(NH₄)[B₃PO₆(OH)₃]·0.5H₂O

The title compound, ammonium catena-[monoboro-monodihydrogendiborate-monohydrogenphosphate] hemihydrate, was obtained under solvothermal conditions using glycol as the solvent. The crystal structure is constructed of one-dimensional infinite borophosphate chains, which are inter­connected by ammonium ions and water mol­ecules via a complex hydrogen-bond network to form a three-dimensional structure. The water mol­ecules of crystallization are disordered over inversion centres, and their H atoms were not located.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](O-B) = 0.002 Å
• H-atom completeness 88%
• R factor = 0.038
• wR factor = 0.099
• Data-to-parameter ratio = 12.7

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT306_ALERT_2_A Isolated Oxygen Atom (H-atoms Missing ?) .......         OW

Author Response: Since O10 is located in the equivalent positions, it is difficult to fix the hydrogen positions for O10 by the difference Fourier maps. Thererfore, it have to be omitted.

Alert level C
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT045_ALERT_1_C Calculated and Reported Z Differ by ............       0.50 Ratio
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.94
PLAT430_ALERT_2_C Short Inter D...A Contact  OW     ..  O5      ..       2.87 Ang.
PLAT430_ALERT_2_C Short Inter D...A Contact  OW     ..  O5      ..       2.87 Ang.
PLAT716_ALERT_1_C H...A   Unknown or Inconsistent Label ..........          .
PLAT716_ALERT_1_C H...A   Unknown or Inconsistent Label ..........          .
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........          1

Alert level G
FORMU01_ALERT_1_G  There is a discrepancy between the atom counts in the
            _chemical_formula_sum and _chemical_formula_moiety. This is
            usually due to the moiety formula being in the wrong format.
            Atom count from _chemical_formula_sum:   H8 B3 N1 O9.5 P1
            Atom count from _chemical_formula_moiety:H12 B3 N2 O9.5 P1
FORMU01_ALERT_2_G  There is a discrepancy between the atom counts in the
            _chemical_formula_sum and the formula from the _atom_site* data.
            Atom count from _chemical_formula_sum:H8 B3 N1 O9.5 P1
            Atom count from the _atom_site data:  H7 B3 N1 O9.5 P1
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.939
            Tmax scaled      0.932 Tmin scaled      0.833
CELLZ01_ALERT_1_G Difference between formula and atom_site contents detected.
CELLZ01_ALERT_1_G WARNING: H atoms missing from atom site list. Is this intentional?
           From the CIF: _cell_formula_units_Z    2
           From the CIF: _chemical_formula_sum  B3 H8 N1 O9.5 P1
           TEST: Compare cell contents of formula and atom_site data

           atom    Z*formula  cif sites diff
           B          6.00      6.00    0.00
           H         16.00     14.00    2.00
           N          2.00      2.00    0.00
           O         19.00     19.00    0.00
           P          2.00      2.00    0.00
PLAT793_ALERT_1_G Check the Absolute Configuration of P1     = ...          R

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

   9 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   4 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
   0 ALERT type 5 Informative message, check

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S1. Comment

In the asymmetic unit of the title compound three crystallographically distinct boron atoms are present. Two of them are coordinated by three O-atoms to form nearly triagonal planar BO₃ units, which are interconnected with one BO₄ tetrahedron to form a 6-membered borate ring. The slightly distorted PO₄ tetrahedron bridges the borate rings by sharing common vertices with the BO₄ groups, leading to an infinite borophosphate chain (Fig.1) extending parallel to the a axis (Fig. 2). According to the latest review on the crystal chemistry of borophosphates (Ewald et al., 2007), the functional building units (FBU) are of the type 2Δ2&square;:<2Δ&square;>&square;, forming cB zweier-single chains.

A complex hydrogen-bond network (Fig. 2) consolidates the borophosphate chains into a three-dimensional structure. The OH groups of parallel chains interact with the intermediate NH₄ cations via N—H···O hydrogen bonds and with terminal framework O atoms via O—H···O hydrogen bonds. The latter type of hydrogen bonds is also observed for the water molecules which are located on inversion centres.

In comparison to (NH₄)[B₃PO₆(OH)₃]^.0.5H₂O, the structures of the related compounds Li[B₃PO₆(OH)₃] (Hauf & Kniep, 1997) and (NH₄)₂[B₃PO₇(OH)₂] (Hauf & Kniep, 1996) comprise similar borophosphate chains. However, Li[B₃PO₆(OH)₃] comprises cB single-chains with a different periodicity in which the rings alternate with P^2/4 units, and (NH₄)₂[B₃PO₇(OH)₂] is made up of borophosphae chains where the PO₃OH group is replaced by PO₄, resulting in a different stacking of the chains and thus a different hydrogen bonding scheme.

Related literature

The related compounds Li[B₃PO₆(OH)₃] (Hauf & Kniep, 1997) and (NH₄)₂[B₃PO₇(OH)₂] (Hauf & Kniep, 1996) comprise similar borophosphate chains, but show a different periodicity of the rings and a replacement of PO₃OH by PO₄ for the latter. A review on the crystal chemical classification of borophosphates was published recently (Ewald et al., 2007).

S2. Experimental

The title compound was prepared under solvothermal conditons. 1.04 g of (NH₄)₂B₄O₇ (SCR, >99.5%), 0.9 g NH₄H₂PO₄ (SCR, >99.5%) and 5 ml of glycol (SCR, >99%) were placed in a Teflon-lined stainless steel autoclave and heated to 403 K for 5 d, followed by cooling to room temperature. Colourless rod-shaped crystals were obtained.

S3. Refinement

H atoms bonded to N and to framework-O atoms were located in a difference map and were refined with N—H = 0.90–0.94 and O—H = 0.79–0.82 Å. The O atom (Ow) of the water molecule is situated on an inversion centre. It was not possible to locate the corresponding H atoms, which points to a disorder due to the formation of various hydrogen bonds.

Computing details

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. View of a part of the infinite borophospate chains, with atom labels and 50% probability displacement ellipsoids. H atoms are displayed as spheres of arbitrary radius. [Symmetry code: (i) -x, -y, -z.]
	Fig. 2. The packing of the title compound, as viewed down the a axis, showing the hydrogen bonding scheme (dashed lines). Colour code: B yellow; P pink; O red; N blue; H white.

ammonium catena-[monoboro-mono-dihydrogendiborate-monohydrogenphosphate] hemihydrate

Crystal data

(NH4)[B3PO6(OH)3]·0.5H2O	Z = 2
Mr = 237.48	F(000) = 240
Triclinic, P1	Dx = 1.808 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.3665 (2) Å	Cell parameters from 2516 reflections
b = 9.3680 (4) Å	θ = 5–55°
c = 10.8267 (8) Å	µ = 0.35 mm^−1
α = 81.532 (9)°	T = 296 K
β = 85.369 (9)°	Rod, colourless
γ = 83.641 (8)°	0.35 × 0.20 × 0.20 mm
V = 434.41 (4) Å^3

Data collection

Bruker SMART CCD diffractometer	1996 independent reflections
Radiation source: fine-focus sealed tube	1788 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.024
ω scans	θmax = 27.5°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −5→5
Tmin = 0.887, Tmax = 0.993	k = −12→12
6501 measured reflections	l = −14→13

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)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.099	All H-atom parameters refined
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0522P)^2 + 0.3672P] where P = (Fo^2 + 2Fc^2)/3
1996 reflections	(Δ/σ)max = 0.001
157 parameters	Δρmax = 0.41 e Å^−3
0 restraints	Δρmin = −0.48 e Å^−3

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

	x	y	z	Uiso*/Ueq
P1	0.38071 (10)	0.32784 (5)	0.87493 (4)	0.01661 (15)
B1	−0.0816 (4)	0.2710 (2)	0.73583 (18)	0.0161 (4)
B2	1.2037 (5)	0.2978 (2)	0.52774 (19)	0.0215 (4)
B3	0.2114 (5)	0.0630 (2)	0.6493 (2)	0.0223 (4)
O1	0.5814 (3)	0.29141 (15)	0.75672 (12)	0.0209 (3)
O2	0.4119 (3)	0.48339 (14)	0.89765 (12)	0.0231 (3)
O3	0.0456 (3)	0.33077 (15)	0.83671 (12)	0.0229 (3)
O4	0.4403 (3)	0.21875 (15)	0.98843 (13)	0.0263 (3)
O5	0.0212 (3)	0.11655 (13)	0.73935 (12)	0.0213 (3)
O6	1.0000 (3)	0.35280 (13)	0.61382 (12)	0.0202 (3)
O7	0.6934 (4)	0.62278 (16)	0.57923 (14)	0.0333 (4)
O8	0.6974 (4)	0.08201 (16)	1.33756 (16)	0.0391 (4)
O9	0.3100 (3)	0.15115 (14)	0.54252 (12)	0.0255 (3)
N1	−0.0636 (5)	0.6964 (2)	0.8055 (2)	0.0339 (4)
Ow	0.0000	0.0000	1.0000	0.0738 (10)
H1	−0.195 (7)	0.730 (3)	0.866 (3)	0.044 (8)*
H2	0.768 (8)	0.539 (4)	0.580 (3)	0.060 (10)*
H3	0.073 (8)	0.620 (4)	0.842 (3)	0.055 (9)*
H4	0.603 (8)	0.104 (4)	1.399 (3)	0.055 (9)*
H5	0.026 (8)	0.774 (4)	0.762 (3)	0.058 (9)*
H6	−0.167 (9)	0.665 (4)	0.745 (4)	0.070 (11)*
H7	0.4445 (1)	0.4834 (1)	0.9712 (1)	0.048 (1)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
P1	0.0144 (2)	0.0187 (2)	0.0176 (2)	−0.00196 (16)	0.00014 (17)	−0.00570 (17)
B1	0.0148 (8)	0.0170 (9)	0.0166 (9)	−0.0014 (7)	0.0017 (7)	−0.0044 (7)
B2	0.0244 (10)	0.0182 (9)	0.0200 (10)	0.0017 (8)	0.0036 (8)	−0.0024 (7)
B3	0.0268 (10)	0.0168 (9)	0.0218 (10)	−0.0010 (8)	0.0045 (8)	−0.0021 (8)
O1	0.0134 (6)	0.0309 (7)	0.0207 (6)	−0.0026 (5)	0.0003 (5)	−0.0117 (5)
O2	0.0285 (7)	0.0187 (6)	0.0242 (7)	−0.0022 (5)	−0.0054 (5)	−0.0083 (5)
O3	0.0131 (6)	0.0341 (7)	0.0244 (7)	−0.0020 (5)	0.0004 (5)	−0.0151 (6)
O4	0.0267 (7)	0.0255 (7)	0.0247 (7)	−0.0015 (5)	−0.0008 (6)	0.0014 (5)
O5	0.0254 (7)	0.0164 (6)	0.0203 (6)	−0.0004 (5)	0.0068 (5)	−0.0021 (5)
O6	0.0238 (6)	0.0157 (6)	0.0190 (6)	0.0021 (5)	0.0039 (5)	−0.0012 (5)
O7	0.0507 (10)	0.0181 (7)	0.0247 (7)	0.0054 (6)	0.0147 (7)	0.0020 (6)
O8	0.0572 (11)	0.0165 (7)	0.0360 (9)	0.0054 (7)	0.0233 (8)	0.0003 (6)
O9	0.0356 (8)	0.0159 (6)	0.0216 (7)	0.0024 (5)	0.0110 (6)	−0.0019 (5)
N1	0.0409 (11)	0.0272 (9)	0.0313 (10)	−0.0006 (8)	0.0034 (9)	−0.0018 (8)
Ow	0.104 (3)	0.061 (2)	0.0554 (19)	−0.0294 (19)	−0.0163 (19)	0.0156 (15)

Geometric parameters (Å, º)

P1—O4	1.4984 (14)	B3—O9	1.386 (3)
P1—O2	1.5354 (13)	O1—B1^iii	1.466 (2)
P1—O3	1.5487 (13)	O2—H7	0.8202 (13)
P1—O1	1.5503 (13)	O6—B1^iii	1.465 (2)
B1—O5	1.462 (2)	O7—B2^ii	1.354 (3)
B1—O6^i	1.465 (2)	O7—H2	0.81 (4)
B1—O1^i	1.466 (2)	O8—B3^iv	1.363 (2)
B1—O3	1.470 (2)	O8—H4	0.79 (4)
B2—O6	1.353 (2)	O9—B2^i	1.391 (2)
B2—O7^ii	1.354 (3)	N1—H1	0.90 (3)
B2—O9^iii	1.391 (2)	N1—H3	0.94 (3)
B3—O5	1.347 (2)	N1—H5	0.92 (4)
B3—O8^iv	1.363 (2)	N1—H6	0.92 (4)
O4—P1—O2	112.48 (8)	O5—B3—O9	121.62 (17)
O4—P1—O3	111.15 (8)	O8^iv—B3—O9	119.41 (17)
O2—P1—O3	105.07 (8)	B1^iii—O1—P1	129.61 (11)
O4—P1—O1	113.18 (8)	P1—O2—H7	109.52 (12)
O2—P1—O1	110.67 (8)	B1—O3—P1	131.73 (11)
O3—P1—O1	103.64 (7)	B3—O5—B1	123.09 (15)
O5—B1—O6^i	111.34 (14)	B2—O6—B1^iii	123.07 (14)
O5—B1—O1^i	109.82 (14)	B2^ii—O7—H2	109 (2)
O6^i—B1—O1^i	107.39 (14)	B3^iv—O8—H4	111 (2)
O5—B1—O3	110.95 (14)	B3—O9—B2^i	118.75 (15)
O6^i—B1—O3	110.65 (14)	H1—N1—H3	109 (3)
O1^i—B1—O3	106.51 (13)	H1—N1—H5	108 (3)
O6—B2—O7^ii	123.54 (17)	H3—N1—H5	116 (3)
O6—B2—O9^iii	120.76 (17)	H1—N1—H6	112 (3)
O7^ii—B2—O9^iii	115.63 (16)	H3—N1—H6	110 (3)
O5—B3—O8^iv	118.96 (18)	H5—N1—H6	103 (3)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O4^v	0.90 (3)	1.93 (3)	2.821 (3)	172 (3)
N1—H3···O2	0.94 (3)	1.92 (4)	2.849 (3)	169 (3)
N1—H5···O8^vi	0.92 (4)	2.04 (4)	2.942 (3)	168 (3)
N1—H6···O7^i	0.92 (4)	2.05 (4)	2.946 (3)	164 (3)
O7—H2···O6	0.81 (4)	1.92 (4)	2.7170 (19)	166 (3)
O8—H4···O9^vii	0.79 (4)	2.00 (4)	2.789 (2)	171 (3)
O2—H7···O2^vi	0.8201 (13)	1.6804 (13)	2.476 (2)	163.02 (5)
Ow···O5			2.869 (3)
Ow···O4			2.944 (2)

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