Buy article online - an online subscription or single-article purchase is required to access this article.
Download citation
Download citation
link to html
In a new polymorph of hexa­aqua­magnesium(II) bis­(hypophosphite), [Mg(H2O)6](H2PO2)2, the planes of trans water mol­ecules forming the octahedral coordination sphere of the Mg atoms are in a staggered conformation. The magnesium(II) cations are in a pseudo-face-centered cubic arrangement, with a \simeq 10.294 Å and tetrahedral cavities are occupied by P atoms. Hypophosphite anions are hydrogen bonded to the coordinated water mol­ecules.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680300758X/mg6022sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S160053680300758X/mg6022Isup2.hkl
Contains datablock I

Key indicators

  • Single-crystal X-ray study
  • T = 295 K
  • Mean [sigma](P-O) = 0.002 Å
  • R factor = 0.021
  • wR factor = 0.048
  • Data-to-parameter ratio = 12.9

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
GOODF_01 Alert C The least squares goodness of fit parameter lies outside the range 0.80 <> 2.00 Goodness of fit given = 0.739 PLAT_420 Alert C D-H Without Acceptor P(1) - H(1) ?
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
2 Alert Level C = Please check

Comment top

Studies of hexaaquametal(II) bis(hypophosphites) have been reported earlier (Ferrari & Colla, 1937; Pédrazuela et al., 1953; Galigné & Dumas, 1973; Kuratieva et al., 2002, 2003). The structure of a new polymorph, (I), of [Mg(H2O)6](H2PO2)2 is described here; this is different from that previously reported (Galigné & Dumas, 1973) but similar to that of [Mg(H2O)6](ClO2)2 (Marsh, 1991), excluding the H atoms present in the hypophosphite anion. The packing of the MgII cations, P and O atoms of hypophosphite anions is the same as in the structure of [Ni(H2O)6](H2PO2)2 and Cl and O atoms in [Mg(H2O)6](ClO2)2. The magnesium cations are in a pseudo-face-centered cubic arrangement, with a 10.294 Å (10.371 Å in [Mg(H2O)6](ClO2)2) and tetrahedral cavities occupied by P atoms.

The first coordination sphere of the MgII cation consists of six water molecules forming a slightly distorted octahedron and appearing in only one type of orientation. Planes of trans-coordinated water molecules are in a staggered conformation, as in [Ni(H2O)6](H2PO2)2 (Kuratieva et al., 2003) and [Mg(H2O)6](ClO2)2 (Marsh, 1991), but different from [Mg(H2O)6](H2PO2)2 (Galigné & Dumas, 1973), [Co(H2O)6](H2PO2)2, and [Co0.5Ni0.5(H2O)6](H2PO2)2 (Kuratieva et al., 2002), in which a pair of trans water molecules is in eclipsed conformation. The six coordinated water molecules occur in two groups. The two molecules corresponding to the O1w atoms [Mg—O 2.042 (3) Å] have their planes perpendicular to the basal plane formed by the four other molecules and the MgII cation. The angle between the normal to the planes of these water molecules is 90.0° {as in [Mg(H2O)6](ClO2)2}. The four molecules corresponding to the O2w atoms (Mg—O 2.060 (2) Å) have their planes perpendicular to the basal plane; the angle between the normal to the planes of trans coordinated molecules of this type is 83.3 (2)° {88.3 (3)° in [Mg(H2O)6](ClO2)2)}.

The second coordination sphere of the MgII cation consists of eight hypophosphite anions, which are hydrogen bonded to water molecules. Although the packing of MgII cations and P atoms is similar, the orientation of hypophosphite anions differs from that in [Mg(H2O)6](H2PO2)2 (Galigné & Dumas, 1973), [Co(H2O)6](H2PO2)2, and [Co0.5Ni0.5(H2O)6](H2PO2)2 (Kuratieva et al., 2002), and resembles that in [Ni(H2O)6](H2PO2)2 (Kuratieva et al., 2003) and [Mg(H2O)6](ClO2)2 (Marsh, 1991). The geometry of the hypophosphite anion remains practically the same as in previous structures (Naumov et al., 2001, 2002; Kuratieva et al., 2002, 2003) (Table 1). Each O atom of the hypophosphite anion is hydrogen bonded to three water molecules from different complex cations (Table 2; thick dashed lines in Fig. 2). Each H atom is surrounded by three water molecules from other complex cations; these H atoms are situated directly above the centers of the triangles formed by the O atoms of these three water molecules (thin dashed lines in Fig. 2). The average P—H···O contact is 2.87 (2) Å. The environment of the hypophosphite anion is similar to that found in the other hexaaquametal(II) bis(hypophosphites) listed above.

Experimental top

[Mg(H2O)6](H2PO2)2 was synthesized by slow evaporation of an aqueous solution of magnesium(II) hypophosphite, prepared by adding a solution of calcium(II) hypophosphite, Ca(H2PO2)2, to a solution of magnesium(II) sulfate heptahydrate, MgSO4·7H2O. The reaction mixture was stored at room temperature for one week in air.

Refinement top

The H atoms were located from a difference electron-density map and refined without constraints.

Computing details top

Data collection: CD4CA0 (Enraf-Nonius, 1989); cell refinement: CD4CA0 (Enraf-Nonius, 1989); data reduction: CD4CA0 (Enraf-Nonius, 1989); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures top
[Figure 1] Fig. 1. The environment of hexaaquamagnesium(II) cation in relation to the hypophosphite anions. Displacement ellipsoids are plotted at the 50% probability level and H atoms are drawn as small spheres of arbitrary radii [symmetry codes: (i) y − 1/2, 1 − x, 1/2 − z; (ii) 1/2 − x, 3/2 − y, z; (iii) 1 − y, 1/2 + x, 1/2 − z; (iv) 1/2 − y, x, z − 1/2].
[Figure 2] Fig. 2. The environment of the hypophosphite anion of [Mg(H2O)6](H2PO2)2 in relation to the hexaaquamagnesium(II) cations, viewed along [110]. Thick dashed lines indicate the O—H···O—P hydrogen bonds and thin dashed lines indicate the Ow···H—P contacts. Displacement ellipsoids are plotted at the 50% probability level and H atoms are drawn as small spheres of arbitrary radii.
hexaaquamagnesium(II) bis(hypophosphite) top
Crystal data top
H12MgO6·2(H2O2P)Dx = 1.598 Mg m3
Mr = 262.38Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P42/nmcCell parameters from 22 reflections
Hall symbol: -P 4ac 2aθ = 11.7–14.9°
a = 7.2187 (9) ŵ = 0.48 mm1
c = 10.4639 (13) ÅT = 295 K
V = 545.27 (12) Å3Prism, colorless
Z = 20.24 × 0.20 × 0.16 mm
F(000) = 276
Data collection top
Enraf-Nonius CAD4
diffractometer
238 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.038
Graphite monochromatorθmax = 29.1°, θmin = 3.4°
2θ/θ scansh = 09
Absorption correction: empirical (using intensity measurements)
CADDAT (Enraf-Nonius, 1989)
k = 09
Tmin = 0.904, Tmax = 0.925l = 014
809 measured reflections3 standard reflections every 60 min
427 independent reflections intensity decay: none
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.021All H-atom parameters refined
wR(F2) = 0.048 w = 1/[σ2(Fo2) + (0.0118P)2]
where P = (Fo2 + 2Fc2)/3
S = 0.74(Δ/σ)max < 0.001
427 reflectionsΔρmax = 0.18 e Å3
33 parametersΔρmin = 0.20 e Å3
0 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.016 (2)
Crystal data top
H12MgO6·2(H2O2P)Z = 2
Mr = 262.38Mo Kα radiation
Tetragonal, P42/nmcµ = 0.48 mm1
a = 7.2187 (9) ÅT = 295 K
c = 10.4639 (13) Å0.24 × 0.20 × 0.16 mm
V = 545.27 (12) Å3
Data collection top
Enraf-Nonius CAD4
diffractometer
238 reflections with I > 2σ(I)
Absorption correction: empirical (using intensity measurements)
CADDAT (Enraf-Nonius, 1989)
Rint = 0.038
Tmin = 0.904, Tmax = 0.9253 standard reflections every 60 min
809 measured reflections intensity decay: none
427 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0210 restraints
wR(F2) = 0.048All H-atom parameters refined
S = 0.74Δρmax = 0.18 e Å3
427 reflectionsΔρmin = 0.20 e Å3
33 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Mg10.25000.75000.25000.0319 (4)
P10.25000.25000.50851 (9)0.0335 (3)
H10.101 (3)0.25000.4297 (17)0.012 (5)*
O10.25000.4273 (2)0.58483 (15)0.0368 (5)
O1W0.25000.75000.0549 (3)0.0496 (8)
H1W0.342 (4)0.75000.011 (2)0.076 (13)*
O2W0.04819 (19)0.54819 (19)0.25000.0474 (5)
H2W0.048 (3)0.465 (2)0.2047 (14)0.045 (6)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mg10.0335 (6)0.0335 (6)0.0285 (8)0.0000.0000.000
P10.0428 (8)0.0298 (7)0.0280 (5)0.0000.0000.000
O10.0442 (11)0.0312 (11)0.0351 (9)0.0000.0000.0021 (9)
O1W0.0288 (18)0.090 (3)0.0302 (14)0.0000.0000.000
O2W0.0464 (8)0.0464 (8)0.0496 (12)0.0126 (10)0.0179 (9)0.0179 (9)
Geometric parameters (Å, º) top
Mg1—O1Wi2.042 (3)P1—H1iv1.36 (2)
Mg1—O1W2.042 (3)P1—O11.5088 (18)
Mg1—O2W2.060 (2)P1—O1iv1.5088 (18)
Mg1—O2Wii2.060 (2)P1—H11.356 (19)
Mg1—O2Wiii2.060 (2)O1W—H1W0.81 (2)
Mg1—O2Wi2.060 (2)O2W—H2W0.762 (14)
O1Wi—Mg1—O1W180.0O2W—Mg1—O2Wi90.0
O1Wi—Mg1—O2W90.0O2Wii—Mg1—O2Wi90.0
O1W—Mg1—O2W90.0O2Wiii—Mg1—O2Wi180.0
O1Wi—Mg1—O2Wii90.0H1iv—P1—O1108.8 (3)
O1W—Mg1—O2Wii90.0H1iv—P1—O1iv108.8 (3)
O2W—Mg1—O2Wii180.0O1—P1—O1iv116.08 (14)
O1Wi—Mg1—O2Wiii90.0H1iv—P1—H1105.2 (15)
O1W—Mg1—O2Wiii90.0O1—P1—H1108.8 (3)
O2W—Mg1—O2Wiii90.0O1iv—P1—H1108.8 (3)
O2Wii—Mg1—O2Wiii90.0Mg1—O1W—H1W124 (2)
O1Wi—Mg1—O2Wi90.0Mg1—O2W—H2W123.7 (15)
O1W—Mg1—O2Wi90.0
Symmetry codes: (i) y1/2, x+1, z+1/2; (ii) x+1/2, y+3/2, z; (iii) y+1, x+1/2, z+1/2; (iv) x+1/2, y+1/2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H1W···O1iii0.81 (2)1.94 (2)2.750 (2)177 (3)
O2W—H2W···O1v0.762 (14)2.006 (14)2.7662 (14)175 (2)
Symmetry codes: (iii) y+1, x+1/2, z+1/2; (v) y+1/2, x, z1/2.

Experimental details

Crystal data
Chemical formulaH12MgO6·2(H2O2P)
Mr262.38
Crystal system, space groupTetragonal, P42/nmc
Temperature (K)295
a, c (Å)7.2187 (9), 10.4639 (13)
V3)545.27 (12)
Z2
Radiation typeMo Kα
µ (mm1)0.48
Crystal size (mm)0.24 × 0.20 × 0.16
Data collection
DiffractometerEnraf-Nonius CAD4
diffractometer
Absorption correctionEmpirical (using intensity measurements)
CADDAT (Enraf-Nonius, 1989)
Tmin, Tmax0.904, 0.925
No. of measured, independent and
observed [I > 2σ(I)] reflections
809, 427, 238
Rint0.038
(sin θ/λ)max1)0.684
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.021, 0.048, 0.74
No. of reflections427
No. of parameters33
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.18, 0.20

Computer programs: CD4CA0 (Enraf-Nonius, 1989), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEPIII (Burnett & Johnson, 1996).

Selected geometric parameters (Å, º) top
Mg1—O1W2.042 (3)P1—O11.5088 (18)
Mg1—O2W2.060 (2)P1—H11.356 (19)
O1Wi—Mg1—O1W180.0O2W—Mg1—O2Wi90.0
O1W—Mg1—O2W90.0O1—P1—O1iii116.08 (14)
O2W—Mg1—O2Wii180.0H1iii—P1—H1105.2 (15)
Symmetry codes: (i) y1/2, x+1, z+1/2; (ii) x+1/2, y+3/2, z; (iii) x+1/2, y+1/2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H1W···O1iv0.81 (2)1.94 (2)2.750 (2)177 (3)
O2W—H2W···O1v0.762 (14)2.006 (14)2.7662 (14)175 (2)
Symmetry codes: (iv) y+1, x+1/2, z+1/2; (v) y+1/2, x, z1/2.
 

Subscribe to Acta Crystallographica Section E: Crystallographic Communications

The full text of this article is available to subscribers to the journal.

If you have already registered and are using a computer listed in your registration details, please email support@iucr.org for assistance.

Buy online

You may purchase this article in PDF and/or HTML formats. For purchasers in the European Community who do not have a VAT number, VAT will be added at the local rate. Payments to the IUCr are handled by WorldPay, who will accept payment by credit card in several currencies. To purchase the article, please complete the form below (fields marked * are required), and then click on `Continue'.
E-mail address* 
Repeat e-mail address* 
(for error checking) 

Format*   PDF (US $40)
   HTML (US $40)
   PDF+HTML (US $50)
In order for VAT to be shown for your country javascript needs to be enabled.

VAT number 
(non-UK EC countries only) 
Country* 
 

Terms and conditions of use
Contact us

Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds