Ammonium scandium tetra­fluoride

Stephens, N.F.; Lightfoot, P.

doi:10.1107/S0108270106044520

inorganic compounds

STRUCTURAL
CHEMISTRY

ISSN: 2053-2296

Volume 62| Part 12| December 2006| Pages i103-i105

doi:10.1107/S0108270106044520

Ammonium scandium tetrafluoride

Nicholas F. Stephens ^a and Philip Lightfoot ^a ^*

^aSchool of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland
^*Correspondence e-mail: pl@st-and.ac.uk

(Received 27 September 2006; accepted 24 October 2006; online 22 November 2006)

The title compound, NH₄ScF₄, is an addition to the AMF₄ family of layered perovskite-like structures. The structure consists of a two-dimensional array of corner-sharing ScF₆ octahedra, which produces anionic sheets of stoichiometry [ScF₄]⁻ stacked along the c axis. The layers are separated by charge-balancing ammonium cations, which hydrogen bond to the apical F atoms of adjacent layers. This structure may be viewed as a `single-layer' fluoride analogue of the Dion–Jacobson family of oxides.

Comment

The title compound, NH₄ScF₄, (I), was produced during our exploratory studies in the hydrothermal chemistry of organically templated scandium fluorides (Stephens et al., 2004 ; Stephens & Lightfoot, 2006 ). This compound arises from an in situ breakdown of the organic template (see Experimental). It is related to several other layered fluorides of stoichiometry AMF₄ and may also be regarded as an n = 1 Dion–Jacobson phase (Dion et al., 1981 ).

The asymmetric unit (Fig. 1) contains one unique Sc site on a general position, having quite regular octahedral symmetry (Table 1). There are five crystallographically independent F sites and two N sites, both on mirror planes.

Fig. 2 shows that (I) is built from puckered layers of vertex-sharing octahedra, typical of layered perovskites. The layers are eclipsed relative to each other with respect to the a axis, but staggered by b/4 along b. Extensive hydrogen bonding occurs between adjacent layers, mediated by the ammonium cations (Table 2). The only N—H⋯F hydrogen bonds are those between ammonium cations and the `apical' F atoms that project into the interlayer space. This hydrogen bonding fulfills bond-valence requirements around the apical F atoms F2 and F3, as shown in Table 3.

Both the raw diffraction data and the derived model display a significant degree of pseudosymmetry (e.g. the bond lengths involving F1/F4 and F2/F3). An alternative model in space group Amma, with b′ = b/2, was also considered. However, our refinements confirm that the chosen model is correct; refinements in the higher-symmetry model lead to anomalously elongated ellipsoids for the `in-plane' F atoms, transverse to the Sc—F—Sc linkages. In fact, the pseudosymmetry is due to `octahedral tilting', and the difference between the two models is clarified in Fig. 3. In addition to the tilting relative to the b axis, shown in Fig. 2(b), there is a second tilt mode around the c axis, which is allowed in the correct Pmcn model but forbidden in the approximate Amma model. The two models are analogous to those in KFeF₄ (Lapasset et al., 1986 ), which undergoes a structural phase transition from KFeF₄(III) to KFeF₄(II) at 368 K, corresponding to Pmcn to Amma. We have not explored the possibility of such a phase transition in the present case.

In comparison with other compositionally related AMF₄ compounds, (I) is isotypic with KGaF₄ (Courbion et al., 1989 ). Interestingly, however, more precisely similar compositions have different structure types; for example, NH₄FeF₄ (Leblanc et al., 1985 ) has the same type of layer as (I), but the [ScF₄]⁻ sheets are eclipsed along both a and b, whereas KScF₄, has a unique `corrugated sheet' structure containing both cis- and trans-vertex-sharing octahedra (Champarnaud-Mesjard & Frit, 1992 ).

Figure 1
The asymmetric unit of (I), with displacement ellipsoids drawn at the 50% probability level [symmetry code: (i) −x, y + $[{1\over 2}]$ , −z + $[{1\over 2}]$ ].

Figure 2
(a) A projection along [100], showing staggered octahedra. (b) A projection along [010], showing eclipsed octahedra.

Figure 3
A view of a single layer along [001], showing (a) the Pmcn model with the additional c axis tilt mode and (b) the Amma model, with b′ = b/2.

Experimental

Scandium oxide (0.138 g), water (5 ml) and a 40% aqueous solution of HF (0.5 ml) were heated in a Teflon-lined steel autoclave for 1 h at 463 K. To this, ethylene glycol (5 ml) and 1,3-diaminopropane (0.4 ml) were added, and the resulting mixture was heated at the same temperature for four days. The product was filtered off, washed with water and allowed to dry at room temperature overnight. Powder X-ray diffraction revealed predominantly (I) as the product, together with a small amount of ScF₃. Compound (I) was heated to 1073 K at a rate of 5 K min⁻¹ under N₂ gas. Thermogravimmetric analysis shows a single-step weight loss of 19.6% from 573 to 698 K (20% calculated). Powder X-ray diffraction of the residue shows that this decomposition product is ScF₃.

Crystal data

NH₄ScF₄
M_r = 139.00
Orthorhombic, P m c n
a = 7.862 (2) Å
b = 8.088 (2) Å
c = 13.503 (4) Å
V = 858.6 (4) Å³
Z = 8
D_x = 2.151 Mg m⁻³
Mo Kα radiation
μ = 1.67 mm⁻¹
T = 93 (2) K
Prism, colourless
0.10 × 0.03 × 0.02 mm

Data collection

Rigaku/MSC CCD area-detector diffractometer
ω scans
Absorption correction: multi-scan (SADABS; Bruker, 1999 ) T_min = 0.825, T_max = 0.970
5191 measured reflections
847 independent reflections
587 reflections with I > 2σ(I)
R_int = 0.026
θ_max = 25.3°

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.028
wR(F²) = 0.102
S = 1.11
847 reflections
75 parameters
Only H-atom coordinates refined
w = 1/[σ²(F_o²) + (0.0519P)² + 0.1485P] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max = 0.005
Δρ_max = 0.40 e Å⁻³
Δρ_min = −0.40 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

Sc—F2	1.9904 (12)
Sc—F3	1.9919 (12)
Sc—F1	2.0272 (7)
Sc—F4	2.0273 (7)
Sc—F5ⁱ	2.0320 (19)
Sc—F5	2.0325 (19)

F2—Sc—F3	179.61 (9)
F1—Sc—F4	179.82 (7)
F5ⁱ—Sc—F5	179.713 (18)
Scⁱⁱ—F1—Sc	151.46 (10)
Scⁱⁱⁱ—F4—Sc	151.82 (10)
Sc^iv—F5—Sc	168.48 (8)
Symmetry codes: (i) $[-x, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (ii) $[-x-{\script{1\over 2}}, y, z]$ ; (iii) $[-x+{\script{1\over 2}}, y, z]$ ; (iv) -x, $[y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯F2	0.91 (3)	1.97 (3)	2.836 (2)	159 (2)
N1—H2⋯F3^v	0.97 (4)	2.11 (3)	2.858 (3)	132.0 (9)
N1—H3⋯F2^vi	0.86 (4)	2.21 (3)	2.853 (3)	131.3 (14)
N2—H4⋯F3^vii	0.84 (4)	2.24 (3)	2.867 (3)	132.1 (14)
N2—H5⋯F3	0.93 (3)	1.95 (3)	2.837 (2)	158 (2)
N2—H6⋯F2^viii	0.99 (4)	2.11 (3)	2.872 (4)	132.1 (9)
Symmetry codes: (v) $[-x+{1\over2}, -y+{3\over2}, z-{1\over2}]$ ; (vi) $[x+{1\over2}, -y+2, -z]$ ; (vii) $[x-{1\over2}]$ , -y+2, -z+1; (viii) $[-x-{1\over2}, -y+{3\over2}, z+{1\over2}]$ .

Table 3
Bond valence parameters

Bond	s_ij	∑s_ij
Sc F2	0.54	–
Sc F3	0.53	–
Sc F1	0.49	–
Sc F4	0.49	–
Sc F5	0.48	–
Sc F5	0.48	–
	–	3.00
F1 Sc	0.49 × 2	0.97
F2 Sc	0.54	0.54
F3 Sc	0.53	0.53
F4 Sc	0.49 × 2	0.97
F5 Sc	0.48	–
F5 Sc	0.48	0.96
Note: s_ij values calculated for B = 0.37; Brese & O'Keeffe (1991 ) extrapolated.

Systematic absences were consistent with space groups Pmcn (62) or P2₁cn (33). Successful refinement of the structure in centrosymmetric Pmcn, together with the lack of any contradictory physical property measurements, meant that this was preferred over P2₁cn. Pmcn [a non-standard setting of Pnma (62)] was chosen as this defines the perovskite-like layers to lie perpendicular to c, which is the convention in perovskite chemistry. H atoms were located from a difference Fourier map and were refined freely; the U_iso(H) values were fixed at 0.018 Å².

Data collection: CrystalClear (Rigaku/MSC, 2005 ); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2001 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S0108270106044520/bc3020sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S0108270106044520/bc3020Isup2.hkl

Comment top

The title compound, NH₄ScF₄ (I) was produced during our exploratory studies in the hydrothermal chemistry of organically templated scandium fluorides (Stephens et al., 2004; Stephens & Lightfoot, 2006). This compound arises from an in situ breakdown of the organic template (see Experimental). It is related to several other layered fluorides of stoichiometry AMF₄ and may also be regarded as an n = 1 Dion–Jacobson phase (Dion et al., 1981).

The asymmetric unit (Fig. 1) contains of one unique Sc site on a general position, having quite regular octahedral symmetry (Table 1). There are five crytallographically independent F sites and two N sites, both on mirror planes.

Fig. 2 shows that (I) is built from puckered layers of vertex-sharing octahedra, typical of layered perovskites. The layers are eclipsed relative to each other with respect to the a axis, but staggered by b/4 along b. Extensive hydrogen bonding occurs between adjacent layers, mediated by the ammonium cations (Table 2). The only N—H···F hydrogen bonds are those between ammonium cations and the `apical' F atoms that project into the interlayer space. This hydrogen bonding fulfills bond valence requirements around the apical F atoms F2 and F3, as shown in Table 3.

Both the raw diffraction data and the derived model display a significant degree of pseudo-symmetry (e.g. bond lengths involving F1/F4 and F2/F3). An alternative model in space group Amma, with b' = b/2, was also considered. However, our refinements confirm that the chosen model is correct; refinements in the higher-symmetry model lead to anomalously elongated ellipsoids for the `in-plane' F atoms, transverse to the Sc—F—Sc linkages. In fact, the pseudo-symmetry is due to 'octahedral tilting', and the difference between the two models is clarified in Fig. 3. In addition to the tilting relative to the b axis, shown in Fig. 2(b), there is a second tilt mode around the c axis, which is allowed in the correct Pmcn model but forbidden in the approximate Amma model. The two models are analogous to those in KFeF₄ (Lapasset et al., 1986), which undergoes a structural phase transition from KFeF₄(III) to KFeF₄(II) at 368 K, corresponding to Pmcn to Amma. We have not explored the possibility of such a phase transition in the present case.

In comparison with other compositionally related AMF₄ compounds, (I) is isotypic with KGaF₄ (Courbion et al., 1989). Interestingly, however, more precisely similar compositions have different structure types; for example, NH₄FeF₄ (Leblanc et al., 1985) has the same type of layer as (I), but the [ScF₄]⁻ sheets are eclipsed along both a and b, whereas KScF₄, has a unique `corrugated sheet' structure containing both cis- and trans-vertex-sharing octahedra (Champarnaud-Mesjard & Frit, 1992).

Experimental top

Scandium oxide (0.138 g), water (5 ml) and 0.5 ml of a 40% aqueous solution of HF were heated in a Teflon-lined steel autoclave for 1 h at 463 K. To this, ethylene glycol (5 ml) and 1,3-diaminopropane (0.4 ml) was added and heated at the same temperature for four days. The product was filtered off, washed in water and allowed to dry at room temperature overnight. Powder X-ray diffraction revealed predominantly (I) as the product, together with a small amount of ScF₃. Compound (I) was heated to 1073 K at 5 K min⁻¹ under N₂ gas. Thermogravimmetric analysis shows a single-step weight loss of 19.6% from 573 to 698 K (20% calculated). Powder X-ray diffraction of the residue shows that this decomposition product is ScF₃.

Computing details top

Data collection: CrystalClear (Rigaku/MSC, 2005); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2001); software used to prepare material for publication: SHELXL97.

Figures top

	Fig. 1. The asymmetric unit of (I), with displacement ellipsoids drawn at the 50% probability level [symmetry codes: (i) −x, 1/2 + y, 1/2 − z].
	Fig. 2. (a) Projection along [100], showing staggered octahedra. (b) Projection along [010], showing eclipsed octahedra
	Fig. 3. Plan view of a single layer along [001]. (a) Pmcn model showing the additional c axis tilt mode. (b) Amma model, with b' = b/2.

Ammonium scandium tetrafluoride top

Crystal data top

NH₄ScF₄	D_x = 2.151 Mg m⁻³
M_r = 139.00	Melting point: not measured K
Orthorhombic, Pmcn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2a	Cell parameters from 120 reflections
a = 7.862 (2) Å	θ = 2.5–25.4°
b = 8.088 (2) Å	µ = 1.67 mm⁻¹
c = 13.503 (4) Å	T = 93 K
V = 858.6 (4) Å³	Prism, colorless
Z = 8	0.10 × 0.03 × 0.02 mm
F(000) = 544

Data collection top

Rigaku/MSC CCD area-detector diffractometer	847 independent reflections
Radiation source: rotating anode	587 reflections with I > 2σ(I)
Confocal monochromator	R_int = 0.026
Detector resolution: 14.6306 pixels mm^-1	θ_max = 25.3°, θ_min = 2.9°
ω scans	h = −9→8
Absorption correction: multi-scan (SADABS; Bruker, 1999)	k = −8→9
T_min = 0.825, T_max = 0.970	l = −16→16
5191 measured reflections

Refinement top

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)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.102	Only H-atom coordinates refined
S = 1.11	w = 1/[σ²(F_o²) + (0.0519P)² + 0.1485P] where P = (F_o² + 2F_c²)/3
847 reflections	(Δ/σ)_max = 0.005
75 parameters	Δρ_max = 0.40 e Å⁻³
0 restraints	Δρ_min = −0.40 e Å⁻³

Crystal data top

NH₄ScF₄	V = 858.6 (4) Å³
M_r = 139.00	Z = 8
Orthorhombic, Pmcn	Mo Kα radiation
a = 7.862 (2) Å	µ = 1.67 mm⁻¹
b = 8.088 (2) Å	T = 93 K
c = 13.503 (4) Å	0.10 × 0.03 × 0.02 mm

Data collection top

Rigaku/MSC CCD area-detector diffractometer	847 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 1999)	587 reflections with I > 2σ(I)
T_min = 0.825, T_max = 0.970	R_int = 0.026
5191 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.028	0 restraints
wR(F²) = 0.102	Only H-atom coordinates refined
S = 1.11	Δρ_max = 0.40 e Å⁻³
847 reflections	Δρ_min = −0.40 e Å⁻³
75 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

	x	y	z	U_iso*/U_eq
Sc1	−0.00011 (3)	0.87501 (8)	0.25037 (2)	0.0052 (3)
F1	−0.2500	0.9003 (2)	0.28413 (13)	0.0112 (5)
F2	−0.05123 (18)	0.87620 (18)	0.10600 (8)	0.0120 (3)
F3	0.05074 (18)	0.87219 (18)	0.39488 (8)	0.0120 (3)
F4	0.2500	0.8499 (2)	0.21704 (13)	0.0118 (5)
F5	−0.02582 (19)	0.6250 (2)	0.25142 (7)	0.0134 (4)
N1	0.2500	0.8765 (5)	−0.0095 (2)	0.0105 (6)
N2	−0.2500	0.8760 (5)	0.5110 (2)	0.0118 (6)
H1	0.163 (3)	0.851 (3)	0.0327 (19)	0.018*
H2	0.2500	0.779 (5)	−0.051 (3)	0.018*
H3	0.2500	0.977 (5)	−0.031 (3)	0.018*
H4	−0.2500	0.974 (5)	0.531 (3)	0.018*
H5	−0.160 (3)	0.847 (3)	0.4696 (19)	0.018*
H6	−0.2500	0.775 (5)	0.553 (3)	0.018*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Sc1	0.0039 (4)	0.0042 (4)	0.0074 (4)	0.00004 (11)	−0.00071 (12)	−0.00001 (11)
F1	0.0058 (8)	0.0155 (11)	0.0122 (10)	0.000	0.000	−0.0013 (7)
F2	0.0118 (7)	0.0155 (7)	0.0088 (7)	−0.0003 (7)	−0.0023 (5)	−0.0033 (7)
F3	0.0120 (7)	0.0161 (7)	0.0081 (7)	0.0005 (7)	−0.0022 (5)	0.0035 (7)
F4	0.0047 (8)	0.0178 (11)	0.0129 (10)	0.000	0.000	−0.0006 (8)
F5	0.0156 (6)	0.0043 (8)	0.0204 (10)	0.0005 (6)	0.0004 (4)	−0.0001 (4)
N1	0.0131 (13)	0.0107 (15)	0.0076 (14)	0.000	0.000	0.0025 (17)
N2	0.0138 (14)	0.0090 (14)	0.0126 (14)	0.000	0.000	−0.0041 (17)

Geometric parameters (Å, º) top

Sc1—F2	1.9904 (12)	F5—Sc1^iv	2.0320 (19)
Sc1—F3	1.9919 (12)	N1—H1	0.91 (3)
Sc1—F1	2.0272 (7)	N1—H2	0.97 (4)
Sc1—F4	2.0273 (7)	N1—H3	0.86 (4)
Sc1—F5ⁱ	2.0320 (19)	N2—H4	0.84 (4)
Sc1—F5	2.0325 (19)	N2—H5	0.93 (3)
F1—Sc1ⁱⁱ	2.0272 (7)	N2—H6	0.99 (4)
F4—Sc1ⁱⁱⁱ	2.0273 (7)

F2—Sc1—F3	179.61 (9)	F1—Sc1—F5	90.14 (7)
F2—Sc1—F1	91.38 (6)	F4—Sc1—F5	89.92 (7)
F3—Sc1—F1	88.59 (6)	F5ⁱ—Sc1—F5	179.713 (18)
F2—Sc1—F4	88.79 (6)	Sc1ⁱⁱ—F1—Sc1	151.46 (10)
F3—Sc1—F4	91.24 (6)	Sc1ⁱⁱⁱ—F4—Sc1	151.82 (10)
F1—Sc1—F4	179.82 (7)	Sc1^iv—F5—Sc1	168.48 (8)
F2—Sc1—F5ⁱ	90.22 (6)	H1—N1—H2	100 (2)
F3—Sc1—F5ⁱ	90.17 (6)	H1—N1—H3	115 (2)
F1—Sc1—F5ⁱ	89.97 (7)	H2—N1—H3	125 (3)
F4—Sc1—F5ⁱ	89.97 (7)	H4—N2—H5	116 (2)
F2—Sc1—F5	89.52 (6)	H4—N2—H6	126 (3)
F3—Sc1—F5	90.10 (6)	H5—N2—H6	98 (2)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···F2	0.91 (3)	1.97 (3)	2.836 (2)	159 (2)
N1—H2···F3^v	0.97 (4)	2.11 (3)	2.858 (3)	132 (1)
N1—H3···F2^vi	0.86 (4)	2.21 (3)	2.853 (3)	131 (1)
N2—H4···F3^vii	0.84 (4)	2.24 (3)	2.867 (3)	132 (1)
N2—H5···F3	0.93 (3)	1.95 (3)	2.837 (2)	158 (2)
N2—H6···F2^viii	0.99 (4)	2.11 (3)	2.872 (4)	132 (1)

Symmetry codes: (v) −x+1/2, −y+3/2, z−1/2; (vi) x+1/2, −y+2, −z; (vii) x−1/2, −y+2, −z+1; (viii) −x−1/2, −y+3/2, z+1/2.

Experimental details

Crystal data
Chemical formula	NH₄ScF₄
M_r	139.00
Crystal system, space group	Orthorhombic, Pmcn
Temperature (K)	93
a, b, c (Å)	7.862 (2), 8.088 (2), 13.503 (4)
V (Å³)	858.6 (4)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	1.67
Crystal size (mm)	0.10 × 0.03 × 0.02

Data collection
Diffractometer	Rigaku/MSC CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 1999)
T_min, T_max	0.825, 0.970
No. of measured, independent and observed [I > 2σ(I)] reflections	5191, 847, 587
R_int	0.026
(sin θ/λ)_max (Å⁻¹)	0.602

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.028, 0.102, 1.11
No. of reflections	847
No. of parameters	75
H-atom treatment	Only H-atom coordinates refined
Δρ_max, Δρ_min (e Å⁻³)	0.40, −0.40

Computer programs: CrystalClear (Rigaku/MSC, 2005), CrystalClear, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg, 2001), SHELXL97.

Selected geometric parameters (Å, º) top

Sc1—F2	1.9904 (12)	Sc1—F4	2.0273 (7)
Sc1—F3	1.9919 (12)	Sc1—F5ⁱ	2.0320 (19)
Sc1—F1	2.0272 (7)	Sc1—F5	2.0325 (19)

F2—Sc1—F3	179.61 (9)	Sc1ⁱⁱ—F1—Sc1	151.46 (10)
F1—Sc1—F4	179.82 (7)	Sc1ⁱⁱⁱ—F4—Sc1	151.82 (10)
F5ⁱ—Sc1—F5	179.713 (18)	Sc1^iv—F5—Sc1	168.48 (8)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···F2	0.91 (3)	1.97 (3)	2.836 (2)	159 (2)
N1—H2···F3^v	0.97 (4)	2.11 (3)	2.858 (3)	132.0 (9)
N1—H3···F2^vi	0.86 (4)	2.21 (3)	2.853 (3)	131.3 (14)
N2—H4···F3^vii	0.84 (4)	2.24 (3)	2.867 (3)	132.1 (14)
N2—H5···F3	0.93 (3)	1.95 (3)	2.837 (2)	158 (2)
N2—H6···F2^viii	0.99 (4)	2.11 (3)	2.872 (4)	132.1 (9)

Symmetry codes: (v) −x+1/2, −y+3/2, z−1/2; (vi) x+1/2, −y+2, −z; (vii) x−1/2, −y+2, −z+1; (viii) −x−1/2, −y+3/2, z+1/2.

Bond valence parameters. top

Bond	s_(ij)	Σ s_(ij)
Sc F2	0.54
Sc F3	0.53
Sc F1	0.49
Sc F4	0.49
Sc F5	0.48
Sc F5	0.48
		3.00
F1 Sc	0.49 x 2	0.97
F2 Sc	0.54	0.54
F3 Sc	0.53	0.53
F4 Sc	0.49 x 2	0.97
F5 Sc	0.48
F5 Sc	0.48	0.96

s_(ij) values calculated for B = 0.37; Brese & O'Keeffe (1991) extrapolated.

Acknowledgements

We thank Professor Alex Slawin for X-ray data collection and the University of St Andrews for funding.

References

Brandenburg, K. (2001). DIAMOND. Version 2.1. Crystal Impact GbR, Bonn, Germany. Google Scholar
Brese, N. E. & O'Keeffe, M. (1991). Acta Cryst. B47, 192–197. CrossRef CAS Web of Science IUCr Journals Google Scholar
Bruker (1999). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Champarnaud-Mesjard, J. C. & Frit, B. (1992). Eur. J. Solid State Inorg. Chem. 29, 161–170. CAS Google Scholar
Courbion, G., Randrianohavy, J. V. & Rousseau, J. J. (1989). J. Solid State Chem. 81, 285–292. CrossRef CAS Web of Science Google Scholar
Dion, M., Ganne, M. & Tournoux, M. (1981). Mater. Res. Bull. 16, 1429–1435. CrossRef CAS Web of Science Google Scholar
Lapasset, J., Sciau, P., Moret, J. & Gros, N. (1986). Acta Cryst. B42, 258–262. CrossRef CAS IUCr Journals Google Scholar
Leblanc, M., Ferey, G., De Pape, R. & Teillet, J. (1985). Acta Cryst. C41, 657–660. CrossRef CAS Web of Science IUCr Journals Google Scholar
Rigaku/MSC (2005). CrystalClear. Rigaku/MSC Inc., The Woodlands, Texas, USA. Google Scholar
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. Release 97-2. University of Göttingen, Germany. Google Scholar
Stephens, N. F. & Lightfoot, P. (2006). Solid State Sci. 8, 197–202. Web of Science CSD CrossRef CAS Google Scholar
Stephens, N. F., Slawin, A. M. Z. & Lightfoot, P. (2004). Chem. Commun. pp. 614–615. CrossRef Google Scholar

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Volume 62| Part 12| December 2006| Pages i103-i105

doi:10.1107/S0108270106044520

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inorganic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Ammonium scandium tetra­fluoride

Comment

Experimental

Crystal data

Data collection

Refinement

Supporting information

Acknowledgements

References

inorganic compounds

Ammonium scandium tetrafluoride