The type IV polymorph of KEu(PO(3))(4).

Single crystals of KEu(PO(3))(4), potassium europium(III) polyphosphate, were obtained by solid-state reactions. This monoclinic form is the second polymorph described for this composition and belongs to type IV of long-chain polyphosphates with general formula A(I)B(III)(PO(3))(4). It is isotypic with its KEr(PO(3))(4) and KDy(PO(3))(4) homologues. The crystal structure is built of infinite helical chains of corner-sharing PO(4) tetra-hedra with a repeating unit of eight tetra-hedra. These chains are further linked by isolated EuO(8) square anti-prisms, forming a three-dimensional framework. The K(+) ions are located in pseudo-hexa-gonal channels running along [01] and are surrounded by nine O atoms in a distorted environment.

Related literature

Besides crystals of the title compound, crystals of the type III polymorph (Hu et al., 1984 ▶)) have also been obtained. For isotypic AB(PO3)4 structures, where A is an alkali metal, Tl or NH4 +, and B is a rare earth element, see: Palkina et al. (1977 ▶) for TlNd; Maksimova et al. (1978 ▶) for RbNd; Dago et al. (1980 ▶) for KEr; Maksimova et al. (1981 ▶) for CsNd; Maksimova et al. (1982 ▶) for RbHo; Horchani et al. (2004 ▶) for RbEr; Rekik et al. (2004 ▶) for KGd; Naïli & Mhiri (2005 ▶) for CsGd; Ben Zarkouna et al. (2006 ▶) for (NH4)Gd; Khlissa & Férid (2006 ▶) for RbTb; Ettis et al. (2006 ▶) for RbGd; Chehimi-Moumen & Férid (2007 ▶) for KDy; Horchani-Naifer & Férid (2007 ▶) for CsPr; Zhu et al. (2009 ▶) for CsEu. For a review on the crystal chemisty of polyphosphates, see: Durif (1995 ▶). Jaouadi et al. (2003 ▶) have discussed the main crystal chemical characteristics of the seven AB(PO3)4 structure types. For applications of rare earth polyphosphates, see: Rashchi & Finch (2000 ▶); Barsukov et al. (2004 ▶). For general background, see: Porai-Koshits & Aslanov (1972 ▶). For ionic radii, see: Shannon (1976 ▶).

Experimental

Crystal data

KEu(PO3)4

M = 506.94

Monoclinic,

a = 10.3723 (1) Å

b = 8.9721 (1) Å

c = 10.8320 (1) Å

β = 106.053 (1)°

V = 968.73 (2) Å3

Z = 4

Mo Kα radiation

μ = 7.63 mm−1

T = 296 K

0.12 × 0.11 × 0.10 mm

Data collection

Bruker APEXII CCD diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T min = 0.466, T max = 0.513

24299 measured reflections

6201 independent reflections

5023 reflections with I > 2σ(I)

R int = 0.045

Refinement

R[F 2 > 2σ(F 2)] = 0.030

wR(F 2) = 0.072

S = 1.04

6201 reflections

163 parameters

Δρmax = 1.72 e Å−3

Δρmin = −2.04 e Å−3

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 1999 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809048788/wm2282sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809048788/wm2282Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

KEu(PO3)4	F(000) = 952
Mr = 506.94	Dx = 3.476 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 6203 reflections
a = 10.3723 (1) Å	θ = 2.6–40.6°
b = 8.9721 (1) Å	µ = 7.63 mm−1
c = 10.8320 (1) Å	T = 296 K
β = 106.053 (1)°	Hexagonal prism, colourless
V = 968.73 (2) Å3	0.12 × 0.11 × 0.10 mm
Z = 4

Bruker APEXII CCD diffractometer	6201 independent reflections
Radiation source: fine-focus sealed tube	5023 reflections with I > 2σ(I)
graphite	Rint = 0.045
Detector resolution: 8.3333 pixels mm-1	θmax = 40.6°, θmin = 3.1°
ω and φ scans	h = −18→18
Absorption correction: multi-scan (SADABS; Bruker, 2008)	k = −16→16
Tmin = 0.466, Tmax = 0.513	l = −19→5
24299 measured reflections

Refinement on F2	0 constraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F2 > 2σ(F2)] = 0.030	Secondary atom site location: difference Fourier map
wR(F2) = 0.072	w = 1/[σ2(Fo2) + (0.0311P)2 + 1.1689P] where P = (Fo2 + 2Fc2)/3
S = 1.04	(Δ/σ)max = 0.002
6201 reflections	Δρmax = 1.72 e Å−3
163 parameters	Δρmin = −2.04 e Å−3
0 restraints

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.

	x	y	z	Uiso*/Ueq
K	0.79467 (11)	0.57090 (14)	0.04227 (10)	0.0395 (2)
Eu	0.500385 (11)	0.772652 (13)	0.184899 (12)	0.00645 (3)
P1	0.85428 (6)	0.90558 (7)	0.24010 (7)	0.00615 (10)
P2	0.54001 (6)	0.82848 (7)	−0.14102 (7)	0.00607 (10)
P3	0.24938 (6)	1.02436 (7)	0.22927 (6)	0.00609 (10)
P4	0.17657 (6)	0.89469 (7)	−0.01962 (6)	0.00626 (10)
O1	0.14215 (17)	0.9549 (2)	0.10673 (19)	0.0085 (3)
O2	0.35389 (19)	0.9131 (2)	0.29039 (19)	0.0093 (3)
O3	−0.02278 (19)	0.7943 (2)	0.2518 (2)	0.0103 (3)
O4	0.6017 (2)	0.5368 (2)	0.1754 (2)	0.0117 (3)
O5	0.5648 (2)	0.7615 (2)	−0.0114 (2)	0.0117 (3)
O6	0.17180 (19)	1.0919 (2)	0.3112 (2)	0.0106 (3)
O7	0.73783 (19)	0.8192 (2)	0.2547 (2)	0.0134 (4)
O8	0.5691 (2)	0.7074 (2)	0.4090 (2)	0.0114 (3)
O9	0.31707 (19)	0.8419 (2)	0.0175 (2)	0.0121 (3)
O10	0.53947 (19)	1.0334 (2)	0.1765 (2)	0.0121 (3)
O11	0.31589 (17)	1.1548 (2)	0.1668 (2)	0.0092 (3)
O12	0.8309 (2)	0.9497 (2)	0.0936 (2)	0.0125 (3)

	U11	U22	U33	U12	U13	U23
K	0.0363 (5)	0.0581 (6)	0.0243 (4)	0.0047 (4)	0.0085 (4)	−0.0045 (4)
Eu	0.00596 (4)	0.00617 (4)	0.00701 (5)	0.00051 (3)	0.00144 (3)	0.00084 (4)
P1	0.0054 (2)	0.0053 (2)	0.0068 (2)	−0.00011 (17)	0.0002 (2)	0.00105 (19)
P2	0.0060 (2)	0.0053 (2)	0.0071 (2)	−0.00059 (17)	0.0021 (2)	−0.00025 (19)
P3	0.0057 (2)	0.0065 (2)	0.0062 (3)	0.00066 (17)	0.0020 (2)	−0.00024 (19)
P4	0.0052 (2)	0.0077 (2)	0.0050 (2)	−0.00047 (17)	0.00004 (19)	0.00081 (19)
O1	0.0071 (6)	0.0106 (7)	0.0078 (7)	−0.0029 (5)	0.0023 (6)	−0.0027 (6)
O2	0.0094 (7)	0.0093 (7)	0.0087 (8)	0.0032 (5)	0.0015 (6)	0.0013 (6)
O3	0.0108 (7)	0.0104 (7)	0.0101 (8)	0.0053 (6)	0.0036 (6)	0.0047 (6)
O4	0.0163 (8)	0.0086 (7)	0.0117 (8)	0.0013 (6)	0.0063 (7)	0.0015 (6)
O5	0.0135 (8)	0.0155 (8)	0.0074 (8)	0.0021 (6)	0.0048 (7)	0.0014 (6)
O6	0.0114 (7)	0.0126 (7)	0.0095 (8)	0.0022 (6)	0.0059 (7)	−0.0018 (6)
O7	0.0073 (7)	0.0148 (8)	0.0173 (10)	−0.0029 (6)	0.0019 (7)	0.0051 (7)
O8	0.0114 (7)	0.0125 (8)	0.0093 (8)	0.0046 (6)	0.0011 (6)	0.0038 (6)
O9	0.0083 (7)	0.0193 (9)	0.0080 (8)	0.0053 (6)	0.0011 (6)	0.0024 (7)
O10	0.0099 (7)	0.0060 (6)	0.0212 (10)	0.0017 (5)	0.0059 (7)	0.0020 (7)
O11	0.0060 (6)	0.0077 (6)	0.0146 (9)	−0.0005 (5)	0.0040 (6)	0.0009 (6)
O12	0.0191 (9)	0.0087 (7)	0.0069 (8)	−0.0009 (6)	−0.0009 (7)	0.0026 (6)

K—O4	2.789 (2)	P1—O7	1.480 (2)
K—O5	2.860 (2)	P1—O4vi	1.483 (2)
K—O6i	2.874 (2)	P1—O12	1.588 (2)
K—O2i	2.961 (2)	P1—O3iii	1.5968 (19)
K—O10ii	3.075 (3)	P1—Kvi	3.4868 (13)
K—O3iii	3.221 (2)	P2—O10iv	1.4795 (19)
K—O7ii	3.234 (3)	P2—O5	1.483 (2)
K—O11iv	3.326 (2)	P2—O11iv	1.6015 (18)
K—O7	3.370 (3)	P2—O3i	1.602 (2)
K—P3i	3.4008 (12)	P3—O6	1.482 (2)
K—P1ii	3.4868 (13)	P3—O2	1.4873 (19)
Eu—O9	2.3199 (19)	P3—O11	1.6005 (19)
Eu—O4	2.3775 (19)	P3—O1	1.6033 (19)
Eu—O10	2.3799 (18)	P3—Kvii	3.4008 (12)
Eu—O5	2.401 (2)	P4—O9	1.4784 (19)
Eu—O7	2.4045 (19)	P4—O8viii	1.484 (2)
Eu—O8	2.406 (2)	P4—O1	1.601 (2)
Eu—O6v	2.4214 (18)	P4—O12iv	1.601 (2)
Eu—O2	2.4827 (19)
O4—K—O5	59.57 (6)	O5—Eu—O2	141.68 (7)
O4—K—O6i	100.70 (7)	O7—Eu—O2	118.10 (7)
O5—K—O6i	89.02 (7)	O8—Eu—O2	72.99 (6)
O4—K—O2i	147.48 (7)	O6v—Eu—O2	77.51 (6)
O5—K—O2i	99.06 (6)	O7—P1—O4vi	118.08 (13)
O6i—K—O2i	51.47 (5)	O7—P1—O12	109.51 (12)
O4—K—O10ii	76.15 (6)	O4vi—P1—O12	110.78 (11)
O5—K—O10ii	118.26 (7)	O7—P1—O3iii	108.73 (11)
O6i—K—O10ii	143.04 (7)	O4vi—P1—O3iii	110.13 (12)
O2i—K—O10ii	135.75 (6)	O12—P1—O3iii	97.66 (11)
O4—K—O3iii	94.01 (6)	O10iv—P2—O5	121.60 (13)
O5—K—O3iii	93.77 (6)	O10iv—P2—O11iv	110.86 (11)
O6i—K—O3iii	164.29 (7)	O5—P2—O11iv	106.08 (11)
O2i—K—O3iii	112.83 (6)	O10iv—P2—O3i	107.58 (12)
O10ii—K—O3iii	46.46 (5)	O5—P2—O3i	109.67 (12)
O4—K—O7ii	49.24 (5)	O11iv—P2—O3i	98.65 (10)
O5—K—O7ii	108.54 (6)	O6—P3—O2	117.21 (12)
O6i—K—O7ii	97.63 (6)	O6—P3—O11	108.85 (11)
O2i—K—O7ii	138.36 (6)	O2—P3—O11	109.42 (10)
O10ii—K—O7ii	52.04 (5)	O6—P3—O1	106.70 (11)
O3iii—K—O7ii	96.13 (6)	O2—P3—O1	111.17 (11)
O4—K—O11iv	105.76 (6)	O11—P3—O1	102.44 (11)
O5—K—O11iv	46.23 (5)	O9—P4—O8viii	119.05 (12)
O6i—K—O11iv	78.27 (6)	O9—P4—O1	108.15 (11)
O2i—K—O11iv	57.13 (5)	O8viii—P4—O1	109.93 (11)
O10ii—K—O11iv	138.47 (6)	O9—P4—O12iv	108.86 (12)
O3iii—K—O11iv	92.53 (6)	O8viii—P4—O12iv	110.62 (12)
O7ii—K—O11iv	153.96 (6)	O1—P4—O12iv	98.17 (11)
O4—K—O7	55.48 (6)	P4—O1—P3	124.84 (11)
O5—K—O7	56.64 (6)	P3—O2—Eu	126.82 (12)
O6i—K—O7	144.25 (6)	P3—O2—Kvii	93.80 (9)
O2i—K—O7	135.83 (6)	Eu—O2—Kvii	139.28 (8)
O10ii—K—O7	63.35 (5)	P1ix—O3—P2vii	130.06 (14)
O3iii—K—O7	44.54 (5)	P1ix—O3—Kix	91.84 (9)
O7ii—K—O7	85.78 (3)	P2vii—O3—Kix	97.17 (9)
O11iv—K—O7	83.30 (6)	P1ii—O4—Eu	138.08 (12)
O9—Eu—O4	118.75 (7)	P1ii—O4—K	105.27 (10)
O9—Eu—O10	79.54 (7)	Eu—O4—K	108.28 (7)
O4—Eu—O10	142.30 (6)	P2—O5—Eu	143.49 (12)
O9—Eu—O5	71.81 (7)	P2—O5—K	110.57 (10)
O4—Eu—O5	71.94 (7)	Eu—O5—K	105.40 (8)
O10—Eu—O5	85.13 (7)	P3—O6—Eux	144.03 (13)
O9—Eu—O7	138.27 (7)	P3—O6—Kvii	97.49 (9)
O4—Eu—O7	75.03 (7)	Eux—O6—Kvii	118.48 (8)
O10—Eu—O7	70.79 (7)	P1—O7—Eu	148.46 (13)
O5—Eu—O7	76.95 (8)	P1—O7—Kvi	87.05 (10)
O9—Eu—O8	143.51 (7)	Eu—O7—Kvi	92.57 (7)
O4—Eu—O8	79.39 (7)	P1—O7—K	88.34 (10)
O10—Eu—O8	105.75 (7)	Eu—O7—K	91.59 (7)
O5—Eu—O8	143.72 (7)	Kvi—O7—K	175.37 (7)
O7—Eu—O8	74.50 (7)	P4xi—O8—Eu	130.26 (12)
O9—Eu—O6v	75.16 (7)	P4—O9—Eu	146.27 (13)
O4—Eu—O6v	75.02 (7)	P2iv—O10—Eu	138.15 (12)
O10—Eu—O6v	142.48 (6)	P2iv—O10—Kvi	106.53 (11)
O5—Eu—O6v	112.01 (7)	Eu—O10—Kvi	97.15 (7)
O7—Eu—O6v	143.80 (7)	P3—O11—P2iv	132.40 (12)
O8—Eu—O6v	80.43 (7)	P3—O11—Kiv	136.15 (9)
O9—Eu—O2	75.52 (7)	P2iv—O11—Kiv	88.55 (8)
O4—Eu—O2	143.69 (7)	P1—O12—P4iv	133.66 (14)
O10—Eu—O2	69.57 (7)

Table 1

Selected bond lengths (Å)

P1—O7	1.480 (2)
P1—O4i	1.483 (2)
P1—O12	1.588 (2)
P1—O3ii	1.5968 (19)
P2—O10iii	1.4795 (19)
P2—O5	1.483 (2)
P2—O11iii	1.6015 (18)
P2—O3iv	1.602 (2)
P3—O6	1.482 (2)
P3—O2	1.4873 (19)
P3—O11	1.6005 (19)
P3—O1	1.6033 (19)
P4—O9	1.4784 (19)
P4—O8v	1.484 (2)
P4—O1	1.601 (2)
P4—O12iii	1.601 (2)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) .