄)(PO₄) compounds, where M^I = Na, K or Cs, and M^III = rare-earth cation, M^VI = Mo or W. The three-dimensional framework is built up from [Gd(PO₄)(MoO₄)] anionic sheets, which are organized by adhesion of [GdPO₄] layers and [MoO₄] tetra­hedra stacked above and below of these layers, and the inter­stitial space is occupied by K cations having eightfold oxygen coordination.

Key indicators

Structure: I

• Single-crystal X-ray study
• T = 200 K
• Mean [sigma](d-O) = 0.002 Å
• R factor = 0.017
• wR factor = 0.045
• Data-to-parameter ratio = 17.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT042_ALERT_1_C Calc. and Reported MoietyFormula Strings  Differ     Please Check
              Calc: Gd4 Mo4 O32 P4, 8(K)
              Rep.: Gd K2 Mo O8 P
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.39 Report
PLAT975_ALERT_2_C Check Calcd Resid. Dens.  0.46Ang From O2      .       0.45 eA-3
PLAT975_ALERT_2_C Check Calcd Resid. Dens.  0.76Ang From O2      .       0.44 eA-3
PLAT975_ALERT_2_C Check Calcd Resid. Dens.  0.55Ang From O2      .       0.44 eA-3
PLAT975_ALERT_2_C Check Calcd Resid. Dens.  0.74Ang From O3      .       0.41 eA-3

Alert level G
PLAT004_ALERT_5_G Polymeric Structure Found with Maximum Dimension          1 Info
PLAT045_ALERT_1_G Calculated and Reported Z Differ by a Factor ...      0.250 Check
PLAT083_ALERT_2_G SHELXL Second Parameter in WGHT  Unusually Large       6.02 Why ?
PLAT794_ALERT_5_G Tentative Bond Valency for Gd1       (III)     .       3.35 Info
PLAT794_ALERT_5_G Tentative Bond Valency for Mo1       (VI)      .       5.82 Info
PLAT802_ALERT_4_G CIF Input Record(s) with more than 80 Characters          2 Info
PLAT910_ALERT_3_G Missing # of FCF Reflection(s) Below Theta(Min).          1 Note
                0  2  0,
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600        134 Note
PLAT933_ALERT_2_G Number of HKL-OMIT Records in Embedded .res File          1 Note
                2  0  0,
PLAT969_ALERT_5_G The 'Henn et al.' R-Factor-gap value ...........       2.19 Note
              Predicted wR2: Based on SigI   2  2.06 or SHELX Weight  4.11       

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   6 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

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   7 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

---

Computing details

Dipotassium gadolinium(III) phosphate(V) molybdate(VI)

Crystal data

K2Gd(PO4)(MoO4)	Dx = 3.881 Mg m^−3
Mr = 490.36	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Ibca	Cell parameters from 4624 reflections
a = 6.9527 (2) Å	θ = 3.3–30.0°
b = 19.7112 (6) Å	µ = 10.52 mm^−1
c = 12.2466 (3) Å	T = 200 K
V = 1678.35 (8) Å^3	Plate, clear light colourless
Z = 8	0.10 × 0.08 × 0.02 mm
F(000) = 1784

Data collection

XtaLAB Synergy, Dualflex, HyPix diffractometer	1079 independent reflections
Radiation source: micro-focus sealed X-ray tube, PhotonJet (Mo) X-ray Source	999 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.026
Detector resolution: 10 pixels mm^-1	θmax = 30.2°, θmin = 3.3°
ω scans	h = −8→8
Absorption correction: gaussian (CrysAlisPro; Rigaku OD, 2020)	k = −26→26
Tmin = 0.422, Tmax = 1.000	l = −16→16
6547 measured reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Primary atom site location: dual
R[F^2 > 2σ(F^2)] = 0.017	Secondary atom site location: difference Fourier map
wR(F^2) = 0.045	w = 1/[σ^2(Fo^2) + (0.0204P)^2 + 6.0211P] where P = (Fo^2 + 2Fc^2)/3
S = 1.13	(Δ/σ)max < 0.001
1079 reflections	Δρmax = 1.53 e Å^−3
61 parameters	Δρmin = −0.64 e Å^−3

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.

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

	x	y	z	Uiso*/Ueq
Gd1	1.000000	0.250000	0.42488 (2)	0.00554 (8)
Mo1	0.750000	0.41682 (2)	0.500000	0.00954 (10)
K1	0.71711 (11)	0.09429 (4)	0.32974 (5)	0.01672 (16)
P1	0.500000	0.250000	0.32047 (8)	0.0060 (2)
O1	0.6709 (3)	0.24105 (10)	0.40045 (17)	0.0095 (4)
O2	0.4787 (3)	0.18814 (11)	0.24608 (17)	0.0094 (4)
O3	0.9564 (3)	0.36581 (11)	0.47067 (18)	0.0139 (4)
O4	0.8056 (4)	0.46677 (12)	0.61376 (19)	0.0204 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Gd1	0.00341 (13)	0.00828 (12)	0.00493 (11)	−0.00007 (6)	0.000	0.000
Mo1	0.0102 (2)	0.00749 (16)	0.01089 (17)	0.000	0.00090 (13)	0.000
K1	0.0158 (4)	0.0130 (3)	0.0213 (3)	0.0014 (3)	−0.0007 (3)	0.0027 (2)
P1	0.0038 (6)	0.0093 (5)	0.0047 (5)	0.0000 (3)	0.000	0.000
O1	0.0037 (11)	0.0172 (10)	0.0076 (9)	0.0001 (8)	0.0006 (8)	0.0003 (8)
O2	0.0101 (11)	0.0110 (10)	0.0070 (9)	−0.0009 (8)	−0.0016 (7)	−0.0012 (8)
O3	0.0129 (11)	0.0111 (10)	0.0178 (11)	−0.0004 (9)	0.0034 (9)	−0.0019 (9)
O4	0.0209 (13)	0.0177 (11)	0.0226 (12)	0.0014 (10)	−0.0022 (10)	−0.0108 (10)

Geometric parameters (Å, º)

Gd1—O1	2.314 (2)	K1—O1	3.037 (2)
Gd1—O1^i	2.314 (2)	K1—O2	2.687 (2)
Gd1—O1^ii	2.453 (2)	K1—O2^iv	2.755 (2)
Gd1—O1^iii	2.453 (2)	K1—O3^i	2.958 (2)
Gd1—O2^iv	2.427 (2)	K1—O3^vi	3.143 (2)
Gd1—O2^v	2.427 (2)	K1—O4^vii	2.970 (3)
Gd1—O3	2.370 (2)	K1—O4^viii	2.679 (2)
Gd1—O3^i	2.370 (2)	K1—O4^vi	3.180 (3)
Mo1—O3^ii	1.788 (2)	P1—O1	1.550 (2)
Mo1—O3	1.788 (2)	P1—O1^ix	1.550 (2)
Mo1—O4	1.749 (2)	P1—O2^ix	1.529 (2)
Mo1—O4^ii	1.749 (2)	P1—O2	1.529 (2)
O1—Gd1—O1^iii	126.66 (6)	O4^ii—Mo1—O4	111.50 (16)
O1^i—Gd1—O1^iii	68.18 (8)	O1—K1—O3^vi	58.59 (6)
O1—Gd1—O1^i	165.14 (10)	O1—K1—O4^vi	101.73 (6)
O1^iii—Gd1—O1^ii	58.64 (10)	O2—K1—O2^iv	79.43 (6)
O1^i—Gd1—O1^ii	126.66 (6)	O2^iv—K1—O3^i	60.76 (6)
O1—Gd1—O1^ii	68.18 (8)	O2^iv—K1—O3^vi	118.34 (6)
O1^i—Gd1—O2^v	77.86 (7)	O2—K1—O3^vi	76.61 (6)
O1—Gd1—O2^iv	77.86 (7)	O2—K1—O3^i	120.86 (7)
O1^i—Gd1—O2^iv	89.27 (7)	O2—K1—O4^vi	77.78 (6)
O1—Gd1—O2^v	89.27 (7)	O2^iv—K1—O4^vi	157.11 (7)
O1—Gd1—O3	88.71 (8)	O2^iv—K1—O4^vii	80.51 (7)
O1^i—Gd1—O3	94.81 (8)	O2—K1—O4^vii	93.86 (7)
O1^i—Gd1—O3^i	88.71 (8)	O3^i—K1—O1	70.21 (6)
O1—Gd1—O3^i	94.81 (8)	O3^i—K1—O3^vi	85.55 (7)
O2^v—Gd1—O1^ii	144.86 (7)	O3^vi—K1—O4^vi	53.60 (6)
O2^v—Gd1—O1^iii	133.34 (7)	O3^i—K1—O4^vii	117.92 (7)
O2^iv—Gd1—O1^iii	144.86 (7)	O3^i—K1—O4^vi	131.61 (7)
O2^iv—Gd1—O1^ii	133.34 (7)	O4^vii—K1—O1	131.43 (6)
O2^iv—Gd1—O2^v	60.80 (10)	O4^viii—K1—O1	147.62 (7)
O3^i—Gd1—O1^ii	77.67 (7)	O4^viii—K1—O2^iv	124.43 (7)
O3—Gd1—O1^iii	77.67 (7)	O4^viii—K1—O2	152.41 (7)
O3^i—Gd1—O1^iii	78.52 (7)	O4^viii—K1—O3^vi	99.58 (7)
O3—Gd1—O1^ii	78.52 (7)	O4^viii—K1—O3^i	85.55 (7)
O3—Gd1—O2^v	74.22 (7)	O4^vii—K1—O3^vi	155.97 (7)
O3^i—Gd1—O2^iv	74.22 (7)	O4^vii—K1—O4^vi	103.12 (7)
O3^i—Gd1—O2^v	132.85 (7)	O4^viii—K1—O4^vii	78.60 (7)
O3—Gd1—O2^iv	132.85 (7)	O4^viii—K1—O4^vi	78.20 (5)
O3^i—Gd1—O3	152.63 (11)	O1^ix—P1—O1	101.63 (17)
O3—Mo1—O3^ii	111.59 (14)	O2—P1—O1	111.11 (11)
O4—Mo1—O3	107.39 (11)	O2^ix—P1—O1^ix	111.11 (11)
O4—Mo1—O3^ii	109.51 (11)	O2—P1—O1^ix	113.12 (11)
O4^ii—Mo1—O3	109.50 (11)	O2^ix—P1—O1	113.12 (11)
O4^ii—Mo1—O3^ii	107.39 (11)	O2^ix—P1—O2	106.87 (17)
O1^ix—P1—O1—Gd1	−156.6 (3)	O2^ix—P1—O2—K1	133.88 (11)
O1^ix—P1—O1—Gd1^ii	−0.001 (1)	O2^ix—P1—O2—K1^x	−106.9 (2)
O1^ix—P1—O1—K1	112.05 (8)	O2^ix—P1—O2—P1^ix	0 (100)
O1^ix—P1—O1—P1^ix	0 (100)	O3^ii—Mo1—O3—Gd1	15.95 (10)
O1—P1—O2—Gd1^v	−123.85 (10)	O3^ii—Mo1—O3—K1^iii	−114.91 (9)
O1^ix—P1—O2—Gd1^v	122.59 (11)	O3^ii—Mo1—O3—K1^i	152.13 (15)
O1^ix—P1—O2—K1^x	15.7 (2)	O3^ii—Mo1—O4—K1^xi	32.18 (14)
O1—P1—O2—K1^x	129.30 (18)	O3—Mo1—O4—K1^xii	143.40 (15)
O1^ix—P1—O2—K1	−103.53 (11)	O3^ii—Mo1—O4—K1^xii	−95.27 (17)
O1—P1—O2—K1	10.03 (14)	O3—Mo1—O4—K1^xi	−89.15 (12)
O1—P1—O2—P1^ix	0 (78)	O3^ii—Mo1—O4—K1^iii	116.29 (10)
O1^ix—P1—O2—P1^ix	0 (100)	O3—Mo1—O4—K1^iii	−5.05 (11)
O2—P1—O1—Gd1^ii	−120.61 (11)	O4^ii—Mo1—O3—Gd1	−102.81 (16)
O2^ix—P1—O1—Gd1	−37.5 (3)	O4—Mo1—O3—Gd1	135.96 (16)
O2^ix—P1—O1—Gd1^ii	119.18 (11)	O4—Mo1—O3—K1^i	−87.85 (14)
O2—P1—O1—Gd1	82.7 (2)	O4^ii—Mo1—O3—K1^iii	126.33 (10)
O2^ix—P1—O1—K1	−128.76 (10)	O4^ii—Mo1—O3—K1^i	33.37 (16)
O2—P1—O1—K1	−8.56 (12)	O4—Mo1—O3—K1^iii	5.11 (11)
O2—P1—O1—P1^ix	0 (100)	O4^ii—Mo1—O4—K1^xi	150.89 (14)
O2^ix—P1—O1—P1^ix	0 (23)	O4^ii—Mo1—O4—K1^iii	−125.01 (10)
O2^ix—P1—O2—Gd1^v	0.000 (1)	O4^ii—Mo1—O4—K1^xii	23.44 (10)

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