Dipotassium tris­­odium triphosphate, K₂Na₃P₃O₁₀

The structure of the title compound, K₂Na₃P₃O₁₀, is characterized by open chains of three PO₄ tetra­hedra linked by single oxygen bridges. The P₃O₁₀ groups have crystallographic twofold symmetry, with the central P atom being located on the twofold rotation axis. One of the sodium ions lies on a centre of inversion, whereas all the remaining atoms are in general positions. The structure is isotypic with that of the high-temperature form of Na₅P₃O₁₀ phase I.

Related literature

For compounds with related structures, see: Cruickshank (1964); Davies & Corbridge (1958); Dyroff (1965), Wiench et al. (1982); Dymon & King (1951); Corbridge (1960).

Experimental

Crystal data

• K₂Na₃P₃O₁₀

• M_r = 400.08

• Monoclinic, C 2/c

• a = 9.8866 (4) Å

• b = 5.6332 (2) Å

• c = 18.6577 (8) Å

• β = 96.199 (3)°

• V = 1033.03 (7) ų

• Z = 4

• Mo Kα radiation

• μ = 1.55 mm⁻¹

• T = 296 K

• 0.19 × 0.14 × 0.10 mm

Data collection

• Bruker APEXII CCD detector diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1999) T_min = 0.511, T_max = 0.638

• 12463 measured reflections

• 2830 independent reflections

• 2136 reflections with I > 2σ(I)

• R_int = 0.032

Refinement

• R[F² > 2σ(F²)] = 0.032

• wR(F²) = 0.080

• S = 1.08

• 2830 reflections

• 85 parameters

• Δρ_max = 0.63 e Å⁻³

• Δρ_min = −0.97 e Å⁻³

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia,1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: WinGX (Farrugia, 1999).

Supporting information

S1. Comment

The present triphosphate was obtained by chance, during the preparation of a mixed pyrophosphate. A bibliographic study of alkali triphosphates like M₅P₃0₁₀ shows that there are few known structures. Thus, in the case of sodium triphosphate, the crystal structures of two anhydrous forms noted Phase I and II were determined by Cruickshank (1964) and Davies & Corbridge (1958) and that of the hexahydrate was performed by Dyroff (1965) and re-examined by Wiench et al. (1982).

The structure of dipotassium trisodium triphosphate consists of open chains of three PO₄ tetrahedra linked by single oxygen bridges. The values of P–P (2.883 Å) distances and P—O—P (125.25°) angles are within the limits generally observed in condensed phosphate crystal chemistry. The internal symmetry of the P₃0₁₀ groups has a twofold symmetry, with the central phosphorus P2 atom being located on a binary axis. Moreover, the Na2 sodium ion lies on the symmetry center whereas all the remaining atoms are in general positions of the C2/c space group. The Na2 sodium atom located at Wyckoff position 4c (1/4, 3/4, 1/2) could be surrounded by a roughly octahedral arrangement of six oxygen atoms and the other sodium and potassium (Na1, K1) atoms are coordinated to six and eight oxygen atoms respectively. The Na2O₆ octahedra, Na1O₆ and K1O₈ polyhedra are connected through the apices to triphosphate groups and form a three-dimensional host lattice (Fig.1). The resulting 3-D framework presents intersecting tunnels running along the [010] and [110] directions, where the six-coordinated Na1⁺ cations are located (Fig.2). The structure of this compound is isotype to that of the high-temperature form of Na₅P₃0₁₀ phase I (Dymon and King, 1951 and Corbridge, 1960).

Related literature

For compounds with related structures, see: Cruickshank (1964); Davies & Corbridge (1958); Dyroff (1965), Wiench et al. (1982); Dymon & King (1951); Corbridge (1960).

S2. Experimental

The present triphosphate is obtained by chance, during the preparation of a mixture of pyrophosphate. Indeed, the powder phase NaKNiP₂O₇ synthesized by wet process is introduced into a platinum crucible, and then gradually heated to a temperature above its melting point (1173 K) for 2 h, followed by slow cooling of the order of 6 K per hour up to 673 K. Then the furnace is shuts down and the cooling is continued until room temperature. Small colourless single crystals of K₂Na₃P₃O₁₀ were isolated from the mixtures of phases.

S3. Refinement

The highest peak and the deepest hole in the final Fourier map are at 0.63 Å and 0.58 Å, respectively, from K1.

Computing details

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia,1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

Fig. 1. Plot of K2Na3P3O10 crystal structure showing polyhedra linkage. Displacement ellipsoids are drawn at the 50% probability level. Symmetry codes:(i) -x + 1/2, -y + 1/2, -z + 1; (ii) -x, -y, -z + 1; (iii) -x, -y + 1, -z + 1; (iv) x, y + 1, z; (v) -x, y, -z + 1/2; (vi) x - 1/2, y + 1/2, z; (vii) -x + 1/2, y + 1/2, -z + 1/2; (viii) x + 1/2, y - 1/2, z; (ix) x, y - 1, z; (x) -x + 1/2, -y - 1/2, -z + 1.

Fig. 2. Projection view of the K2Na3P3O10 framework structure showing tunnel running along b direction where the Na1 atoms are located.

Dipotassium trisodium triphosphate

Crystal data

K2Na3P3O10	F(000) = 784
Mr = 400.08	Dx = 2.572 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -c 2yc	Cell parameters from 2830 reflections
a = 9.8866 (4) Å	θ = 4.2–38.3°
b = 5.6332 (2) Å	µ = 1.55 mm^−1
c = 18.6577 (8) Å	T = 296 K
β = 96.199 (3)°	Block, colourless
V = 1033.03 (7) Å^3	0.19 × 0.14 × 0.10 mm
Z = 4

Data collection

Bruker APEXII CCD detector diffractometer	2830 independent reflections
Radiation source: fine-focus sealed tube	2136 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.032
ω and ϕ scans	θmax = 38.3°, θmin = 4.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1999)	h = −17→17
Tmin = 0.511, Tmax = 0.638	k = −8→9
12463 measured reflections	l = −32→32

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)] = 0.032	w = 1/[σ^2(Fo^2) + (0.0334P)^2 + 0.7541P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.080	(Δ/σ)max = 0.001
S = 1.08	Δρmax = 0.63 e Å^−3
2830 reflections	Δρmin = −0.97 e Å^−3
85 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0011 (3)

Special details

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
K1	0.09445 (3)	0.27218 (6)	0.57736 (2)	0.02014 (8)
P1	0.06781 (3)	0.22944 (6)	0.398705 (18)	0.00976 (7)
P2	0.0000	0.09573 (9)	0.2500	0.01288 (10)
Na1	0.21820 (7)	−0.30829 (11)	0.32759 (3)	0.01917 (13)
Na2	0.2500	−0.2500	0.5000	0.01344 (15)
O1	−0.07276 (11)	0.22433 (19)	0.42318 (6)	0.0184 (2)
O2	0.15106 (10)	0.44080 (18)	0.42676 (5)	0.01569 (19)
O3	0.14234 (10)	−0.00428 (18)	0.40638 (6)	0.01571 (19)
O4	0.04508 (11)	0.28577 (18)	0.31142 (5)	0.01663 (19)
O5	−0.12023 (12)	−0.0419 (2)	0.26927 (6)	0.0231 (2)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
K1	0.01413 (13)	0.01460 (13)	0.03200 (18)	0.00043 (10)	0.00389 (11)	0.00128 (11)
P1	0.00897 (13)	0.00981 (14)	0.01046 (14)	0.00010 (10)	0.00091 (10)	−0.00060 (10)
P2	0.0142 (2)	0.0135 (2)	0.0108 (2)	0.000	0.00129 (15)	0.000
Na1	0.0199 (3)	0.0173 (3)	0.0212 (3)	0.0060 (2)	0.0062 (2)	0.0047 (2)
Na2	0.0132 (3)	0.0131 (4)	0.0139 (3)	−0.0003 (3)	0.0008 (3)	−0.0006 (3)
O1	0.0136 (4)	0.0187 (5)	0.0244 (5)	−0.0006 (4)	0.0090 (4)	−0.0020 (4)
O2	0.0151 (4)	0.0140 (4)	0.0174 (4)	−0.0028 (3)	−0.0007 (3)	−0.0041 (3)
O3	0.0162 (4)	0.0126 (4)	0.0180 (4)	0.0044 (3)	0.0003 (3)	0.0015 (3)
O4	0.0239 (5)	0.0159 (4)	0.0095 (4)	−0.0021 (4)	−0.0010 (3)	0.0012 (3)
O5	0.0238 (5)	0.0246 (5)	0.0216 (5)	−0.0107 (4)	0.0056 (4)	0.0005 (4)

Geometric parameters (Å, º)

K1—O2^i	2.7960 (11)	P2—O4	1.5961 (11)
K1—O1^ii	2.8051 (11)	P2—O4^iv	1.5961 (11)
K1—O3^ii	2.8291 (11)	Na1—O5^v	2.4172 (14)
K1—O1^iii	2.8443 (11)	Na1—O3	2.4278 (12)
K1—O3^i	2.8987 (11)	Na1—O5^iv	2.4655 (13)
K1—O2^iii	2.9106 (11)	Na1—O2^vi	2.4753 (12)
K1—O2	3.0740 (11)	Na1—O1^v	2.5864 (13)
K1—O5^ii	3.1272 (12)	Na1—O4^vi	2.8527 (13)
P1—O3	1.5080 (10)	Na2—O2^vi	2.3599 (10)
P1—O2	1.5086 (10)	Na2—O2^i	2.3599 (10)
P1—O1	1.5092 (11)	Na2—O1^ii	2.3850 (10)
P1—O4	1.6506 (10)	Na2—O1^v	2.3850 (10)
P2—O5	1.4951 (11)	Na2—O3	2.3871 (10)
P2—O5^iv	1.4951 (11)	Na2—O3^vii	2.3871 (10)
O2^i—K1—O1^ii	68.95 (3)	O3—P1—O4	105.94 (6)
O2^i—K1—O3^ii	122.11 (3)	O2—P1—O4	101.64 (6)
O1^ii—K1—O3^ii	53.46 (3)	O1—P1—O4	105.69 (6)
O2^i—K1—O1^iii	119.70 (3)	O5—P2—O5^iv	117.54 (10)
O1^ii—K1—O1^iii	171.32 (4)	O5—P2—O4	110.04 (6)
O3^ii—K1—O1^iii	117.99 (3)	O5^iv—P2—O4	110.66 (6)
O2^i—K1—O3^i	52.85 (3)	O5—P2—O4^iv	110.66 (6)
O1^ii—K1—O3^i	121.17 (3)	O5^iv—P2—O4^iv	110.04 (6)
O3^ii—K1—O3^i	166.73 (4)	O4—P2—O4^iv	95.75 (8)
O1^iii—K1—O3^i	67.49 (3)	O5^v—Na1—O3	156.77 (5)
O2^i—K1—O2^iii	171.11 (4)	O5^v—Na1—O5^iv	103.17 (3)
O1^ii—K1—O2^iii	119.38 (3)	O3—Na1—O5^iv	83.79 (4)
O3^ii—K1—O2^iii	66.53 (3)	O5^v—Na1—O2^vi	105.62 (4)
O1^iii—K1—O2^iii	51.95 (3)	O3—Na1—O2^vi	79.92 (4)
O3^i—K1—O2^iii	119.27 (3)	O5^iv—Na1—O2^vi	141.23 (5)
O2^i—K1—O2	81.62 (3)	O5^v—Na1—O1^v	80.29 (4)
O1^ii—K1—O2	109.04 (3)	O3—Na1—O1^v	78.96 (4)
O3^ii—K1—O2	119.82 (3)	O5^iv—Na1—O1^v	133.13 (5)
O1^iii—K1—O2	73.13 (3)	O2^vi—Na1—O1^v	77.52 (4)
O3^i—K1—O2	72.92 (3)	O5^v—Na1—O4^vi	86.22 (4)
O2^iii—K1—O2	92.17 (3)	O3—Na1—O4^vi	114.11 (4)
O2^i—K1—O5^ii	82.10 (3)	O5^iv—Na1—O4^vi	103.10 (4)
O1^ii—K1—O5^ii	65.69 (3)	O2^vi—Na1—O4^vi	54.20 (3)
O3^ii—K1—O5^ii	70.56 (3)	O1^v—Na1—O4^vi	123.75 (4)
O1^iii—K1—O5^ii	114.55 (3)	O2^vi—Na2—O2^i	180.0
O3^i—K1—O5^ii	96.19 (3)	O2^vi—Na2—O1^ii	96.16 (4)
O2^iii—K1—O5^ii	103.88 (3)	O2^i—Na2—O1^ii	83.85 (4)
O2—K1—O5^ii	163.68 (3)	O2^vi—Na2—O1^v	83.85 (4)
O2^i—K1—O1	108.73 (3)	O2^i—Na2—O1^v	96.15 (4)
O1^ii—K1—O1	83.10 (3)	O1^ii—Na2—O1^v	180.000 (1)
O3^ii—K1—O1	72.27 (3)	O2^vi—Na2—O3	83.11 (3)
O1^iii—K1—O1	92.86 (3)	O2^i—Na2—O3	96.89 (3)
O3^i—K1—O1	120.50 (3)	O1^ii—Na2—O3	96.09 (4)
O2^iii—K1—O1	70.83 (3)	O1^v—Na2—O3	83.91 (4)
O2—K1—O1	47.59 (3)	O2^vi—Na2—O3^vii	96.89 (3)
O5^ii—K1—O1	141.07 (3)	O2^i—Na2—O3^vii	83.11 (3)
O3—P1—O2	114.42 (6)	O1^ii—Na2—O3^vii	83.91 (4)
O3—P1—O1	114.27 (6)	O1^v—Na2—O3^vii	96.09 (4)
O2—P1—O1	113.31 (6)	O3—Na2—O3^vii	180.00 (4)

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