Powder diffraction study of Ba(NH₄)₄(PO₃)₆

The crystal structure of barium tetra­ammonium poly{hexa­kis[phosphate(V)]} was solved by direct methods from laboratory X-ray powder diffraction data collected at room temperature. The trigonal crystal structure is isostructural with BaCs₄(PO₃)₆. The Ba²⁺ cation and one of the N atoms lie on a threefold axis, whereas all remaining non-H atoms are in general positions. The Ba²⁺ cation is bonded to nine O atoms from three polyphosphate chains to form a distorted tricapped trigonal prism as coordination polyhedron. Links between the polyphosphate chains and the Ba²⁺ ions result in a three-dimensional network, with tunnels and cavities filled by ammonium cations.

Key indicators

• Powder X-ray study
• T = 295 K
• Mean [sigma](P-O) = 0.016 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

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

   2 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
   0 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 (Rodrigues-Carvajal, 2001); data reduction: local program; program(s) used to solve structure: EXPO (Altomare et al., 1999); 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).

Babarium tetraammonium poly{hexakis[phosphate(V)]}

Crystal data

Ba(NH4)4(PO3)6	F(000) = 668.0
Mr = 683.32	Dx = 2.340 Mg m^−3
Trigonal, P31c	Cu Kα radiation, λ = 1.5418 Å
Hall symbol: P 3 -2c	T = 295 K
a = 11.1936 (2) Å	Particle morphology: needle-like
c = 8.9393 (3) Å	colourless
V = 970.00 (4) Å^3	flat_sheet, 30 × 30 mm
Z = 2	Specimen preparation: Prepared at 295 K

Data collection

Carl Zeiss (Jena) HZG-4A diffractometer	Data collection mode: reflection
Radiation source: fine-focus sealed X-ray tube, BSV-29	Scan method: step
Ni filtered monochromator	2θmin = 8°, 2θmax = 105°, 2θstep = 0.02°
Specimen mounting: packed powder pellet

Refinement

Refinement on Inet	49 parameters
Least-squares matrix: full with fixed elements per cycle	10 restraints
Rp = 0.066	H-atom parameters constrained
Rwp = 0.089	Weighting scheme based on measured s.u.'s
Rexp = 0.156	(Δ/σ)max = 0.001
RBragg = 0.045	Background function: polynomial, with six refined coefficients
4851 data points	Preferred orientation correction: Marsh–Dollase function (Marsh, 1932; Dollase, 1986); correction for the [001] preferred orientation of needle-like grains; refined parameters G1 = 1.39(2), G2 = 0.09(4).
Profile function: pseudo-Voight; the refined value of the η parameter is 0.692(13).

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
Ba	0.66667	0.33333	0.25000	0.0126 (18)*
P1	0.4440 (8)	0.4557 (8)	0.4793 (7)	0.0090 (11)*
P2	0.2948 (6)	0.2758 (5)	0.2286 (6)	0.0090 (11)*
O1	0.441 (4)	0.574 (3)	0.535 (5)	0.014 (2)*
O2	0.583 (2)	0.459 (3)	0.482 (5)	0.014 (2)*
O3	0.3681 (17)	0.4137 (13)	0.3229 (16)	0.014 (2)*
O4	0.1441 (14)	0.2042 (16)	0.265 (5)	0.014 (2)*
O5	0.3715 (12)	0.2049 (15)	0.274 (4)	0.014 (2)*
O6	0.3159 (18)	0.322 (2)	0.0563 (14)	0.014 (2)*
N1	0.66666	0.33333	0.73064	0.014 (2)*
H1	0.66667	0.33333	0.63564	0.05000*
H2	0.60310	0.34800	0.76228	0.05000*
N2	0.008 (6)	0.232 (3)	0.518 (7)	0.014 (2)*
H3	0.03929	0.20510	0.44645	0.05000*
H4	0.07096	0.30981	0.54750	0.05000*
H5	−0.06149	0.23692	0.48787	0.05000*
H6	−0.01805	0.17354	0.58921	0.05000*

Geometric parameters (Å, º)

Ba—O1^i	2.73 (5)	P2—O3	1.581 (14)
Ba—O1^ii	2.73 (5)	P2—O4	1.50 (2)
Ba—O1^iii	2.73 (5)	P2—O5	1.488 (19)
Ba—O2	2.91 (2)	P2—O6	1.604 (14)
Ba—O2^iv	2.91 (2)	N1—H1	0.8500
Ba—O2^v	2.91 (2)	N1—H2	0.8500
Ba—O5	2.877 (17)	N1—H2^iv	0.8500
Ba—O5^iv	2.877 (17)	N1—H2^v	0.8500
Ba—O5^v	2.877 (17)	N2—H3	0.8500
P1—O1	1.43 (4)	N2—H4	0.8400
P1—O2	1.54 (3)	N2—H5	0.8500
P1—O3	1.581 (17)	N2—H6	0.8500
P1—O6^vi	1.628 (19)
O1—P1—O2	118 (2)	P1^i—O6—P2	127.0 (12)
O1—P1—O3	109 (2)	H1—N1—H2	109.00
O1—P1—O6^vi	110.2 (19)	H1—N1—H2^iv	109.00
O2—P1—O3	114.1 (18)	H1—N1—H2^v	109.00
O2—P1—O6^vi	111.6 (16)	H2—N1—H2^iv	110.00
O3—P1—O6^vi	91.2 (9)	H2—N1—H2^v	110.00
O3—P2—O4	107.6 (14)	H2^iv—N1—H2^v	110.00
O3—P2—O5	102.7 (12)	H3—N2—H4	109.00
O3—P2—O6	106.0 (9)	H3—N2—H5	110.00
O4—P2—O5	116.8 (12)	H3—N2—H6	109.00
O4—P2—O6	109.0 (18)	H4—N2—H5	111.00
O5—P2—O6	113.8 (16)	H4—N2—H6	110.00
P1—O3—P2	134.5 (11)	H5—N2—H6	108.00
O1—P1—O3—P2	−157 (2)	O4—P2—O3—P1	94 (2)
O2—P1—O3—P2	69 (2)	O5—P2—O3—P1	−30 (2)
O6^vi—P1—O3—P2	−45 (2)	O6—P2—O3—P1	−149.3 (18)
O1—P1—O6^vi—P2^vi	−42 (3)	O3—P2—O6—P1^i	42 (2)
O2—P1—O6^vi—P2^vi	91 (2)	O4—P2—O6—P1^i	157.5 (16)
O3—P1—O6^vi—P2^vi	−152.3 (18)	O5—P2—O6—P1^i	−70.2 (18)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2	0.85	2.4600	3.02 (4)	124.0
N1—H1···O2^iv	0.85	2.4600	3.02 (4)	124.0
N1—H1···O2^v	0.85	2.4600	3.02 (4)	124.0
N1—H2···O3^vi	0.85	2.3100	3.155 (17)	172.0
N2—H3···O4	0.85	2.0000	2.83 (7)	162.0
N2—H4···O1^vii	0.84	2.5200	3.20 (5)	139.0
N2—H4···O5^vi	0.84	2.4100	3.02 (7)	130.0
N2—H5···O5^viii	0.85	2.3600	3.04 (7)	136.0
N2—H5···O2^vii	0.85	2.4400	3.10 (7)	135.0
N2—H6···O4^ix	0.85	2.0700	2.86 (7)	155.0

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