Ammonium-exchanged phase of γ-titanium phosphate

The monoammonium salt of γ-titanium phosphate has been prepared by hydrothermal treatment of π-Ti₂O(PO₄)₂·2H₂O in the presence of urea and phosphoric acid, and its crystal structure was obtained by Rietveld analysis using powder X-ray diffraction data. γ-Ti(PO₄)(NH₄HPO₄) crystallizes in the monoclinic space group P2₁/m with a = 5.0725(3) Å, b = 6.3101(3) Å, c = 11.2435(5) Å, β = 97.980(3)° (Z = 2). The structure consists of 2D titanium phosphate layers in the ab-plane. The titanium atoms and one of the phosphate groups are located nearly in the ab-plane of the layer. All the oxygen atoms of this phosphate group are involved in titanium coordination sphere. The other phosphate group located in the layers edges links two neighboring titanium atoms in the a-direction through two of its oxygen atoms. The remaining two oxygens are pointed toward the interlayer space being involved in hydrogen bond interactions with the ammonium ions. Each ammonium ion is shared by four oxygens belonging to four different phosphate hydroxyl groups. γ-Ti(PO₄)(NH₄HPO₄) is stable until 453 K, while above this temperature, it transforms to γ’-Ti(PO₄)(NH₄HPO₄) high temperature polymorph stable until 573 K. Thermal decomposition of this material leads to cubic TiP₂O₇ structure, with previous formation of two intermediate pseudo-layered compounds: Ti(PO₄)(NH₄HP₂O₇)_0.5 and Ti(PO₄)(H₂P₂O₇)_0.5. The activation energy of thermal decomposition has been calculated as a function of the extent of conversion applying the Kissinger–Akahira–Sunose (KAS) isoconversional method to the thermogravimetric data.     

Structural study of the NaCdVO4-Cd3V2O8 and CdO-V2O5 sections of the ternary system Na2O-CdO-V2O5

The NaCdVO₄-Cd₃V₂O₈ and CdO-V₂O₅ sections of the ternary system Na₂O-CdO-V₂O₅ have been studied and the crystal structures of Cd₃V₂O₈ and Cd₁₈V₈O₃₈ compounds were determined from single-crystal X-ray diffraction data. Cd₃V₂O₈ crystallizes with the maricite-type structure in space group Pnma, a=9.8133(10) Å, b=6.9882(10) Å, c=5.3251(10) Å and Z=4, whereas Cd₁₈V₈O₃₈ crystallizes in space group P1 with a new-type structure, a=8.5761(14), b=8.607(3), c=12.896(2) Å, α=95.64(1), β=102.45(1), γ=108.42(1)° and Z=1. The Cd₃V₂O₈ structure is made up of Cd1O₄ infinite chains of edge-sharing Cd1O₆ octahedra which are parallel to the b direction. The Cd1O₄ chains are linked together by VO₄ tetrahedra and strongly distorted Cd2O₄ tetrahedra. The structure of Cd₁₈V₈O₃₈ is based on an ordered three-dimensional framework of cadmium and vanadium polyhedra that share corners. The distorted CdO₆ octahedra, CdO₅ trigonal bipyramids and CdO₅ square pyramids share corners, edges or faces.     

Cu(I) cloride complexes with 4,5-(2-pyridylethylene)dithio-1,3-dithiol-2-thione and triphenylphosphine

Heteroligand binuclear complexes of CuCl with triphenylphosphine and 5-pyridine-2-yl-5,6-dihydro-[1,3]dithiolo[4,5-b][1,4]dithiine-2-thione (L¹) of the compositions [CuCl(PPh₃)(L¹)]₂ (I) and [CuCiL¹]₂ (II) are synthesized and studied by X-ray diffraction method. Crystals I are monoclinic; space group P2₁/n, a=8.9520(18) Å, b=18.926(4) Å, c=16.841(3) Å, β=94.96(3)°, Z=2. The Cu(I) atom has a quasi-tetrahedral surrounding involving the tetraphenylphosphine P atom, the pyridyl N atom of the molecule L¹, and two bridging Cl atoms. Crystals II are monoclinic; space group P2₁/c, a=9.3520(19) Å, b=8.1490(16) Å, c=18.660(4) A, β = 104.43(3)°, Z = 2. Both L¹ ligands in complex II act as bridges. The Cu(I) atom also has a quasi-tetrahedral surrounding formed by the Cl atoms, the pyridyl N atoms and thiol S atom of one L¹ ligand, and the thione S atom of the second L¹ ligand. Similar binuclear complexes with the bridging function of the L¹ ligand were also detected in a solution of II by the ESI method.     

Identification of a new family of phosphate compounds,AIBII6(P2O7)2P3O10: structures of KMn6(P2O7)2P3O10 and AgMn6(P2O7)2P3O10

Two members of a new family of inorganic phosphates of general formula A^IB^II₆(P₂O₇)₂P₃O₁₀; KMn₆(P₂O₇)₂P₃O₁₀ (a=5.405(2), b=26.918(11), c=6.660(5), β=107.31(3)°, V=925.1(9) Å³, space group P2₁/m, Z=2, D_calc=3.481 Mg m⁻³, R=0.0377 for 2235 observed reflections) and AgMn₆(P₂O₇)₂P₃O₁₀ (a=5.424(7), b=26.97(4), c=6.627(9), β=106.81(7)°, V=928(2) Å³, space group P2₁/m, Z=2, D_calc=3.716 Mg m⁻³, R=0.0594 for 1577 observed reflections) have been synthesized and identified by single crystal X-ray diffraction. The isostructural complexes present an interesting comparison of silver and potassium bonding.     

Crystal structure of BiNbTe2O8

BiNbTe₂O₈ crystallises with orthorhombic symmetry (space group Pbca) and unit cell parameters: a=5.6109(7) Å, b=8.1277 (8) Å, c=31.205 (3) Å, Z=8. Its crystal structure has been solved from single crystal X-ray diffraction data and refined to a final reliability factor R1=0.0512. It can be described as a regular succession along [001] of ReO₃-like sheets of NbO₆ octahedra, and fluorite-like sheets of BiO₈ distorted cubes and Te(1)O₄ disphenoı̈ds. These sheets are connected by Te(2)O₃ pyramids via Nb–O(4)–Te(2)–O(8)–Bi bridges. The lone pairs of Te(1) and Te(2) atoms are stereochemically active and point toward the empty cuboctahedral sites of the ReO₃-like sheets.     

Crystal structure and ionic conductivity of AgCr2(PO4)(P2O7)

Single crystals of a new phosphate AgCr₂(PO₄)(P₂O₇) have been prepared by the flux method and its structural and the infrared spectrum have been investigated. This compound crystallizes in the monoclinic system with the space group C2/c and the parameters are, a = 11.493 (3) Å, b = 8.486 (3) Å, c = 8.791 (2) Å, β = 114.56 (2)°, V = 779.8 (3) ųand Z = 4. Its structure consists of CrO₆ octahedra sharing corners with P₂O₇ units to form undulating chains extending infinitely along the [110] direction. These chains are connected by the phosphate tetrahedra giving rise to a 3D framework with six-sided tunnels parallel to the [101] direction, where the Ag⁺ ions are located. The infrared spectrum of this compound was interpreted on the basis of P₂O₇^4? and PO₄^3? vibrations. The appearance of ν_sP–O–P in the spectrum suggests a bent P–O–P bridge for the P₂O₇^4? ions in the compound, which is in agreement with the X-ray data. The electrical measurements allow us to obtain the activation energy of (1.36 eV) and the conductivity measurements suggest that the charge carriers through the structure are the silver captions.     

Structures of bis(2-thiobarbiturato-O)tetraaquamagnesium and catena-[(μ2-2-thiobarbiturato-O,O)(2-thiobarbiturato-O) bis(μ2-aqua)diaquastrontium] monohydrate

The crystal structures of bis(2-thiobarbiturato-O)tetraaquamagnesium Mg(H₂O)₄(HTBA-O)₂ I and catena-[(μ₂-2-thiobarbiturato-O,O)(2-thiobarbiturato-O)bis(μ₂-aqua)diaquastrontium] monohydrate catena-[Sr(μ₂-H₂O)₂(H₂O)₂(μ₂-HTBA-O,O)(HBTA-O)] _n · nH₂O (II), where H₂TBA is 2-thiobarbituric acid C₄H₄N₂O₂S, have been determined. Crystal data for a=6.7598(2) Å, b = 7.6060(2) Å, c = 8.5797(2) Å, α = 79.822(2)°, β = 76.622(1)°, γ = 69.124(1)°, V = 398.82(2) ų, space group P $\bar 1$ , Z = 1; for II: a = 20.8499(4) Å, b = 19.2649(5) Å, c = 4.14007(9) Å, β = 92.023(2)°, V = 1661.91(7) ų, space group P2₁/n, Z = 4. The Mg²⁺ ion in I is bonded to six O atoms of two HTBA^? ions and four water molecules that form a nearly regular octahedron. Each Sr²⁺ ion in II is coordinated to three oxygen atoms of three HTBA^? ions and six water molecules that form an almost ideal tricapped trigonal prism. These polyhedra share edges to form infinite chains. Intermolecular hydrogen bonds create layered structures of I and II.     

Structural chemistry of Ba2CdS3, Ba2CdSe3, BaCdS2, BaCu2S2 and BaCu2Se2

The structures of all compounds were determined from three dimensional single crystal X-ray diffraction data and refined by least squares. Ba₂CdS₃ and Ba₂CdSe₃ are isostructural, Pnma, a = 8.9145(6)Å, b = 4.3356(2)Å, c = 17.2439(9)Å for the former compound and a = 9.2247Å, b = 4,4823(6)Å, c = 17.8706(11)Å for the latter, z = 4, R = 0.0751 and R = 0.0462, respectively. The compounds are isostructural with the previously reported Mn analogues and with K₂AgI₃. Cd ions are in tetrahedral environment and the tetrahedra form infinite linear chains by corner sharing. Ba ions are in 7-fold coordination in which 6 anions form a trigonal prism and 1 anion caps one of the rectangular faces. BaCdS₂, Pnma, a = 7.2781(3)Å, b = 4.1670(1)Å, c = 13.9189(6)Å, z = 4, R = 0.0685. Cd ions can be considered to have a triangular planar coordination with CdS distances of 2.47 and 2.53 Å (twice). Two additional S ions are at 2.89 and 3.22 Å to complete a triangular bipyramidal configuration. Ba is in 7-fold coordination with the anions forming a trigonal prism which is capped on one rectangular face. The compound is isostructural with BaCdO₂ and is related to the structure of BaMnS₂. BaCdSe₂ could not be prepared. BaCu₂S₂ and BaCu₂Se₂ are isostructural, Pnma, a = 9.3081(4)Å, b = 4.0612(3)Å, c = 10.4084(5)Å for the sulfide and a = 9.5944(6)Å, b = 4.2142(4)Å, c = 10.7748(8)Å for the selenide, z = 4, R = 0.0634 and 0.0373, respectively. Ba ions are in the usual 7-fold, capped hexagonal prism, coordination. However, 9 Cu ions also can be considered to form a trigonal prism with all rectangular faces capped, around Ba since the BaCu distances range from 3.24 to 3.54 Å for the sulfide and from 3.37 to 3.67 Å for the selenide. One of the Cu ions is in a very distorted tetrahedral environment and the second one is located in a more regular tetrahedral configuration of the anions. Two independent infinite chains of tetrahedra are present. They are formed by sharing of two adjacent edges of each tetrahedron and then these chains in turn are linked by corner sharing into a three-dimensional network of tetrahedra.     

Ba2(VO2)(PO4)(HPO4)·H2O, a New Barium Vanadium(V) Phosphate Hydrate Containing Trigonal Bipyramidal VO5Groups

The hydrothermal synthesis, single crystal structure, and some physical properties of Ba₂(VO₂)(PO₄)(HPO₄)·H₂O, a new barium vanadium(V) phosphate hydrate, are reported. This phase is built up from one-dimensional chains of unusual VO₅trigonal bipyramids and (H)PO₄tetrahedra, fused together via V–O–P linkages. These anionic chains propagate along the polar [010] direction. 11-Coordinate barium cations and water molecules occupy the interchain regions and link the chains together. Structural data for this phase and other known barium vanadium phosphates are briefly compared. Crystal data: Ba₂(VO₂)(PO₄)(HPO₄)·H₂O,M_r=566.57, monoclinic, space groupP2₁(No. 4),a=5.0772(5) Å,b=8.724(2) Å,c=10.806(1) Å,β=90.795(8)°,V=478.6(1) ų,Z=2,R=2.65%,R_w=2.89% [147 parameters, 1893 observed reflections withI>3σ(I)].     

Single crystal growth and structural characterization of ternary transition-metal uranium oxides: MnUO4, FeUO4, and NiU2O6

Single crystals of MnUO₄, FeUO₄, and NiU₂O₆ were grown for the first time. The use of chloride fluxes facilitated the crystal growth. MnUO₄, a hexavalent uranium compound, crystallizes in the orthorhombic space group, Imma, with a = 6.6421(19) Å, b = 6.978(2) Å, and c = 6.748(2) Å, and exhibits typical uranyl, UO₂²⁺, coordination. FeUO₄ and NiU₂O₆ contain pentavalent uranium and are structurally related, exhibiting three-dimensional connectivity. FeUO₄ crystallizes in the orthorhombic space group, Pbcn, with a = 4.8844(2) Å, b = 11.9328(5) Å, c = 5.1070(2) Å. NiU₂O₆ crystallizes in the trigonal space group, P321, with a = 9.0148(3) Å, c = 5.0144(3) Å.     

Synthesis, characterization, and structure determination of the orthorhombic U2(PO4)(P3O10)

β-UP₂O₇ has been synthesized under hydrothermal conditions (θ=500°C, P=200 MPa), using UO₂ and H₃PO₄. β-UP₂O₇ crystallizes in the orthorhombic space group Pn2₁a, with a=11.526 (2) Å, b=7.048 (2) Å, c=12.807 (2) Å and Z=4. Its structure has been determined through direct methods and difference Fourier synthesis and has been refined to R=0.0396. The structure is built on UO₈ polyhedral chains along the b-axis. PO₄³⁻ and P₃O₁₀⁵⁻ groups coexist in the structure and the latter groups form non-linear chains. Cohesion of the structure is made through the linkage of UO₈ chains by PO₄ and P₃O₁₀ groups leading to the formula U₂(PO₄)(P₃O₁₀) instead of β-UP₂O₇. Vibrational and optical spectra confirm the results obtained by X-ray diffraction. DTA-TGA measurements show that the transformation of U₂(PO₄)(P₃O₁₀) to the cubic α-UP₂O₇ occurs at θ=870°C.     

Crystal structure of neodymium and gadolinium dihydroxy-nitrate,Ln(OH)2NO3

The crystal structures of Nd(OH)₂NO₃ and Gd(OH)₂NO₃ have been determined from single-crystal X-ray diffraction techniques. Crystallization occurs in monoclinic space group P2₁ (No. 4) with a = 6.420(1), b = 3.838(1), c = 7.746(2) Å, and β = 98.18(2)° for Nd(OH)₂NO₃ and a = 6.340(2), b = 3.715(1), c = 7.728(2) Å, and β = 96.95(2)° for Gd(OH)₂NO₃. The structures were refined to residual indices of 0.025 and 0.048, respectively, using 372 and 360 unique reflections. The lanthanoid metal atoms are nine-coordinated, having a tricapped trigonal prismatic geometry. The nitrate counter ion acts as a bidentate ligand, while the two hydroxide oxygen atoms link symmetry-related lanthanoid atoms, forming two-dimensional layers.     

Crystal structure,physical properties and bond valence analysis of NaLuP2O7

Single crystals of a diphosphate NaLuP₂O₇ have been synthesized by the flux method and characterized by single-crystal X-Ray diffraction. NaLuP₂O₇ crystallizes in the monoclinic system with P2₁/n space group with cell parameters: a = 8.9985(8) Å, b = 5.3473(5) Å, c = 12.756(1) Å, β = 103.174° (1), V = 597.67 (9) Å³, Z = 4. Its structure consists of a three-dimensional framework of P₂O₇ units that are corner-shared by LuO₆ octahedra, forming tunnels running parallel to [010] which are occupied by Na atoms. NaLuP₂O₇ powder was characterized by XRD, SEM, FTIR and Raman spectroscopy. The activation energy of (1.49 eV) obtained by electrical measurements suggests the charge carriers to be the sodium cations. The activation energies obtained from impedance and loss spectra were analyzed in order to explain the mechanism of conduction. The correlation between ionic conductivity of NaLuP₂O₇ and its crystallographic structure was investigated and the most probable transport pathway model was determined.     

Hydrothermal Synthesis, Crystal Structure and Properties of a New Porous Zinc Arsenite Zn3As2O6 with the Novel Helical Zn–O Chains

A new porous zinc arsenite Zn₃As₂O₆ 1 has been synthesized under hydrothermal conditions, and characterized by X-ray single crystal diffraction, IR and TG analysis. The structural analysis reveals that compound 1 is constructed from a network of AsO₃ trigonal pyramids and ZnO₄ tetrahedra, and represents a 3D framework with one-dimensional 8-membered-ring channels and interesting helical Zn–O chains. Crystal data for 1: Monoclinic, space group P2(1)/c, a = 8.250(4) Å, b = 5.186(3) Å, c = 15.824(9) Å, β = 97.379(9)°, V = 671.4(6) Å³, Z = 4, R1 = 0.0481, and wR2 = 0.0834.     

Solvothermal synthesis and crystal structure of the Mo(VI)-bridged helical chain containing Mo2(V) dimers: (C4H12N2)2[(MoV2O4)(MoVIO4)(C2O4)2]·2H2O

A new molybdenum complex (C₄H₁₂N₂)₂[(Mo^V₂O₄)(Mo^VIO₄)(C₂O₄)₂]·2H₂O, was solvothermally synthesized and characterized by single-crystal X-ray diffraction. The structure of the compound consists of oxalate acid-coordinated mixed-valent [Mo^V₂O₄][Mo^VIO₄] helical chains and protonated piperazine cations. The helical chains are built up from the [Mo^V₂O₄] units and [Mo^VIO₄] tetrahedral. The central axis about helical chain is a 2-fold screw axis. The compound crystallizes in the space group P2₁/n of monoclinic system with a = 11.396(2) Å, b = 14.107(3) Å, c = 15.805(3) Å, β = 102.09(3)°, V = 2484.6(9) Å³, Z = 4. Other characterizations by elemental analysis, IR, and thermal analysis for this compound are also given.     

Crystal structure of catena-(2-thiobarbiturato) dithallium(I)

By powder X-ray diffraction the crystal structure of catena-(2-thiobarbiturato)dithallium(I) C₄H₂N₂O₂STl₂ (C₄H₄N₂O₂S is 2-thiobarbituric acid, H₂TBA), Tl₂TBA, is determined. Crystallographic data for Tl₂TBA are as follows: a = 15.1039(3) Å, b = 12.0818(2) Å, c = 3.86455(6) Å, β = 97.203(1)°, V = 741.34(2) ų, space group P2₁/n, Z = 4. There are two non-equivalent thallium atoms in the structure. The Tl1 polyhedron is a distorted trigonal prism due to the shortened Tl-S contact (3.634 Å), and the Tl2 polyhedron is a distorted square antiprism.     

Redox reaction on treating fac- or mer- [Mo(CO)3(dppm-PP')(dppm-P)] (dppm = Ph2PCH2PPh2) with Hg(SCN)2 and crystal structure of the seven-coordinate product [Mo(CO)2(NCS)2(dppm-PP')(dppm-P)]

[Mo(CO)₂(NCS)₂(dppm-PP')(dppm-P)] (dppm = Ph₂PCH₂PPh₂) is formed in a rapid and clean redox reaction when fac- or mer-[Mo(CO)₃(dppm-PP')(dppm-P)] is treated with Hg(SCN)₂: dppm-chelate ring-opening with formation of a heterobimetallic species is not observed. The X-ray crystal structure of the product shows the molecule to contain seven-coordinate Mo(II) with “cis” CO groups, both monodentate and chelating dppm ligands, and with N-bonded NCS groups. The coordination geometry is intermediate between a capped trigonal prism and a capped octahedron. Crystals of [Mo(CO)₂ (NCS)₂(dppm-PP')(dppm-P)] are orthorhombic, space group Pna2₁, with a = 21.583(7) Å, b = 12.775(4) Å, c = 18.484(5) Å, and Z = 4; the final R factor was 0.046 for 3181 observed reflections.     

New gallium pentaphosphates: AGa2P5O16 (A=Rb,Cs)

Gallium pentaphosphates have been synthesized for the first time. These compounds, RbGa₂P₅O₁₆ and CsGa₂P₅O₁₆, are isotypic to the cesium pentaphosphates CsM₂P₅O₁₆ (M=Fe, V). They crystallize in the noncentrosymmetric Pn space group with a=7.4058(3) Å, b=9.2151(2) Å, c=10.0912(11) Å, β=110.768(8)°, V=643.9(1) Å³ (Z=2) and a=7.462(2) Å, b=9.241(3) Å, c=10.103(2) Å, β=110.731(16)°, V=651.5(3) Å³ (Z=2) for the rubidium and cesium compounds, respectively. The single crystal structure determination shows that the 3D [Ga₂P₅O₁₆]_∞ framework is rather rigid and does not vary significantly whatever M=Fe, V, Ga and A=Rb, Cs. The strongly distorted character of the pentaphosphate unit may be at the origin of strains along the P₅O₁₆ group, which explains the difficulty to stabilize pentaphosphates.     

Two Novel CuII Phenanthroline Adipato Complexes with π‐π Stacking Interactions: [Cu(phen)2(C6H8O4)] · 4.5 H2O and [(Cu2(phen)2Cl2)(C6H8O4)] · 4 H2O

The blue copper complex compounds [Cu(phen)₂(C₆H₈O₄)] · 4.5 H₂O ( 1 ) and [(Cu₂(phen)₂Cl₂)(C₆H₈O₄)] · 4 H₂O ( 2 ) were synthesized from CuCl₂, 1,10‐phenanthroline (phen) and adipic acid in CH₃OH/H₂O solutions. [Cu(phen)₂‐ (C₆H₈O₄)] complexes and hydrogen bonded H₂O molecules form the crystal structure of ( 1 ) (P1 (no. 2), a = 10.086(2) Å, b = 11.470(2) Å, c = 16.523(3) Å, α = 99.80(1)°, β = 115.13(1)°, γ = 115.13(1)°, V = 1617.5(5) ų, Z = 2). The Cu atoms are square‐pyramidally coordinated by four N atoms of the phen ligands and one O atom of the adipate anion (d(Cu–O) = 1.989 Å, d(Cu–N) = 2.032–2.040 Å, axial d(Cu–N) = 2.235 Å). π‐π stacking interactions between phen ligands are responsible for the formation of supramolecular assemblies of [Cu(phen)₂(C₆H₈O₄)] complex molecules into 1 D chains along [111]. The crystal structure of ( 2 ) shows polymeric [(Cu₂(phen)₂Cl₂)(C₆H₈O₄)_2/2] chains (P1 (no. 2), a = 7.013(1) Å, b = 10.376(1) Å, c = 11.372(3) Å, α = 73.64(1)°, β = 78.15(2)°, γ = 81.44(1)°, V = 773.5(2) ų, Z = 1). The Cu atoms are fivefold coordinated by two Cl atoms, two N atoms of phen ligands and one O atom of the adipate anion, forming [CuCl₂N₂O] square pyramids with an axial Cl atom (d(Cu–O) = 1.958 Å, d(Cu–N) = 2.017–2.033 Å, d(Cu–Cl) = 2.281 Å; axial d(Cu–Cl) = 2.724 Å). Two square pyramids are condensed via the common Cl–Cl edge to centrosymmetric [Cu₂Cl₂N₄O₂] dimers, which are connected via the adipate anions to form the [(Cu₂(phen)₂Cl₂)(C₆H₈O₄)_2/2] chains. The supramolecular 3 D network results from π‐π stacking interactions between the chains. H₂O molecules are located in tunnels.     

Crystal structure and triboluminescence of the [Eu(TTA)2(NO3)(TPPO)2] complex

The crystal structure of [Eu(TTA)₂(NO₃)(TPPO)₂] (I) (TTA = thenoyltrifluoroacetone, TPPO = triphenylphosphine oxide) possessing intense triboluminescence was established by X-ray crystallography. The crystals are triclinic, noncentrocymmetrical: a = 11.047(3) Å, b = 11.794(3) Å, c = 12.537(3) Å; α = 102.635 (4)°, β = 102.088(4)°,γ = 117.765(3)°; space group P1, Z = 1. The central Eu(III) atom coordinates two oxygen atoms of two TPPO molecules at distances of 2.271 Å and 2.282 Å, two oxygen atoms of the nitrate group at distances of 2.478 Å and 2.481 Å, four oxygen atoms of two TTA ions at distances of 2.365 Å, 2.381 Å, and 2.363 Å, 2.371 Å (coordination number is 8). The coordination polyhedron of the Eu(III) atom is a distorted dodecahedron. Possible reasons for spectral differences in the Stark structure of photo-and triboluminescence of I are discussed.