Crystal structures of strontium and barium ethylenediaminetetraacetato cobaltates(III), Sr[CoEdta]2·9H2O and Ba[CoEdta]2·8H2O: Comparison of the structures of complexes in the series M’[CoEdta]2·nH2O (M’ = Mg, Ca, Sr, Ba; n = 7–10)

Cobalt(III) complexes, namely, Sr[CoEdta]₂·9H₂O (I) and Ba[CoEdta]₂·8H₂O (II) (where Edta ^4- is the ethylenediaminetetraacetate ion), are synthesized. The crystal structures of these compounds are determined using X-ray diffraction. Crystals of compound I are triclinic, a = 6.514(1) Å, b = 11.410(2) Å, c = 12.317(2) Å, α = 67.87(1)°, β = 88.73(2)°, γ = 84.22(2)°, V = 843.63(3) ų, Z = 1, space group P1, and R = 0.0295 for 4130 reflections with I > 2σ(I). Crystals of compound II are monoclinic, a = 6.543(2) Å, b = 12.895(3) Å, c = 19.489(4) Å, β = 95.24(3)°, V = 1637.5(5) ų, Z = 2, space group P2₁, and R = 0.050 for 3016 reflections with |F| > 3σ(|F|). The structures of compounds I and II are compared with those of the previously studied complexes Mg[CoEdta]₂·10H₂O (III) and Ca[CoEdta]₂·7H₂O (IV). The crystal structure of the cobalt(III) complex with the strontium cation (I) is topologically similar to the crystal structure of cobalt(III) complex with the calcium cation (IV). The former structure is built up of the two symmetrically independent homochiral anionic complexes [CoEdta]^? (A _I and B _I), the aqua cations [Sr(H₂O)₈]²⁺, and the molecules of crystalization water w _cr. The structure of compound II involves two independent anions [CoEdta]^? (A _II and B _II) with different chiralities (i.e., they are kryptoracemates). The A _II anions are linked via the barium cations into {Ba(H₂O)₇[CoEdta]} _1∞ ⁺ chain agglomerates due to the incorporation of two terminal oxygen atoms O_u of the anions neighboring in the chain into the coordination sphere of the barium atom. All four structures (I–IV) contain stacks composed of the [CoEdta]^? homochiral anions forming layers aligned parallel to the (001) plane. The aqua cations [Sr(H₂O)₈]²⁺, [Mg(H₂O)₆]²⁺, and [Ca(H₂O)₇]²⁺ or the partially hydrated barium cations [Ba(H₂O)₇(O_u)₂]²⁺ (in structure II), as well as water molecules w _cr, are located between the anion layers. The octahedral environment of the cobalt(III) atoms consists of donor atoms (2N and 4O) of the Edta ^4? ligand. The Co-N bonds in the A _I, B _I, A _II, and B _II anions [the mean bond lengths are 1.927(4), 1.921(4), 1.910(6), and 1.921(6) Å, respectively] are considerably longer than the Co-O bonds [the mean bond lengths are 1.908(5), 1.902(5), 1.904(6), and 1.908(6) Å, respectively]. The mean distances Sr-O_w and Ba-O_w in the strontium and barium polyhedra are 2.609(4) and 2.834(8) Å, respectively. The mean distance Ba-O_u is 2.814(7) Å.     

Modular structure of a sodium-rich analogue of eudialyte with the doubled c-parameter and the R3 symmetry

The structure of a new sodium-rich representative of the eudialyte group with the ideal formula (Na,Sr, K)₃₅Ca₁₂Fe₃Zr₆TiSi₅₁O₁₄₄(O,OH,H₂O)₉Cl₃ was established by the X-ray diffraction analysis (R = 0.054 based on 3503 |F|). The unit-cell parameters are a = 14.239(1), c = 60.733(7) Å, V = 10663.9 ų, sp. gr. R3. The mineral structure is characterized by in-layer order of cations resulting in doubling of the c-parameter and the formation of two modules, the composition and the structure of one of which corresponds to eudialyte (with an impurity of kentbrooksite), the prototype of the second module is alluaivite. Lowering of the symmetry is caused by ordering of Ca atoms and the Ca-replacing elements in the alluaivite module and by the displacements of the alkali cations from the m plane.     

Crystal structures of double vanadates, Ca9 R(VO4)7 ⋅ III. R = Nd, Sm, Gd, or Ce

The crystal structures of Ca₉ R(VO₄)₇ (R = Nd (I), Sm (II), or Gd (III)) were studied by the Rietveld method. The compounds are isostructural to Ca₃(VO₄)₂ and are crystallized in the trigonal system (sp. gr. R3c, Z = 6). The unit-cell parameters are as follows: for I, a = 10.8720(5) Å, c = 38.121(1) Å; for II, a = 10.8652(5) Å, c = 38.098(1) Å; and for III, a = 10.8631(5) Å, c = 38.072(1) Å. In the structures of I and II, the M(1), M(2), and M(3) positions are statistically occupied by the rare-earth cations and calcium anions. In the structure of III, the Gd³⁺ cations occupy the _M(1) and _M(2) positions. The distributions of the R ³⁺ cations over the positions are characteristic of each structure. The composition of the cerium-ontaining compound Ca_9.81Ce_0.42(VO₄)₇ (a = 10.8552(5) Å, c = 38.037(1) Å) was refined and its crystal structure was solved from the X-ray powder data. In this compound, cerium atoms are in the oxidation states +3 and +4.     

Structural characteristics of Na,Fe-decationated eudialyte with the symmetry <Emphasis Type="Italic">R</Emphasis>3

The crystal structure of a new highly decationated representative of the eudialyte group has been established (R = 0.055, 1734 |F|). The mineral is described by the simplified formula (H₃O)₉Na₂(K, Ba,Sr)₂Ca₆Zr₃[Si₂₆O₆₆(OH)₆](OH)₃Cl · H₂O (Z = 3). The unit-cell parameters are a = 14.078(3) Å, c = 31.24(1) Å; V = 5362 ų; sp. gr. R3. Being chemically and structurally related to the hydrated analogues studied previously (in particular, to potassium oxonium eudialyte), the new mineral differs from its analogues in that it has a higher degree of Na-and Fe-cation depletion. The replacement of 3/4 of Na cations by loose and mobile H₃O groups results in structure destabilization, which is seen from the high values of the thermal parameters of the atoms and the loss of the symmetry plane.     

New Data on Isomorphism in Eudialyte-Group Minerals. I. Crystal Structure of Titanium-Rich Eudialyte from the Kovdor Alkaline Massif

An abnormally titanium-rich mineral of the eudialyte group was studied by IR spectroscopy and X-ray diffraction. The trigonal unit cell parameters are a = 14.165(1) Å, c = 30.600(5) Å, V = 5317.23(4) ų, sp. gr. R3m. The crystal structure was refined to R = 0.034 with anisotropic displacement parameters using 2530 reflections with F > 3σ(F). The idealized formula of the mineral (Z = 3) is Na₈(H₃O)₅(K,Ce,Sr)₂Ca₆Zr₂Ti_1.2(Fe,Mn)_0.6Si₂₆O₇₂(OH)₂Cl · 4H₂O. At the ratio Zr: Ti ~ 2: 1, titanium atoms lie in four sites and are not predominant in any of them. Another distinguishing feature of the mineral is the structural separation of chemical elements, such that K, Sr, and Ce cations and H₃O groups are randomly distributed between four split sites to form polyhedra with different volumes. The isomorphism of Zr and Ti in eudialyte-group minerals is discussed.     

Crystal structure of calcium trans-N-(nitrilotriacetato)(pyridine-2-carboxylato)cobaltate(III) hexahydrate, Ca[Co(Nta)(Pic)]2] · 6H2O

Crystals of Ca[Co^III (Nta)(Pic)]₂ · 6H₂O (I) (where Nta ^3? and Pic ^? are the nitrilotriacetate and picolinate ions, respectively) are prepared and characterized by the X-ray diffraction technique. Crystals I are monoclinic, a = 18.599(4) Å, b = 12.556(3) Å, c = 14.042(3) Å, β = 102.90(3)°, V = 3196(1) ų, Z = 4, space group P2₁/c, R1 = 0.0278, wR2 = 0.0716, and Goof = 1.054 for 4982 reflections with I > 2σ(I). Structure I is built of the { Ca(H₂O)₄[Co(Nta)(Pic)]₂{ _1∞ polymer ribbons and molecules of crystallization water. One of the two symmetrically independent anionic complexes (B) is included in the chain and alternates with cationic units, whereas the other anionic complex (A) forms a branch of this chain. The cationic and anionic units are interlinked via the interactions of the Ca²⁺ cations with the carbonyl atoms of the main (Nta ^3?) and additional (Pic ^?1) ligands. The octahedral environment of the Co(III) atoms consists of donor atoms of the Nta ^3? (N + 3O) and Pic ^? (N + O) ligands. The coordination polyhedron of the Ca atom (pentagonal bipyramid) includes two carbonyl O atoms of two Nta ^3? ligands, one O_Pic atom, and four O_w atoms of water molecules.     

Crystal structure of catena-poly[diaqua(μ-iminodiacetato-N,O,O′: O″)cobalt(II)]

The crystal structure of the [Co(C₄H₅NO₄)(H₂O)₂] complex has been determined by X-ray diffraction analysis (λMo, R = 0.0237 for 768 reflections). The crystals are orthorhombic, a = 14.345(1) Å, b = 5.234(1) Å, c = 9.780(1) Å, Z = 4, d _calcd = 2.045 g cm^?3, and space group Pca2₁. The donor atoms (one N and two O atoms) of the iminodiacetate ion (Ida) are located on the same octahedron face around the Co atom [Co-N, 2.120(3) Å; Co-O, 2.063(3) and 2.151(3) Å]. The O atoms of two water molecules are in the trans positions relative to the O atoms of the carboxylate groups [Co-O, 2.126(3) and 2.157(3) Å]. The sixth coordination site is occupied by the O atom of the adjacent Ida ion [Co-O, 2.054(3) Å], which results in the formation of infinite chains in the structure.     

Crystal structure of [N-(2-carbamoylethyl)iminodiacetato]-aqua(1,10-phenanthroline)cobalt(III) chloride 3.5 hydrate

The crystal structure of [N-(2-carbamoylethyl)iminodiacetato]-aqua(1,10-phenanthroline) cobalt(III) chloride 3.5 hydrate [Co(Ceida)(H₂O)(Phen)Cl · 3.5H₂O (I) has been determined by ¹H NMR technique and X-ray diffraction analysis. The crystals are triclinic, a = 10.352(2) Å, b = 12.534(3) Å, c = 20.665(4) Å, α = 107.02(3)°, β = 92.22(3)°, γ = 111.63(3)°, Z = 4, space group $P\bar 1$ , andR = 0.0438. The unit cell involves two crystallographically nonequivalent but virtually identical cationic complexes [Co(Ceida)(H₂O)(Phen)]⁺. The tridentate chelate ligand Ceida ^2? (N + 2O) occupies the face in the coordination octahedron of the Co atom, and the propionamide group remains free. The mean bond lengths are as follows: Co-O_Ceida, 1.876 Å; Co-N_Ceida, 1.981 Å; Co-N_Phen, 1.945 Å; and Co-O_w, 1.915 Å. In the structure, the arrangement of cationic complexes and certain water molecules exhibits a pseudosymmetry (the 2₁ axis). The cations and water molecules are located in the layers, and the anions are arranged between the layers. The structural elements are linked by hydrogen bonds and van der Waals interactions.     

Crystal structure of litvinskite: A new natural representative of the lovozerite group

A new representative of the lovozerite group—Na, Zr, Mn-silicate litvinskite (Na, H₂O, □) ₃(□, Na, Mn²⁺)Zr[Si₆O₁₂(OH)₃(OH, O)₃]—was discovered in ultraagpaitic pegmatites from the Lovozero massif. The crystal structure of the mineral was solved on an automated Syntex P $\bar 1$ diffractometer (MoK _α radiation, 1398 reflections, 2θ/θ scanning technique, anisotropic refinement to R _hkl = 0.065). The unit-cell parameters are a = 10.589(7) Å, b = 10.217(8) Å, c = 7.355(5) Å, β = 92.91(5)°, V = 794.6(9) ų, sp. gr. Cm, Z = 2, d _calcd = 2.63 g/cm³. The structure of the mineral consist of a three-dimensional framework of discrete six-membered rings of Si-tetrahedra linked to isolated Zr-octahedra. The framework cavities are occupied by Na cations. The litvinskite composition and the structure differ from all known natural and synthetic compounds of the lovozerite group, which supports the assumption about diversity of mineral types in this group.     

Crystal and molecular structure of barium cyclohexane-1,2-diamine-<Emphasis Type="Italic">N,N,N′,N′</Emphasis>-tetraacetatonickeloate decahydrate Ba[Ni(<Emphasis Type="Italic">Cdta</Emphasis>)] · 10H<Subscript>2</Subscript>O

The X-ray diffraction study of Ba[Ni(Cdta)] · 10H₂O is performed (R1 = 0.0441 for 5136 observed reflections). The crystals are triclinic, a = 8.833(2) Å, b = 9.025(2) Å, c = 16.922(3) Å, α = 80.56(3)°, β = 82.77(3)°, γ = 76.98(3)°, Z = 2, and space group \(P\bar 1\). The crystal is built of the [Ni(Cdta)]^2? anionic complexes, the [Ba(H₂O)₆]²⁺ hydrated cations, and crystallization water molecules. The distorted octahedral coordination of the Ni atom includes two N and four O atoms of the Cdta^4? ligand (mean Ni-N, Ni-O_G, and Ni-O_R re 2.080, 2.082, and 2.036 Å, respectively). The irregular nine-fold coordination of the Ba atom consists of six O atoms of water molecules and three O(Cdta) atoms from three anionic complexes (Ba—O, 2.715–3.090 Å). With consideration for the bonds with three Ba atoms, the Cdta^4? ligand is octadentate (2N + 6O) and fulfills the pentadentate μ₄-bridging function. The structural units are linked through an extended network of hydrogen bonds.     

Crystal structure of double vanadates Ca9 R(VO4)7. II. R = Tb, Dy, Ho, and Y

Crystal structures of the compounds Ca₉ R(VO₄)₇ (R = Tb (I), Dy (II), Ho (III), and Y (IV) have been studied by the method of the full-profile analysis. All the compounds are crystallized in the trigonal system (sp. gr. R 3 c, Z = 6) with the unit-cell parameters (I) a = 10.8592(1), c = 38.035(1), V = 3884.2(2) ų; (II) a = 10.8564(1), c = 38.009(1) Å, V = 3879.6(2) ų, (III) a = 10.8565(1) and c = 37.995(1) Å, V = 3878.3(2) ų, and (IV) a = 10.8588(1), c = 37.995(1) Å, V = 3879.9(2) ų. In structures I–IV, rare earth and calcium cations occupy three positions—M(1), M(2), and M(5). Rare earth cations occupy the R ³⁺ positions almost in the same way: 2.7–2.6(2) cations in the M(1) position; 2.7–2.3(2) cations in the M(2) position, and 0.6–1.0(1) cation in the M(5) position. At the same time, the occupancy of the M(5) position regularly increases with a decrease of the R ³⁺ radius.     

Structure and some properties of [UO<Subscript>2</Subscript>(C<Subscript>5</Subscript>H<Subscript>12</Subscript>N<Subscript>2</Subscript>O)<Subscript>5</Subscript>](ClO<Subscript>4</Subscript>)<Subscript>2</Subscript>

Compound [UO₂(C₅H₁₂N₂O)₅](ClO₄)₂ is synthesized and characterized by thermogravimetry, IR spectroscopy, and X-ray diffraction. The compound crystallizes in the monoclinic crystal system; a = 15.2985(9) Å, b = 26.9676(15) Å, c = 20.6962(11) Å, β = 100.697(1)°, space group P2₁/c, Z = 8, and R = 0.0445. Discrete [UO₂(C₅H₁₂N₂O)₅]²⁺ groups belonging to the AM ₅ ¹ crystal chemical group of uranyl complexes (A = UO ₂ ²⁺ and M ¹=C₅H₁₂N₂O) are uranium-containing structural units of the crystals.     

Structural characteristics of a new cation-deficient representative of the labuntsovite group

The crystal structure of a new representative of the labuntsovite group from the Khibiny massif (the Kola Peninsula) has been refined. The unit-cell parameters are a = 14.298(7) Å, b = 13.816(7) Å, c = 7.792(3) Å, β = 116.85(5)°, V = 1373.3 ų, sp. gr. C2/m, R^aniso = 0.047, 1084 reflections with F > 4σ (F). The mineral differs from lemmleinite-Ba and other members of the group by the predominance of the vacancies in two key cationic positions—C position is occupied by Ba cations (37%) and D position is occupied mainly by Mn cations (47%).     

Synthesis,Crystal Structure,and Free Radical Scavenging Activity of 4-Aminopyridinium 3,5-Dinitrobenzoate

The crystal structure of 4-aminopyridinium 3,5-dinitrobenzoate, C₁₂H₁₀O₆N₄, has been determined by single-crystal X-ray diffraction technique. The title compound crystallizes in the monoclinic sp. gr. P21/n with the unit cell parameters: a = 7.4726(3) Å, b = 23.0898(9) Å, c = 8.0744(4) Å, V = 1338.64(10) ų, Z = 4. The asymmetric unit of the compound consists of one 3,5-dinitrobenzoate anion and 4-aminopyridine cation. The adjacent anions and cations are linked through two N?H···O hydrogen bonds, N2?H2A···O5 and N₂?H2B···O6, to form an infinite chain of anions and cations, extended along the [010] direction.     

Crystal and molecular structures of complex between ammonium iodide monohydrate and the cis-syn-cis isomer of dicyclohexano-18-crown-6

The structure of the [(DCH-6A ? NH₄)(H₂O)I]₂ complex obtained by the reaction between the cis-syn-cisisomer of dicyclohexano-18-crown-6 (DCH-6A) and NH₄I has been determined by X-ray diffraction analysis. The crystals are triclinic, a = 9.314(3) Å, b = 11.951(2) Å, c = 12.040(1) Å, α = 77.36(1)°, β = 81.59(1)°, γ = 80.41(2)°, space group $P\bar 1$ , Z = 2, and the final R factor is 0.044. The structure is built up of the (DCH-6A ? NH₄) + cationic complexes, iodide anions, and water molecules. The ammonium ion forms three hydrogen bonds of the NH?O type [N?O, 2.881(5)–2.890(5) Å] with the oxygen atoms of the crown ether molecule. The organic cations are joined together into centrosymmetric dimers through the system of hydrogen bonds of the NH?OH type. The I^??O distances (where the O atom belongs to the bridging water molecule) fall in the range 3.558(4)–3.610(4) Å.     

X-ray diffraction study of Rb<Subscript>2</Subscript>[(UO<Subscript>2</Subscript>)<Subscript>2</Subscript>(CrO<Subscript>4</Subscript>)<Subscript>3</Subscript>(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>] · 4H<Subscript>2</Subscript>O

The compound Rb₂[(UO₂)₂(CrO₄)₃(H₂O)₂] · 4H₂O was studied by X-ray diffraction. The crystals are monoclinic, a = 10.695(2) Å, b = 14.684(3) Å, c = 14.125(3) Å, β = 108.396(4)°, sp. gr. P2₁/c, Z = 4, V = 2104.9(7) ų, and R = 0.0491. The main structural units are layers consisting of [(UO₂)₂(CrO₄)₃(H₂O)₂]^2? anions belonging to the crystal-chemical group A ₂ T ₂ ³ B ²M ₂ ¹ (A = UL ₂ ²⁺ , T ³ and B ² are CrO ₄ ^2? , and M ¹ is H₂O) of uranyl complexes. The uranium-containing layered groups are held together by electrostatic interactions with rubidium cations, as well as by hydrogen bonds with the participation of inner- and outer-sphere water molecules.     

Crystal structure of strontium hilgardite

The crystal structure of strontium hilgardite, CaSr[B₅O₉]Cl ? H₂O, was established by the method of X-ray diffraction analysis (synchrotron radiation; diffractometer equipped with a position-sensitive detector; λ = 0.688 Å; 3191 reflections with F < 4σ(F); R = 0.045 in the anisotropic approximation). The triclinic unit-cell parameters are as follows: a = 6.5732(6) Å, b = 6.4445(6) Å, c = 6.3693(6) Å, α = 60.995(2)°, β = 61.257(2)°, γ = 77.191(2)°, sp. gr. P1; Z = 1. The Ca and Sr atoms were found to be disordered over two positions. The structures of strontium hilgardite and hilgardite-1A differ in the configurations of the seven-vertex Sr-and Ca(2)-polyhedra. The structure solved in this work is consistent with two series of borates studied previously. One of these groups involves pentaborates with different degrees of hydration of borate complexes, and the second group includes Sr-containing borates.     

Crystal structure of strontium aqua(ethylenediaminetetraacetato)cobaltate(II) tetrahydrate Sr[CoEdta(H2O)] · 4H2O

The complex Sr[Co^II Edta] · 5H₂O (I) (where Edta ^4? is the ethylenediaminetetraacetate ion) has been synthesized. The crystal structure of this compound is determined by X-ray diffraction. Crystals are monoclinic, a = 7.906(2) Å, b = 12.768(2) Å, c = 18.254(3) Å, β = 95.30(3)°, V = 1834.8 ų, space group P2₁/n, Z = 4, and R = 0.036. The structure is built up of the binuclear complex fragments {Sr(H₂O)₃[CoEdta(H₂O)]}, which consist of the anionic [CoEdta(H₂O)]^2? and cationic [Sr(H₂O)₃]²⁺ units linked by the Sr-O bonds into a three-dimensional framework. The coordination polyhedra of the Co and Sr atoms are mono-and bicapped trigonal prisms. The coordination sphere of the Co atom (the coordination number is equal to 6 + 1) involves six donor atoms (2N and 4O) of the Edta ^4? ligand and the O_w atom of water molecule. One of the Co-O distances (2.718 Å) is considerably longer than the other Co-O_lig distances (2.092–2.190 Å) and the Co-O_w(1) distance (2.079 Å). The Sr coordination polyhedron (the coordination number is eight) contains three water molecules, three carbonyl O atoms of the three different anionic complexes, and two O atoms of one acetate group of the fourth anionic complex. The Sr-O distances fall in the range 2.535–2.674 Å. The structural formula of the compound is {Sr(H₂O)₃[CoEdta(H₂O)]}_3∞ · H₂O.     

Alkali metals in beryl and their role in the formation of derivative structural motifs: Comparative crystal chemistry of vorobyevite and pezzottaite

The crystal structures of high-alkali beryl, i.e., vorobyevite Cs_0.08Na_0.42(H₂O)_{0.18 + y} × [Al₂(Be_2.35Li_0.65)Si₆O₁₈], (a = 9.2102(14) Å, c = 9.2179(14) Å, space group P6/mcc, Z = 2, ρ_calcd= 2.74 g/cm³) and pezzottaite Cs_0.75Na_0.23(H₂O)_0.24[Al₂Be₂Li(Si₆O₁₈)] (a = 15.955(3) Å, c = 27.810(8) Å, space group, R $ \bar 3 The crystal structures of high-alkali beryl, i.e., vorobyevite Cs_0.08Na_0.42(H₂O)_{0.18 + y} × [Al₂(Be_2.35Li_0.65)Si₆O₁₈], (a = 9.2102(14) ?, c = 9.2179(14) ?, space group P6/mcc, Z = 2, ρ_calcd= 2.74 g/cm³) and pezzottaite Cs_0.75Na_0.23(H₂O)_0.24[Al₂Be₂Li(Si₆O₁₈)] (a = 15.955(3) ?, c = 27.810(8) ?, space group, R c, Z = 18, ρ_calcd= 3.13 g/cm³), are determined at a temperature of 100 K. It is confirmed that, at a high lithium content in minerals of the beryl group, lithium is selectively incorporated into Be tetrahedra. The positive charge deficit due to the replacement of Be²⁺ cations by Li⁺ cations is compensated by incorporating large alkali cations into the “zeolite” channel. It is shown that, when the lithium content becomes close to unity per the corresponding formula, the Li and Be atoms are ordered and the rhombohedral structure of pezzottaite is formed. It is proposed to retain the historical name vorobyevite for the lithium- and cesium-containing variety of beryl with a disordered distribution of Be and Li atoms. Original Russian Text ? O.V. Yakubovich, I.V. Pekov, I.M. Steele, W. Massa, N.V. Chukanov, 2009, published in Kristallografiya, 2009, Vol. 54, No. 3, pp. 432–445.     

Refinement of the crystal structure of calcioancylite-(Ce) by the Rietveld method

The crystal structure of calcioancylite-(Ce) of the (Ca_0.30Sr_0.22)_Σ0.52(Ce_0.78La_0.47Nd_0.16Pr_0.05Sm_0.02)_Σ1.48(CO₃)₂((OH)_1.20F_0.28)_Σ1.48 · 1.97H₂O composition from alkali hydrothermalites of Mont Saint-Hilaire, Canada, has been refined by the Rietveld method. The refinement details are as follows: ADP-2 diffractometer, λCuK _α radiation, Ni filter, 10.50° < 2θ < 140.00°, and the number of reflections (α₁ + α₂) 652. All calculations have been performed within the sp. gr. Pmcn (a = 5.0095(1) Å, b = 8.5006(1) Å, c = 7.2670(1) Å, V = 309.46(1) ų, R _wp = 3.45) in the anisotropic approximation of thermal vibrations for cations.