Lithio­marsturite, LiCa2Mn2Si5O14(OH)

Yang, H.; Downs, R.T.; Yang, Y.W.

doi:10.1107/S1600536811047581

inorganic compounds

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Volume 67| Part 12| December 2011| Page i73

https://doi.org/10.1107/S1600536811047581

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Lithiomarsturite, LiCa₂Mn₂Si₅O₁₄(OH)

Hexiong Yang,^a ^* Robert T. Downs ^a and Yongbo W. Yang ^b

^aDepartment of Geosciences, University of Arizona, 1040 E. 4th Street, Tucson, Arizona 85721-0077, USA, and ^bDepartment of Chemsitry and Biochemistry, University of Arizona, 1306 E. University Blvd, Tucson, Arizona 85721-0041, USA
^*Correspondence e-mail: hyang@u.arizona.edu

(Received 19 September 2011; accepted 9 November 2011; online 16 November 2011)

Lithiomarsturite, ideally LiCa₂Mn₂Si₅O₁₄(OH), is a member of the pectolite–pyroxene series of pyroxenoids (hydropyroxenoids) and belongs to the rhodonite group. A previous structure determination of this mineral based on triclinic symmetry in space group P $[\overline{1}]$ by Peacor et al. [Am. Mineral. (1990), 75, 409–414] converged with R = 0.18 without reporting any information on atomic coordinates and displacement parameters. The current study redetermines its structure from a natural specimen from the type locality (Foote mine, North Carolina) based on single-crystal X-ray diffraction data. The crystal structure of lithiomarsturite is characterized by ribbons of edge-sharing CaO₆ and two types of MnO₆ octahedra as well as chains of corner-sharing SiO₄ tetrahedra, both extending along [110]. The octahedral ribbons are interconnected by the rather irregular CaO₈ and LiO₆ polyhedra through sharing corners and edges, forming layers parallel to ( $[\overline{1}]$ 1 $[\overline{1}]$ ), which are linked together by the silicate chains. Whereas the coordination environments of the Mn and Li cations can be compared to those of the corresponding cations in nambulite, the bonding situations of the Ca cations are more similar to those in babingtonite. In contrast to the hydrogen-bonding scheme in babingtonite, which has one O atom as the hydrogen-bond donor and a second O atom as the hydrogen-bond acceptor, our study shows that the situation is reversed in lithiomarsturite for the same two O atoms, as a consequence of the differences in the bonding environments around O atoms in the two minerals.

Related literature

For a previous structural study of lithiomartusite, see: Peacor et al. (1990 ). For other minerals of the rhodonite group, see: Liebau et al. (1959 ); Peacor & Niizeki (1963 ); Araki & Zoltai (1972 ); Kosoi (1976 ); Narita et al. (1975 ); Tagai et al. (1990 ); Orlandi et al. (1998 ); Armbruster (2000 ). For the definition of polyhedral distortion, see: Robinson et al. (1971 ). For bond-valence calculations, see: Brese & O'Keeffe (1991 ).

Experimental

Crystal data

LiCa₂Mn₂Si₅O₁₄(OH)
M_r = 578.44
Triclinic, $[P \overline 1]$
a = 7.6467 (3) Å
b = 11.7315 (6) Å
c = 6.8100 (3) Å
α = 91.874 (4)°
β = 94.465 (3)°
γ = 105.933 (3)°
V = 584.72 (5) Å³
Z = 2
Mo Kα radiation
μ = 3.65 mm⁻¹
T = 293 K
0.06 × 0.05 × 0.05 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick 2005 ) T_min = 0.811, T_max = 0.839
14045 measured reflections
4191 independent reflections
3317 reflections with I > 2σ(I)
R_int = 0.035

Refinement

R[F² > 2σ(F²)] = 0.033
wR(F²) = 0.078
S = 1.03
4191 reflections
230 parameters
Only H-atom coordinates refined
Δρ_max = 1.26 e Å⁻³
Δρ_min = −0.56 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O11—H1⋯O1ⁱ	1.07 (4)	1.44 (4)	2.462 (3)	157 (3)
Symmetry code: (i) -x+1, -y, -z+1.

Data collection: APEX2 (Bruker, 2004 ); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XtalDraw (Downs & Hall-Wallace, 2003 ); software used to prepare material for publication: publCIF (Westrip, 2010 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536811047581/ru2015sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536811047581/ru2015Isup2.hkl

checkCIF report

Comment top

Lithiomarsturite, ideally LiCa₂Mn₂Si₅O₁₄(OH), is a member of the pectolite-pyroxene series of pyroxenoids (hydropyroxenoids) and belongs to the rhodonite group, which includes rhodonite MnSiO₃, babingtonite Ca₂Fe²⁺Fe³⁺Si₅O₁₄(OH), manganbabingtonite Ca₂Mn²⁺Fe³⁺Si₅O₁₄(OH), scandiobabingtonite (Ca,Na)₂(Fe²⁺,Mn)(Sc,Fe³⁺)Si₅O₁₄(OH), nambulite LiMn₄Si₅O₁₄(OH), natronambulite NaMn₄Si₅O₁₄(OH), marsturite NaCa₂Mn₂Si₅O₁₄(OH), and lithiomarsturite. Thus far, only the crystal structures of four minerals in this group have been determined, including rhodonite (Liebau et al. 1959; Peacor & Niizeki, 1963), babingtonite (Araki & Zoltai, 1972; Kosoi, 1976), nambulite (Narita et al., 1975), and scandiobabingtonite (Orlandi et al., 1998).

Lithiomarsturite was first described by Peacor et al. (1990) from the Foote mine in North Carolina, with space group P1, and unit-cell parameters a = 7.652 (3), b = 12.119 (3), c = 6.805 (2) Å, α = 85.41 (2), β = 94.42 (3), γ = 111.51 (2)°. The reported empirical chemical formula, derived from electron and ion microprobe analyses, is Li_1.01Ca_1.98Mn_1.35Fe_0.56Mg_0.10H_1.00Si_5.00O₁₅, which can be simplified as LiCa₂Mn₂Si₅O₁₄(OH). Although Peacor et al. (1990) showed that this mineral belongs to the rhodonite group, they did not provide any detailed information on atomic coordinates and displacement parameters, because their structure refinement with 2338 single-crystal X-ray diffraction intensity data converged with R = 18%, due probably to the presence of common chain-periodicity faults. Since then, no further study on lithiomarsturite has been reported. This study presents the first structure refinement of lithiomarsturite based on single-crystal X-ray diffraction data.

Lithiomarsturite is isotypic with nambulite. Its structure is characterized by ribbons of edge-sharing Ca1O₆, Mn1O₆ and Mn2O₆ octahedra and chains of corner-sharing SiO₄ tetrahedra, both extending along [110] (Fig. 1). The octahedral ribbons are interconnected by the Ca2O₈ and Li1O₆ polyhedra through sharing corners and edges to form layers parallel to (1 1 1), which are linked together by the silicate chains. Whereas the Ca1, Mn1, and Mn2 octahedra are fairly regular, the Ca2O₈ and Li1O₆ polyhedra are rather irregular. The average Mn1—O and Mn2—O bond distances are 2.202 and 2.172 Å, respectively, both of which are slightly shorter than the corresponding Mn—O distances (2.233 and 2.188 Å) in nambulite (Narita et al., 1975). Within 2.9 Å, Li is coordinated to six O atoms in lithiomarsturite (the next nearest O atom is at 3.12 Å), with an average Li—O distance of 2.322 Å, but to eight O atoms in nambulite, with an average Li—O distance of 2.485 Å (Narita et al., 1975). This difference can be ascribed mostly to the replacement of the significant amount of Li (43%) by Na in nambulite examined by Narita et al. (1975).

The two Ca polyhedra in lithiomarsturite are better compared to those in babingtonite (Tagai et al., 1990; Armbruster, 2000). The Ca1O₆ octahedra in lithiomarsturite, on the one hand, are much less distorted than those in babingtonite in terms of both the octahedral angle variance (OAV) and quadratic elongation (OQE) (Robinson et al., 1971), which are 146 and 1.040, respectively, for the former, and 311 and 1.092 for the latter. The greater distortion of the Ca1 octahedra in babingtonite is understandable, because they share edges with the Fe1O₆ and Fe2O₆ octahedra in the octahedral ribbons, which are primarily occupied by cations with different sizes and charges (Fe²⁺ and Fe³⁺, respectively). In contrast, both Mn1O₆ and Mn2O₆ octahedra that share edges with the Ca1O₆ octahedra in lithiomarsturite (Fig. 1) are filled with the same kind of cation (Mn²⁺). On the other hand, the Ca2 cations in lithiomarsturite and babingtonite exhibit similar coordination environments, both of which have seven Ca—O bond lengths shorter than 2.65 Å and one Ca—O bond length greater than 2.84 Å. If we only take the seven shorter Ca—O bond lengths into account, then a calculation of the bond-valence sums using the parameters given by Brese & O'Keeffe (1991) yields 2.03 and 2.09 v.u. for the Ca2 cations in lithiomarsturite and babingtonite, respectively, suggesting that the Ca2 cations may be only bonded to seven, rather eight, O atoms in these two minerals. At least, this should be the case for Ca2 in lithiomarsturite, because the next nearest O atom (except the seven closer O atoms) is 3.059 Å away.

Very intriguingly, both previous neutron and X-ray diffraction studies (Tagai et al., 1990; Armbruster, 2000) have demonstrated that the hydrogen bonding in babingtonite is between O1 and O11, with the former as the H-donor and the latter as the H-acceptor. However, our study shows the opposite case for lithiomarsturite, in which O11 is the H-donor and O1 the H-acceptor. This difference is the direct result of the change in the bonding environments around O1 and O11 in the two minerals. In babingtonite, both O1 and O11 are bonded to two non-hydrogen cations, with O1 to Si1 and Ca1, and O11 to Si4 and Fe2, but in lithiomarsturite, O1 is bonded to three non-hydrogen cations (Si1, Ca1, and Li1), and O11 to two (Si4 and Mn2). Note that Fe2 in babingtonite is chiefly trivalent Fe³⁺, whereas Mn2 in lithiomarsturite is essentially divalent Mn²⁺. As a consequence of this coupled effect, the more underbonded O1 (relative to O11) in babingtonite becomes less underbonded in lithiomarsturite. Because the more underbonded O atom will be more tightly bonded to the H atom to better satisfy its bond-valence requirement, we see the change from O1 being the H-donor in babingtonite to O11 in lithiomarsturite. Accordingly, it is most likely that other members of the rhodonite group that contain Li or Na as an essential component, such as nambulite, natronambulite, and marsturite, may all behave as lithiomarsturite in terms of the hydrogen bonding scheme, with O11 being the H-donor and O1 the H-acceptor. For some specific chemical compositions, nevertheless, it may also be possible that the H atom is situated halfway between O1 and O11 or hops between the two positions.

Related literature top

For lithiomarsturite, see: Peacor et al. (1990). For other minerals of the rhodonite group, see: Liebau et al. (1959); Peacor & Niizeki (1963); Araki & Zoltai (1972); Kosoi (1976); Narita et al. (1975); Tagai et al. (1990); Orlandi et al. (1998); Armbruster (2000). For the definition of polyhedral distortion, see: Robinson et al. (1971). For bond-valence calculations, see: Brese & O'Keeffe (1991).

Experimental top

The lithiomarsturite sample used in this study is from the type locality: the Foote mine, Kings Mountains, North Carolina, USA, and is in the collection of the RRUFF project (deposition No. R100094; http://rruff.info). The chemical composition analyzed by Peacor et al. (1990) was adopted for the structure refinement. To keep consistent with the unit-cell settings for other minerals in the rhodonite group, such as rhodonite, babingtonite, and nambulite, we have adopted a unit-cell setting that differs from the one given by Peacor et al. (1990). The matrix for the transformation from the unit-cell setting of Peacor et al. (1990) to ours is [-1 0 0 / 1 1 0 / 0 0 - 1]. The labeling scheme of the atoms in lithiomarsturite is similar to that for numbulite (Narita et al., 1975).

Structure description top

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XtalDraw (Downs & Hall-Wallace, 2003); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top

Fig. 1. Crystal structure of lithiomarsturite. The green tetrahedra represent SiO₄ groups. Large gray, medium yellow, and small bright blue sphares represent Ca2, Li1, H1 atoms, respectively. Both ribbons of edge-sharing octahedra and chains of vertex-sharing tetrahedra run parallel to [110].

Lithiomarsturite top

Crystal data top

LiCa₂Mn₂Si₅O₁₄(OH)	Z = 2
M_r = 578.44	F(000) = 568
Triclinic, P1	D_x = 3.285 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.6467 (3) Å	Cell parameters from 2086 reflections
b = 11.7315 (6) Å	θ = 3.5–28°
c = 6.8100 (3) Å	µ = 3.65 mm⁻¹
α = 91.874 (4)°	T = 293 K
β = 94.465 (3)°	Cube, light gray
γ = 105.933 (3)°	0.06 × 0.05 × 0.05 mm
V = 584.72 (5) Å³

Data collection top

Bruker APEXII CCD area-detector diffractometer	4191 independent reflections
Radiation source: fine-focus sealed tube	3317 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.035
φ and ω scan	θ_max = 32.6°, θ_min = 3.0°
Absorption correction: multi-scan (SADABS; Sheldrick 2005)	h = −11→11
T_min = 0.811, T_max = 0.839	k = −17→17
14045 measured reflections	l = −10→10

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F² > 2σ(F²)] = 0.033	Only H-atom coordinates refined
wR(F²) = 0.078	w = 1/[σ²(F_o²) + (0.0354P)² + 0.2944P] where P = (F_o² + 2F_c²)/3
S = 1.03	(Δ/σ)_max = 0.006
4191 reflections	Δρ_max = 1.26 e Å⁻³
230 parameters	Δρ_min = −0.56 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0023 (5)

Crystal data top

LiCa₂Mn₂Si₅O₁₄(OH)	γ = 105.933 (3)°
M_r = 578.44	V = 584.72 (5) Å³
Triclinic, P1	Z = 2
a = 7.6467 (3) Å	Mo Kα radiation
b = 11.7315 (6) Å	µ = 3.65 mm⁻¹
c = 6.8100 (3) Å	T = 293 K
α = 91.874 (4)°	0.06 × 0.05 × 0.05 mm
β = 94.465 (3)°

Data collection top

Bruker APEXII CCD area-detector diffractometer	4191 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick 2005)	3317 reflections with I > 2σ(I)
T_min = 0.811, T_max = 0.839	R_int = 0.035
14045 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.033	0 restraints
wR(F²) = 0.078	Only H-atom coordinates refined
S = 1.03	Δρ_max = 1.26 e Å⁻³
4191 reflections	Δρ_min = −0.56 e Å⁻³
230 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
Li1	0.6570 (12)	0.1276 (10)	0.3338 (12)	0.067 (3)
Ca1	0.80601 (7)	0.94132 (4)	0.13944 (7)	0.01028 (10)
Ca2	0.23393 (7)	0.52331 (5)	0.28673 (7)	0.01254 (10)
Mn1	0.59386 (5)	0.64710 (3)	0.06116 (5)	0.00721 (8)
Mn2	0.04394 (5)	0.23677 (3)	0.18152 (5)	0.00722 (8)
Si1	0.28154 (9)	0.05291 (6)	0.34656 (9)	0.00840 (13)
Si2	0.46371 (9)	0.32017 (6)	0.42345 (9)	0.00704 (12)
Si3	0.80739 (9)	0.44983 (6)	0.21522 (9)	0.00627 (12)
Si4	0.99738 (9)	0.71828 (6)	0.30096 (9)	0.00756 (12)
Si5	0.33975 (9)	0.84444 (6)	0.10838 (9)	0.00758 (12)
O1	0.2071 (3)	−0.00760 (16)	0.5439 (3)	0.0155 (4)
O2	0.1231 (2)	0.06860 (15)	0.1893 (3)	0.0116 (3)
O3	0.4399 (2)	0.17592 (14)	0.4144 (2)	0.0104 (3)
O4	0.3253 (2)	0.34697 (15)	0.2519 (2)	0.0108 (3)
O5	0.5434 (2)	0.62430 (15)	0.3623 (2)	0.0113 (3)
O6	0.6815 (2)	0.37564 (15)	0.3790 (2)	0.0107 (3)
O7	0.9617 (2)	0.39040 (15)	0.1616 (3)	0.0116 (3)
O8	0.6769 (2)	0.47395 (15)	0.0349 (2)	0.0098 (3)
O9	0.9282 (2)	0.57625 (14)	0.3373 (2)	0.0103 (3)
O10	0.8758 (2)	0.75807 (15)	0.1281 (3)	0.0118 (3)
O11	0.9976 (3)	0.21112 (16)	0.4905 (3)	0.0170 (4)
O12	0.2081 (2)	0.74122 (15)	0.2372 (2)	0.0109 (3)
O13	0.5208 (2)	0.80942 (16)	0.0672 (3)	0.0127 (3)
O14	0.7740 (2)	0.13142 (15)	0.0878 (2)	0.0121 (3)
O15	0.3966 (2)	0.96997 (15)	0.2470 (3)	0.0135 (3)
H1	0.938 (5)	0.117 (3)	0.480 (5)	0.040*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Li1	0.060 (5)	0.126 (8)	0.046 (4)	0.067 (6)	0.036 (4)	0.035 (5)
Ca1	0.0128 (2)	0.0071 (2)	0.0100 (2)	0.00122 (17)	0.00179 (16)	−0.00081 (16)
Ca2	0.0095 (2)	0.0128 (2)	0.0139 (2)	0.00159 (18)	−0.00014 (17)	−0.00341 (17)
Mn1	0.00686 (16)	0.00675 (16)	0.00782 (15)	0.00160 (12)	0.00084 (12)	−0.00022 (12)
Mn2	0.00669 (16)	0.00570 (15)	0.00900 (16)	0.00153 (12)	0.00000 (12)	−0.00028 (12)
Si1	0.0086 (3)	0.0066 (3)	0.0092 (3)	0.0012 (2)	−0.0004 (2)	−0.0006 (2)
Si2	0.0065 (3)	0.0060 (3)	0.0078 (3)	0.0006 (2)	0.0005 (2)	0.0000 (2)
Si3	0.0060 (3)	0.0054 (3)	0.0070 (3)	0.0011 (2)	0.0002 (2)	−0.0002 (2)
Si4	0.0076 (3)	0.0058 (3)	0.0088 (3)	0.0012 (2)	0.0005 (2)	−0.0002 (2)
Si5	0.0071 (3)	0.0072 (3)	0.0085 (3)	0.0021 (2)	0.0009 (2)	0.0000 (2)
O1	0.0164 (9)	0.0155 (9)	0.0103 (8)	−0.0036 (7)	0.0035 (7)	0.0019 (7)
O2	0.0107 (8)	0.0119 (8)	0.0118 (8)	0.0030 (7)	−0.0007 (6)	−0.0001 (6)
O3	0.0111 (8)	0.0059 (7)	0.0135 (8)	0.0020 (6)	−0.0011 (6)	−0.0011 (6)
O4	0.0096 (8)	0.0102 (8)	0.0118 (8)	0.0025 (6)	−0.0024 (6)	0.0001 (6)
O5	0.0112 (8)	0.0108 (8)	0.0109 (8)	0.0018 (7)	0.0014 (6)	−0.0026 (6)
O6	0.0085 (8)	0.0119 (8)	0.0104 (7)	0.0001 (6)	0.0017 (6)	0.0028 (6)
O7	0.0100 (8)	0.0103 (8)	0.0155 (8)	0.0044 (6)	0.0033 (6)	−0.0016 (6)
O8	0.0085 (7)	0.0114 (8)	0.0093 (7)	0.0024 (6)	−0.0003 (6)	0.0014 (6)
O9	0.0123 (8)	0.0052 (7)	0.0123 (8)	0.0010 (6)	−0.0007 (6)	−0.0002 (6)
O10	0.0107 (8)	0.0114 (8)	0.0142 (8)	0.0043 (7)	0.0003 (6)	0.0037 (6)
O11	0.0269 (10)	0.0094 (8)	0.0118 (8)	−0.0008 (8)	0.0078 (7)	−0.0032 (6)
O12	0.0078 (8)	0.0118 (8)	0.0126 (8)	0.0010 (6)	0.0019 (6)	0.0036 (6)
O13	0.0109 (8)	0.0127 (8)	0.0164 (8)	0.0053 (7)	0.0046 (7)	0.0018 (7)
O14	0.0138 (8)	0.0121 (8)	0.0100 (8)	0.0032 (7)	−0.0016 (6)	0.0029 (6)
O15	0.0128 (8)	0.0099 (8)	0.0171 (8)	0.0029 (7)	0.0006 (7)	−0.0036 (6)

Geometric parameters (Å, º) top

Li1—O14	1.956 (7)	Mn2—O14^vii	2.1304 (18)
Li1—O3	2.004 (7)	Mn2—O11^vii	2.1778 (18)
Li1—O1ⁱ	2.121 (8)	Mn2—O4	2.1912 (17)
Li1—O15ⁱⁱ	2.336 (11)	Mn2—O2	2.2180 (18)
Li1—O11	2.642 (10)	Mn2—O10^v	2.2396 (18)
Li1—O6	2.869 (11)	Si1—O2	1.6068 (18)
Ca1—O1ⁱⁱⁱ	2.2873 (19)	Si1—O1	1.6105 (19)
Ca1—O13	2.3074 (19)	Si1—O3	1.6346 (18)
Ca1—O14^iv	2.3441 (18)	Si1—O15ⁱⁱ	1.6431 (19)
Ca1—O2^v	2.3506 (18)	Si2—O5ⁱⁱⁱ	1.5891 (18)
Ca1—O10	2.3534 (18)	Si2—O4	1.6119 (17)
Ca1—O2^vi	2.4648 (18)	Si2—O3	1.6502 (17)
Ca2—O7^vii	2.3119 (18)	Si2—O6	1.6690 (18)
Ca2—O8^v	2.3429 (18)	Si3—O7	1.5856 (19)
Ca2—O5	2.3455 (18)	Si3—O8	1.6035 (17)
Ca2—O4	2.3688 (18)	Si3—O6	1.6428 (18)
Ca2—O6ⁱⁱⁱ	2.4857 (18)	Si3—O9	1.6709 (18)
Ca2—O9^vii	2.6230 (19)	Si4—O10	1.6033 (18)
Ca2—O12	2.6477 (18)	Si4—O11^viii	1.6129 (19)
Mn1—O13	2.1268 (18)	Si4—O9	1.6374 (18)
Mn1—O5	2.1281 (17)	Si4—O12^ix	1.6542 (19)
Mn1—O10	2.1952 (18)	Si5—O13	1.5900 (19)
Mn1—O8^v	2.2010 (17)	Si5—O14^v	1.6125 (17)
Mn1—O4^v	2.2635 (18)	Si5—O15	1.6560 (18)
Mn1—O8	2.2941 (18)	Si5—O12	1.6695 (18)
Mn2—O7^vii	2.0704 (17)

O2—Si1—O1	113.72 (10)	O7—Si3—O9	102.31 (9)
O2—Si1—O3	114.40 (9)	O8—Si3—O9	111.55 (9)
O1—Si1—O3	107.47 (9)	O6—Si3—O9	104.52 (9)
O2—Si1—O15ⁱⁱ	110.10 (10)	O10—Si4—O11^viii	112.69 (11)
O1—Si1—O15ⁱⁱ	107.53 (10)	O10—Si4—O9	113.18 (9)
O3—Si1—O15ⁱⁱ	102.87 (10)	O11^viii—Si4—O9	107.23 (10)
O5ⁱⁱⁱ—Si2—O4	115.99 (10)	O10—Si4—O12^ix	109.06 (9)
O5ⁱⁱⁱ—Si2—O3	114.15 (9)	O11^viii—Si4—O12^ix	109.23 (10)
O4—Si2—O3	108.16 (9)	O9—Si4—O12^ix	105.14 (9)
O5ⁱⁱⁱ—Si2—O6	103.34 (9)	O13—Si5—O14^v	113.97 (10)
O4—Si2—O6	111.94 (9)	O13—Si5—O15	108.72 (10)
O3—Si2—O6	102.39 (9)	O14^v—Si5—O15	106.07 (9)
O7—Si3—O8	116.88 (10)	O13—Si5—O12	110.06 (10)
O7—Si3—O6	111.46 (10)	O14^v—Si5—O12	110.83 (9)
O8—Si3—O6	109.28 (9)	O15—Si5—O12	106.85 (9)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O11—H1···O1ⁱ	1.07 (4)	1.44 (4)	2.462 (3)	157 (3)

Symmetry code: (i) −x+1, −y, −z+1.

Experimental details

Crystal data
Chemical formula	LiCa₂Mn₂Si₅O₁₄(OH)
M_r	578.44
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	7.6467 (3), 11.7315 (6), 6.8100 (3)
α, β, γ (°)	91.874 (4), 94.465 (3), 105.933 (3)
V (Å³)	584.72 (5)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	3.65
Crystal size (mm)	0.06 × 0.05 × 0.05

Data collection
Diffractometer	Bruker APEXII CCD area-detector
Absorption correction	Multi-scan (SADABS; Sheldrick 2005)
T_min, T_max	0.811, 0.839
No. of measured, independent and observed [I > 2σ(I)] reflections	14045, 4191, 3317
R_int	0.035
(sin θ/λ)_max (Å⁻¹)	0.759

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.033, 0.078, 1.03
No. of reflections	4191
No. of parameters	230
H-atom treatment	Only H-atom coordinates refined
Δρ_max, Δρ_min (e Å⁻³)	1.26, −0.56

Computer programs: APEX2 (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), XtalDraw (Downs & Hall-Wallace, 2003), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O11—H1···O1ⁱ	1.07 (4)	1.44 (4)	2.462 (3)	157 (3)

Symmetry code: (i) −x+1, −y, −z+1.

Acknowledgements

The authors gratefully acknowledge support of this study by the Arizona Science Foundation.

References

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