Crystal structure of dimanganese(II) zinc bis-[ortho-phosphate(V)] monohydrate.

The title compound, Mn2Zn(PO4)2·H2O, was obtained under hydro-thermal conditions. The structure is isotypic with other transition metal phosphates of the type M 3- xM' x (PO4)2·H2O, but shows no statistical disorder of the three metallic sites. The principal building units are distorted [MnO6] and [MnO5(H2O)] octa-hedra, a distorted [ZnO5] square pyramid and two regular PO4 tetra-hedra. The connection of the polyhedra leads to a framework structure. Two types of layers parallel to (-101) can be distinguished in this framework. One layer contains [Zn2O8] dimers linked to PO4 tetra-hedra via common edges. The other layer is more corrugated and contains [Mn2O8(H2O)2] dimers and [MnO6] octa-hedra linked together by common edges. The PO4 tetra-hedra link the two types of layers into a framework structure with channels parallel to [101]. The H atoms of the water mol-ecules point into the channels and form O-H⋯O hydrogen bonds (one of which is bifurcated) with framework O atoms across the channels.

Chemical context

The great structural diversity of metal-based phosphates, associated with their physical properties makes this family of compounds inter­esting as potential functional materials, e.g. as catalysts (Viter & Nagornyi, 2009 ▸; Weng et al., 2009 ▸) or ion-exchangers (Jignasa et al., 2006 ▸). Among the wide variety of metal phosphates, one of our inter­ests is focused on mixed metallic orthophosphates of general formula M 3− (PO4)2·H2O. The present communication reports the hydro­thermal synthesis and structural characterization of a new member of this family, Mn2Zn(PO4)2·H2O.

Structural commentary

The structure of the title compound is built up from four different types of building units: [MnO6] and [MnO5(H2O)] octa­hedra, [ZnO5] square pyramids and PO4 tetra­hedra, as shown in Fig. 1 ▸. Whereas the [MnO6] octa­hedron is more or less regular with Mn—O distances in the range 2.1254 (13) to 2.2590 (13) Å, the [MnO5(H2O)] octa­hedron is significantly distorted with five equal Mn—O distances in the range 2.1191 (13) to 2.1556 (16) and one considerably longer Mn—O distance to the water ligand of 2.5163 (15) Å; the ZnO5 square pyramid is also distorted with four shorter Zn—O distances between 1.9546 (13) and 2.0347 (12) Å and one longer Zn—O distance, likewise to the water O atom [2.3093 (14) Å]; the two PO4 tetra­hedra are rather regular [P—O distances between 1.5322 (13) and 1.5570 (13) Å; O—P—O angles between 102.92 (7) and 111.62 (8)°]. These polyhedra are arranged in such a way as to build up two types of layers parallel to (01). One layer contains two [ZnO5] polyhedra linked together by edge-sharing into a [Zn2O8] dimer that in turn is linked to PO4 tetra­hedra. The other layer contains dimers of the type [Mn2O8(H2O)2] (also formed by edge-sharing of two [MnO5(H2O)] octa­hedra), connecting [MnO6] octa­hedra and PO4 tetra­hedra through common vertices. The two types of layers are linked by common edges and vertices into a framework structure with channels parallel to [101]. The water mol­ecules of the [MnO5(H2O)] octa­hedra protrude into these channels and develop hydrogen bonds (one bifurcated) of medium-to-weak strength to framework O atoms across the channels (Fig. 2 ▸; Table 1 ▸).

Figure 1

The principal building units in the structure of Mn2Zn(PO4)2·H2O. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen bonds are indicated by dashed lines. [Symmetry codes: (i) −x + 1, −y + 1, −z + 1; (ii) x + , −y + , z + ; (iii) −x + 2, −y + 1, −z + 1; (iv) −x + , y + , −z + ; (v) −x + , y − , −z + ; (vi) x − , −y + , z − ; (vii) x − , −y + , z − ; (viii) −x + , y + , −z + .]

Figure 2

Polyhedral representation of Mn2Zn(PO4)2·H2O showing channels extending parallel to [101]. Hydrogen bonds are shown as dashed lines.

Table 1

Hydrogen-bond geometry (, )

DHA	DH	HA	D A	DHA
O9H1O7	0.89	1.97	2.7866(19)	151
O9H2O5i	0.91	2.16	2.8687(19)	134
O9H2O1ii	0.91	2.48	3.0494(19)	120

Symmetry codes: (i) ; (ii) .

The title compound adopts the Fe3(PO4)2·H2O structure type (Moore & Araki, 1975 ▸) and is isotypic with various structures of general formula M 3− (PO4)2·H2O: CuMn2(PO4)2·H2O (Liao et al., 1995 ▸); Co2.59Zn0.41(PO4)2·H2O (Sørensen et al., 2005 ▸); Co2.39Cu0.61(PO4)2·H2O (Assani et al., 2010 ▸); Mg1.65Cu1.35(PO4)2·H2O (Khmiyas et al. 2015 ▸).

Synthesis and crystallization

Crystals of Mn2Zn(PO4)2·H2O were obtained by hydro­thermal treatment of zinc oxide (0.0406 g), metallic manganese (0.0824 g), phospho­ric acid (0.1 ml) and 12.5 ml of distilled water, in a proportion corresponding to the molar ratio Zn: Mn: P = 1: 3: 3. The hydro­thermal reaction was conducted in a 23 ml Teflon-lined autoclave under autogenous pressure at 493 K for five days. After being filtered, washed with deionized water and dried in air, the reaction product consisted of two types of crystals, the first as off-white parallelepipeds corresponding to Mn7(PO4)2(HPO4)4 (Riou et al., 1987 ▸) and the second as colourless parallelepipeds corres­ponding to the title compound.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. The O-bound H atoms were initially located in a difference map. In the last refinement cycle the distances were fixed at 0.89 and 0.91 Å, respectively, and the H atoms refined in the riding-model approximation with U iso(H) set to 1.5U eq(O). The highest peak and the deepest hole in the final Fourier map are at 0.32 Å and 0.30 Å, respectively, from Mn1 and Zn1.

Table 2

Experimental details

Crystal data
Chemical formula	Mn2Zn(PO4)2H2O
M r	383.21
Crystal system, space group	Monoclinic, P21/n
Temperature (K)	296
a, b, c ()	8.1784(2), 10.1741(2), 9.0896(2)
()	114.142(1)
V (3)	690.17(3)
Z	4
Radiation type	Mo K
(mm1)	7.54
Crystal size (mm)	0.32 0.27 0.19
Data collection
Diffractometer	Bruker X8 APEX
Absorption correction	Multi-scan (SADABS; Bruker, 2009 ▸)
T min, T max	0.574, 0.748
No. of measured, independent and observed [I > 2(I)] reflections	11327, 2407, 2305
R int	0.023
(sin /)max (1)	0.746
Refinement
R[F 2 > 2(F 2)], wR(F 2), S	0.019, 0.052, 1.11
No. of reflections	2407
No. of parameters	127
H-atom treatment	H-atom parameters constrained
max, min (e 3)	0.94, 0.84

Computer programs: APEX2 and SAINT (Bruker, 2009 ▸), SHELXS97 and SHELXL97 (Sheldrick, 2008 ▸), ORTEP-3 for Windows (Farrugia, 2012 ▸), DIAMOND (Brandenburg, 2006 ▸) and publCIF (Westrip, 2010 ▸).

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989015000341/wm5102sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015000341/wm5102Isup2.hkl

CCDC reference: 1042563

Additional supporting information: crystallographic information; 3D view; checkCIF report

Mn2Zn(PO4)2·H2O	F(000) = 736
Mr = 383.21	Dx = 3.688 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 2407 reflections
a = 8.1784 (2) Å	θ = 2.8–32.0°
b = 10.1741 (2) Å	µ = 7.54 mm−1
c = 9.0896 (2) Å	T = 296 K
β = 114.142 (1)°	Parallelepiped, off-white
V = 690.17 (3) Å3	0.32 × 0.27 × 0.19 mm
Z = 4

Bruker X8 APEX diffractometer	2407 independent reflections
Radiation source: fine-focus sealed tube	2305 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
φ and ω scans	θmax = 32.0°, θmin = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −12→12
Tmin = 0.574, Tmax = 0.748	k = −14→15
11327 measured reflections	l = −13→13

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.019	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.052	H-atom parameters constrained
S = 1.11	w = 1/[σ2(Fo2) + (0.0248P)2 + 1.0141P] where P = (Fo2 + 2Fc2)/3
2407 reflections	(Δ/σ)max = 0.001
127 parameters	Δρmax = 0.94 e Å−3
0 restraints	Δρmin = −0.84 e Å−3

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 > 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.

	x	y	z	Uiso*/Ueq
Mn1	0.88638 (3)	0.35884 (3)	0.46580 (3)	0.00768 (6)
Mn2	0.48057 (3)	0.38305 (3)	0.21880 (3)	0.00726 (6)
Zn1	0.12609 (3)	0.62028 (2)	0.06179 (2)	0.00934 (6)
P1	0.70438 (5)	0.08456 (4)	0.32706 (5)	0.00553 (8)
P2	0.38560 (5)	0.67442 (4)	0.36388 (5)	0.00613 (8)
O1	0.58212 (17)	0.03301 (13)	0.40831 (15)	0.0102 (2)
O2	0.87050 (16)	0.15076 (13)	0.45546 (15)	0.0094 (2)
O3	0.59293 (17)	0.18429 (12)	0.19887 (15)	0.0092 (2)
O4	0.76145 (17)	−0.03217 (12)	0.25178 (15)	0.0092 (2)
O5	0.23736 (18)	0.77279 (13)	0.26723 (16)	0.0123 (2)
O6	0.36400 (17)	0.63194 (13)	0.51688 (15)	0.0104 (2)
O7	0.57269 (16)	0.73311 (13)	0.41028 (15)	0.0110 (2)
O8	0.35411 (17)	0.55914 (13)	0.24330 (15)	0.0107 (2)
O9	0.88135 (18)	0.58568 (14)	0.57419 (16)	0.0130 (2)
H1	0.7876	0.6203	0.4923	0.019*
H2	0.8793	0.5969	0.6731	0.019*

	U11	U22	U33	U12	U13	U23
Mn1	0.00519 (11)	0.00776 (11)	0.00860 (11)	−0.00070 (8)	0.00129 (8)	0.00274 (8)
Mn2	0.00657 (11)	0.00704 (11)	0.00777 (11)	−0.00016 (8)	0.00254 (9)	−0.00025 (8)
Zn1	0.00839 (10)	0.00949 (10)	0.00884 (9)	0.00028 (6)	0.00219 (7)	0.00093 (6)
P1	0.00538 (16)	0.00594 (17)	0.00519 (16)	0.00046 (13)	0.00209 (13)	−0.00030 (13)
P2	0.00556 (16)	0.00676 (17)	0.00569 (16)	0.00008 (13)	0.00193 (13)	−0.00044 (13)
O1	0.0107 (5)	0.0111 (5)	0.0126 (5)	0.0015 (4)	0.0087 (5)	0.0025 (4)
O2	0.0079 (5)	0.0105 (5)	0.0073 (5)	−0.0020 (4)	0.0008 (4)	−0.0025 (4)
O3	0.0099 (5)	0.0080 (5)	0.0081 (5)	0.0022 (4)	0.0020 (4)	0.0013 (4)
O4	0.0083 (5)	0.0091 (5)	0.0099 (5)	0.0017 (4)	0.0033 (4)	−0.0027 (4)
O5	0.0121 (5)	0.0135 (6)	0.0108 (5)	0.0070 (5)	0.0041 (4)	0.0035 (4)
O6	0.0106 (5)	0.0137 (6)	0.0071 (5)	−0.0006 (4)	0.0038 (4)	0.0016 (4)
O7	0.0081 (5)	0.0129 (6)	0.0120 (5)	−0.0031 (4)	0.0041 (4)	−0.0030 (4)
O8	0.0107 (5)	0.0093 (5)	0.0099 (5)	0.0011 (4)	0.0021 (4)	−0.0035 (4)
O9	0.0109 (5)	0.0181 (6)	0.0106 (5)	0.0020 (5)	0.0051 (4)	0.0007 (5)

Mn1—O6i	2.1191 (13)	Zn1—O1vi	2.0242 (13)
Mn1—O2	2.1208 (14)	Zn1—O1viii	2.0347 (12)
Mn1—O3ii	2.1464 (12)	Zn1—O5	2.3093 (14)
Mn1—O9iii	2.1504 (14)	P1—O3	1.5327 (13)
Mn1—O4iv	2.1556 (13)	P1—O4	1.5355 (13)
Mn1—O9	2.5163 (15)	P1—O2	1.5377 (13)
Mn2—O8	2.1254 (13)	P1—O1	1.5570 (13)
Mn2—O5v	2.1533 (13)	P2—O7	1.5322 (13)
Mn2—O4iv	2.1921 (13)	P2—O6	1.5340 (13)
Mn2—O2vi	2.2126 (13)	P2—O5	1.5401 (13)
Mn2—O6i	2.2166 (13)	P2—O8	1.5532 (13)
Mn2—O3	2.2590 (13)	O9—H1	0.8939
Zn1—O7vii	1.9546 (13)	O9—H2	0.9131
Zn1—O8	2.0174 (13)
O6i—Mn1—O2	90.23 (5)	O4iv—Mn2—O3	87.66 (5)
O6i—Mn1—O3ii	109.27 (5)	O2vi—Mn2—O3	76.87 (5)
O2—Mn1—O3ii	81.31 (5)	O6i—Mn2—O3	87.34 (5)
O6i—Mn1—O9iii	161.48 (5)	O7vii—Zn1—O8	132.60 (5)
O2—Mn1—O9iii	107.27 (5)	O7vii—Zn1—O1vi	100.19 (6)
O3ii—Mn1—O9iii	80.06 (5)	O8—Zn1—O1vi	99.81 (5)
O6i—Mn1—O4iv	81.32 (5)	O7vii—Zn1—O1viii	117.98 (5)
O2—Mn1—O4iv	118.14 (5)	O8—Zn1—O1viii	107.48 (5)
O3ii—Mn1—O4iv	158.49 (5)	O1vi—Zn1—O1viii	80.41 (5)
O9iii—Mn1—O4iv	84.99 (5)	O7vii—Zn1—O5	87.57 (5)
O6i—Mn1—O9	76.07 (5)	O8—Zn1—O5	67.61 (5)
O2—Mn1—O9	157.28 (5)	O1vi—Zn1—O5	167.20 (5)
O3ii—Mn1—O9	86.18 (5)	O1viii—Zn1—O5	105.05 (5)
O9iii—Mn1—O9	89.00 (5)	O3—P1—O4	111.58 (7)
O4iv—Mn1—O9	78.15 (5)	O3—P1—O2	110.68 (7)
O8—Mn2—O5v	89.03 (5)	O4—P1—O2	109.99 (7)
O8—Mn2—O4iv	98.10 (5)	O3—P1—O1	106.62 (7)
O5v—Mn2—O4iv	167.53 (5)	O4—P1—O1	108.79 (7)
O8—Mn2—O2vi	104.14 (5)	O2—P1—O1	109.08 (7)
O5v—Mn2—O2vi	90.14 (5)	O7—P2—O6	109.42 (7)
O4iv—Mn2—O2vi	97.96 (5)	O7—P2—O5	111.62 (8)
O8—Mn2—O6i	91.85 (5)	O6—P2—O5	110.15 (7)
O5v—Mn2—O6i	91.25 (5)	O7—P2—O8	110.32 (7)
O4iv—Mn2—O6i	78.36 (5)	O6—P2—O8	112.31 (8)
O2vi—Mn2—O6i	163.97 (5)	O5—P2—O8	102.92 (7)
O8—Mn2—O3	173.90 (5)	H1—O9—H2	114.6
O5v—Mn2—O3	84.95 (5)

D—H···A	D—H	H···A	D···A	D—H···A
O9—H1···O7	0.89	1.97	2.7866 (19)	151
O9—H2···O5ix	0.91	2.16	2.8687 (19)	134
O9—H2···O1ii	0.91	2.48	3.0494 (19)	120