Complex Borides RERu4B4 (RE = Ce,Pr, Nd,Sm) – Bonding Peculiarities and Magnetic Properties

The rare earth borides RERu₄B₄ (RE = Ce, Pr, Nd, Sm) were synthesized from the elements by arc‐melting and their crystal structures were studied on the basis of X‐ray powder and single‐crystal diffraction: LuRu₄B₄ type, I4₁/acd, a = 747.47(8), c = 1506.4(3) pm, wR₂ = 0.0579, 362 F² values for CeRu₄B₄, a = 751.3(2), c = 1507.1(5) pm, wR₂ = 0.0724, 471 F² values for PrRu₄B₄, a = 751.0(2), c = 1506.9(6) pm, wR₂ = 0.0598, 384 F² values for NdRu₄B₄, and a = 749.1(1), c = 1506.0(3) pm, wR₂ = 0.0759, 413 F² values for SmRu₄B₄, with 18 variables per refinement. Striking structural motifs of the RERu₄B₄ structures are Ru₄ tetrahedra and B₂ dumbbells with Ru–Ru and B–B distances of 271 and 180 pm in CeRu₄B₄. The intermediate valence of cerium leads to shorter Ce–Ru distances of 292 pm. CeRu₄B₄ behaves like a Pauli paramagnet with a small room temperature susceptibility of 1.5 × 10^–4 emu · mol^–1. Chemical bonding analyses shows substantial Ru–B and B–B bonding within the [Ru₄B₄] substructure.     

Dimorphic ErAgSn and TmAgSn – High‐Pressure and High‐Temperature Driven Phase Transitions

The stannides ErAgSn and TmAgSn have been investigated under high‐temperature (HT) and high‐pressure (HP) conditions in order to investigate their structural chemistry. ErAgSn and TmAgSn are dimorphic: normal‐pressure (NP) ErAgSn and HT‐TmAgSn crystallize into the NdPtSb type structure, P6₃mc, a = 466.3(1), c = 729.0(2) pm for NP‐ErAgSn and a = 465.4(1), c = 726.6(2) pm for HT‐TmAgSn. NP‐ErAgSn was obtained via arc‐melting of the elements and subsequent annealing at 970 K, while HT‐TmAgSn crystallized directly from the melt by rapidly quenching the arc‐melted sample. HT‐TmAgSn transforms to the ZrNiAl type low‐temperature modification upon annealing at 970 K. The high‐pressure (HP) modification of ErAgSn was synthesized under multianvil high‐pressure (11.5 GPa) high‐temperature (1420 K) conditions from NP‐ErAgSn: ZrNiAl type, , a = 728.7(2), c = 445.6(1) pm. The silver and tin atoms in NP‐ErAgSn and HT‐TmAgSn build up two‐dimensional, puckered [Ag₃Sn₃] networks (277 pm intralayer Ag–Sn distance in NP‐ErAgSn) that are charge‐balanced and separated by the erbium and thulium atoms. The fourth neighbor in the adjacent layer has a longer Ag–Sn distance of 298 pm. The [AgSn] network in HP‐ErAgSn is three‐dimensional. Each silver atom has four tin neighbors (281–285 pm Ag–Sn). The [AgSn] network leaves distorted hexagonal channels, which are filled with the erbium atoms. The crystal chemistry of the three phases is discussed.     

Syntheses and Crystal Structures of the Cyclotriphosphate Hydrates Nd(P3O9)·3H2O,Nd(P3O9)·4.5H2O,RE(P3O9)·5H2O (RE = Pr,Nd), and Na3RE(P3O9)2·6H2O (RE = Pr,Nd)

Several rare‐earth cyclotriphosphate hydrates were obtained from mixtures of sodium cyclotriphosphates and the respective rare‐earth chlorides. Nd(P₃O₉) · 3H₂O [P$\bar{6}$ , Z = 3, a = 677.90(9), c = 608.67(9) pm, R₁ = 0.016, wR₂ = 0.038, 312 data, 36 parameters] was obtained by a solid state reaction and is isotypic with respective rare‐earth phosphate hydrates, while all the others adopt new structure types. Nd(P₃O₉) · 4.5H₂O [C2/c, Z = 8, a = 1644.6(3), b = 756.11(15), c = 1856.1(4) pm, β = 97.25(3)°, R₁ = 0.032, wR₂ = 0.081, 1763 data, 194 parameters], Nd(P₃O₉) · 5H₂O [P2₁/c, Z = 4, a = 773.75(15), b = 1149.1(2), c = 1394.9(3) pm, β = 106.07(3)°, R₁ = 0.042, wR₂ = 0.082, 1338 data, 194 parameters], Pr(P₃O₉) · 5H₂O [P$\bar{1}$ , Z = 2, a = 745.64(15), b = 889.07(18), c = 934.55(19) pm, α = 79.00(3), β = 80.25(3), γ = 66.48(3), R₁ = 0.059, wR2 = 0.089, 1468 data, 193 parameters], Na₃Nd(P₃O₉)₂ · 6H₂O [P2₁/n, Z = 4, a = 1059.78(18), b = 1207.25(15), c = 1645.7(4) pm, β = 99.742(17), R₁ = 0.047, wR₂ = 0.119, 1109 data, 351 parameters] and Na₃Pr(P₃O₉)₂ · 6H₂O [P2₁/n, Z = 4, a = 1061.42(16), b = 1209.0(2), c = 1635.5(3) pm, β = 99.841(13), R₁ = 0.035, wR₂ = 0.062, 1323 data, 350 parameters] were obtained by careful crystallization at room temperature. A thorough structure discussion is given. The infrared spectrum of Nd(P₃O₉) · 4.5H₂O is also reported.     

New Rare‐Earth Metal Germanides RE2Ge9 (RE = Nd,Sm) by Thermal Decomposition of High‐Pressure Phases REGe5

The rare‐earth metal germanides RE₂Ge₉ (RE = Nd, Sm) have been prepared by thermal decomposition of the metastable high‐pressure phases REGe₅ at ambient pressure. The compounds adopt an orthorhombic unit cell with a = 396.34(4) pm; b = 954.05(8) pm and c = 1238.4(1) pm for Nd₂Ge₉ and a = 395.46(7) pm; b = 946.4(2) pm and c = 1232.1(3) pm for Sm₂Ge₉. Crystal structure refinements reveal space group Pmmn (No. 59) for Nd₂Ge₉. The atomic pattern resembles an ordered defect variety of the pentagermanide motif REGe₅ (RE = La; Nd, Sm, Gd, Tb) comprising corrugated germanium layers. These condense into a three‐dimensional network interconnected by eight‐coordinated germanium atoms. The resulting framework channels along [100] enclose the neodymium atoms. With respect to the atomic arrangement of the pentagermanides, half of the interlayer germanium atoms are eliminated in an ordered way so that occupied and empty germanium columns alternate along [001]. The rare‐earth metal atoms of both types of compounds, REGe₅ and RE₂Ge₉, exhibit the electronic states 4f ³ and 4f ⁵ (oxidation state +3) for neodymium and samarium, respectively, evidencing that the modification of the germanium network leaves the electron configuration of the metal atoms unaffected.     

High‐Pressure Synthesis and Single‐Crystal Structure Elucidation of the Indium Oxide‐Borate In4O2B2O7

The indium oxide‐borate In₄O₂B₂O₇ was synthesized under high‐pressure/high‐temperature conditions at 12.5 GPa/1420 K using a Walker‐type multianvil apparatus. Single‐crystal X‐ray structure elucidation showed edge‐sharing OIn₄ tetrahedra and B₂O₇ units building up the oxide‐borate. It crystallizes with Z = 8 in the monoclinic space group P2₁/n (no. 14) with a = 1016.54(3), b = 964.55(3), c = 1382.66(4) pm, and β = 109.7(1)°. The compound was also characterized by powder X‐ray diffraction and vibrational spectroscopy.     

Rare‐Earth‐Rich Magnesium Compounds RE23Rh7Mg4 (RE = La,Ce, Pr,Nd, Sm,Gd) with Tetrahedral Mg4 Clusters

The rare earth‐rich compounds RE₂₃Rh₇Mg₄ (RE = La, Ce, Pr, Nd, Sm, Gd) were prepared by induction‐melting the elements in sealed tantalum tubes. The new compounds were characterized by X‐ray powder diffraction. They crystallize with the hexagonal Pr₂₃Ir₇Mg₄ type structure, space group P6₃mc. The structures of La₂₃Rh₇Mg₄ (a = 1019.1(1), c = 2303.7(4) pm, wR2 = 0.0827, 1979 F² values, 69 variables), Nd₂₃Rh₇Mg₄ (a = 995.4(2), c = 2242.3(5) pm, wR2 = 0.0592, 2555 F² values, 74 variables) and Gd₂₃Rh_6.86(5)Mg₄ (a = 980.5(2), c = 2205.9(5) pm, wR2 = 0.0390, 2083 F² values, 71 variables) were refined from single crystal X‐ray diffractometer data. The three crystallographically different rhodium atoms have trigonal prismatic rare earth coordination with short RE–Rh distances (283–300 pm in Nd₂₃Rh₇Mg₄). The prisms are condensed via common edges, leading to a rigid three‐dimensional network in which isolated Mg₄ tetrahedra (312–317 pm Mg–Mg in Nd₂₃Rh₇Mg₄) are embedded. Temperature dependent magnetic susceptibility data of Ce₂₃Rh₇Mg₄ indicate Curie‐Weiss behavior with an experimental magnetic moment of 2.52(1) μ_B/Ce atom, indicative for stable trivalent cerium. Antiferromagnetic ordering is evident at 2.9 K.     

Crystal Structure Investigation of RE–Ni–Zn Ternary Compounds (RE = La,Ce, Tb)

The RENiZn (RE = La, Tb), RE₂Ni₂Zn (RE = La, Ce, Tb) and La₃Ni₃Zn ternary compounds were synthesized by two methods: by heating in a resistance furnace evacuated quartz ampoules containing Al₂O₃‐crucibles with element pieces and by induction melting in sealed Ta crucibles with subsequent annealing at 400 °C. Scanning electron microscopy (SEM) coupled with energy dispersive X‐ray spectroscopy (EDXS) was used for examining microstructure and phase composition of some of the alloys. The crystal structures for all the investigated phases were solved or confirmed on single crystal data by applying the direct methods refined by a standard least square procedure: LaNiZn – str. type ZrNiAl, hexagonal, , hP9, a = 0.7285(1), c = 0.3938(1) nm, wR₂ = 0.0534, 257 F² values, 14 variables; a = 0.7044(1), c = 0.3782(1) nm, wR₂ = 0.0447, 236 F² values, 14 variables for TbNiZn; La₂Ni₂Zn – str. type Pr₂Ni₂Al, orthorhombic, Immm, oI10, a = 0.4381(1), b = 0.5459(1) c = 0.8605(2) nm, wR₂ = 0.0824, 223 F² values, 13 variables; a = 0.4365(1), b = 0.5430(1) c = 0.8279(2) nm, wR₂ = 0.0635, 209 F² values, 13 variables for Ce₂Ni₂Zn; a = 0.4209(1), b = 0.5366(1) c = 0.8165 (1) nm, wR₂ = 0.0757, 200 F² values, 13 variables for Tb₂Ni₂Zn; La₃Ni₃Zn – str. type Y₃Co₃Ga, orthorhombic, Cmcm, oS28, a = 0.4276(1), b = 1.0310(2) c = 1.3636(3) nm, wR₂ = 0.0859, 579 F² values, 26 variables. The structural peculiarities of these compounds and their relations are discussed.     

Thermal,Magnetic, Electronic,and Superconducting Properties of Rare‐Earth Metal Pentagermanides REGe5 (RE = La,Nd, Sm,Gd) and Synthesis of TbGe5

A series of isotypic rare‐earth metal pentagermanides including the new compound TbGe₅ were prepared by high‐pressure synthesis. They crystallize in the orthorhombic space group Immm [No. 71; a = 395.70(9) pm; b = 611.1(2) pm, and c = 983.6(3) pm for TbGe₅]. The crystal structure is isotypic to LaGe₅ and consists of puckered germanium slabs, which sandwich a second germanium species and the rare‐earth metal atoms. At ambient pressure, the thermal decomposition of the phases REGe₅ (RE = La, Nd, Sm, Gd, and Tb) proceeds via discrete intermediate steps into Ge(cF8) and thermodynamically stable germanium‐poorer phases. The investigated compounds REGe₅ are paramagnetic metallic conductors, which order antiferromagnetically at low temperatures. Specific heat measurements reveal that the superconducting state of LaGe₅ below T_c = 7.1(1) K is characterized by a critical field of μ₀H_c2 = 0.2 T and weak electron‐phonon coupling. Density‐functional based band‐structure calculations yield a very similar electronic structure for all the isotypic REGe₅ compounds. Besides a slight increase in the width of the valence band for smaller RE atoms, only minor differences are found for the two different germanium environments.     

Synthesis and structure determination of seven ternary bismuthides: crystal chemistry of the RELi3Bi2 family (RE = La–Nd,Sm, Gd,and Tb)

Zintl phases are renowned for their diverse crystal structures with rich structural chemistry and have recently exhibited some remarkable heat‐ and charge‐transport properties. The ternary bismuthides RELi₃Bi₂ (RE = La–Nd, Sm, Gd, and Tb) (namely, lanthanum trilithium dibismuthide, LaLi₃Bi₂, cerium trilithium dibismuthide, CeLi₃Bi₂, praseodymium trilithium dibismuthide, PrLi₃Bi₂, neodymium trilithium dibismuthide, NdLi₃Bi₂, samarium trilithium dibismuthide, SmLi₃Bi₂, gadolinium trilithium dibismuthide, GdLi₃Bi₂, and terbium trilithium dibismuthide, TbLi₃Bi₂) were synthesized by high‐temperature reactions of the elements in sealed Nb ampoules. Single‐crystal X‐ray diffraction analysis shows that all seven compounds are isostructural and crystallize in the LaLi₃Sb₂ type structure in the trigonal space group Pm1 (Pearson symbol hP6). The unit‐cell volumes decrease monotonically on moving from the La to the Tb compound, owing to the lanthanide contraction. The structure features a rare‐earth metal atom and one Li atom in a nearly perfect octahedral coordination by six Bi atoms. The second crystallographically unique Li atom is surrounded by four Bi atoms in a slightly distorted tetrahedral geometry. The atomic arrangements are best described as layered structures consisting of two‐dimensional layers of fused LiBi₄ tetrahedra and LiBi₆ octahedra, separated by rare‐earth metal cations. As such, these compounds are expected to be valance‐precise semiconductors, whose formulae can be represented as (RE³⁺)(Li¹⁺)₃(Bi³⁻)₂.     

Completing the Series: New Coordination Networks of Composition 3∞[RE2(ADC)3(H2O)6]·2H2O with RE = Pr,Nd, Sm,Eu, Tb,Dy, Ho,Er, Y and ADC2– = Acetylenedicarboxylate (–O2C–C≡C–CO2–)

The crystal structures of ³_∞[RE₂(ADC)₃(H₂O)₆] · 2H₂O (RE = Pr, Nd, Sm, Eu, Tb, Dy) were solved and refined from X‐ray single crystal data. They crystallize in a structure type already known for RE = La, Ce and Gd (P1 , no. 2, Z = 2), which is characterized by REO₉ polyhedra forming dimeric units being the nodes of a 3D framework structure linked by ADC^2– anions (^–O₂C–C≡C–CO₂^– = acetylenedicarboxylate). From synchrotron powder diffraction data it was shown that isostructural coordination networks are formed for RE = Ho, Er, Y, whereas for RE = Tm, Yb, Lu a new structure type crystallizing in a highly complex crystal structure with a large orthorhombic unit cell is found. All compounds are obtained by slow evaporation of an aqueous solution containing RE(OAc)₃ · xH₂O and acetylenedicarboxylic acid (H₂ADC). The coordination networks of composition ³_∞[RE₂(ADC)₃(H₂O)₆] · 2H₂O were thoroughly investigated by thermal analysis and for RE = Eu, Tb, a strong red and green photoluminescence was observed and investigated by means of UV/Vis spectroscopy.     

Oxonium Ions Substituting Cesium Ions in the Structure of the New High‐Pressure Borate HP‐Cs1−x(H3O)xB3O5 (x=0.5–0.7)

The new high‐pressure borate HP‐Cs_1?x(H₃O)_xB₃O₅ (x=0.5–0.7) was synthesized under high‐pressure/high‐temperature conditions of 6 GPa/900 °C in a Walker‐type multianvil apparatus. The compound crystallizes in the monoclinic space group C2/c (Z=8) with the parameters a=1000.6(2), b=887.8(2), c=926.3(2) pm, β=103.1(1)°, V=0.8016(3) nm³, R1=0.0452, and wR2=0.0721 (all data). The boron–oxygen network is analogous to those of the compounds HP‐MB₃O₅, (M=K, Rb) and exhibits all three structural motifs of borates—BO₃ groups, corner‐sharing BO₄ tetrahedra, and edge‐sharing BO₄ tetrahedra—at the same time. Channels inside the boron–oxygen framework contain the cesium and oxonium ions, which are disordered on a specific site. Estimating the amount of hydrogen by solid‐state NMR spectroscopy and X‐ray diffraction led to the composition HP‐Cs_1?x(H₃O)_xB₃O₅ (x=0.5–0.7), which implies a nonzero phase width.     

Synthesen und Kristallstrukturen von neuen Alkalimetall‐Selten‐Erd‐Telluriden der Zusammensetzungen KLnTe2 (Ln = La,Pr, Nd,Gd), RbLnTe2 (Ln = Ce,Nd) und CsLnTe2 (Ln = Nd)

Syntheses and Crystal Structures of New Alkali Metal Rare‐Earth Tellurides of the Compositions KLnTe₂ (Ln = La, Pr, Nd, Gd), RbLnTe₂ (Ln = Ce, Nd) and CsLnTe₂ (Ln = Nd) Of the compounds ALnQ₂ (A = Na, K, Rb, Cs; Ln = rare earth‐metal; Q = S, Se, Te) the crystal structures of the new tellurides KLaTe₂, KPrTe₂, KNdTe₂, KGdTe₂, RbCeTe₂, RbNdTe₂, and CsNdTe₂ were determined by single‐crystal X‐ray analyses. They all crystallize in the α‐NaFeO₂ type with space group R3¯m and three formula units in the unit cell. The lattice parameters are: KLaTe₂: a = 466.63(3) pm, c = 2441.1(3) pm; KPrTe₂: a = 459.73(2) pm, c = 2439.8(1) pm; KNdTe₂: a = 457.83(3) pm, c = 2443.9(2) pm; KGdTe₂: a = 449.71(2) pm, c = 2443.3(1) pm; RbCeTe₂: a = 465.18(2) pm, c = 2533.6(2) pm; RbNdTe₂: a = 459.80(3) pm, c = 2536.5(2) pm, and CsNdTe₂: a = 461.42(3) pm, c = 2553.9(3) pm. Characteristics of the α‐NaFeO₂ structure type as an ordered substitutional variant of the rock‐salt (NaCl) type are layers of corner‐sharing [(A⁺/Ln³⁺)(Te^2—)₆] octahedra with a layerwise alternating occupation by the cations A⁺ and Ln³⁺.     

High‐Pressure Synthesis and Characterization of New Actinide Borates,AnB4O8 (An=Th,U)

New actinide borates ThB₄O₈ and UB₄O₈ were synthesized under high‐pressure, high‐temperature conditions (5.5 GPa/1100 °C for thorium borate, 10.5 GPa/1100 °C for the isotypic uranium borate) in a Walker‐type multianvil apparatus from their corresponding actinide oxide and boron oxide. The crystal structure was determined on basis of single‐crystal X‐ray diffraction data that were collected at room temperature. Both compounds crystallized in the monoclinic space group C2/c (Z=4). Lattice parameters for ThB₄O₈: a=1611.3(3), b=419.86(8), c=730.6(2) pm; β=114.70(3)°; V=449.0(2) ų; R₁=0.0255, wR₂=0.0653 (all data). Lattice parameters for UB₄O₈: a=1589.7(3), b=422.14(8), c=723.4(2) pm; β=114.13(3)°; V=443.1(2) ų; R₁=0.0227, wR₂=0.0372 (all data). The new AnB₄O₈ (An=Th, U) structure type is constructed from corner‐sharing BO₄ tetrahedra, which form layers in the bc plane. One of the four independent oxygen atoms is threefold‐coordinated. The actinide cations are located between the boron–oxygen layers. In addition to Raman spectroscopic investigations, DFT calculations were performed to support the assignment of the vibrational bands.     

Inverse Perovskites (Eu3O)E with E = Sn,In – Preparation,Crystal Structures and Physical Properties

The cubic inverse Perovskites (Eu₃O)In and (Eu₃O)Sn were prepared from the metals and Eu₂O₃ or SnO₂, respectively. For (Eu₃O)In the crystal structure analysis was performed on single crystal X‐ray diffraction data (space group , a = 512.79(3) pm, Z = 1, R_gt(F) = 0.022, wR(F²) = 0.044). The data indicated full occupancy on all sites and a fully ordered structure. According to magnetic susceptibility measurements and X‐ray absorption spectroscopic data at the Eu L_III edge both compounds contain europium in the 4f⁷ (Eu²⁺) electronic state. (Eu₃O)In orders ferromagnetically at 185(5) K, (Eu₃O)Sn shows antiferromagnetic order at 31.4(2) K. Both compounds behave as metallic conductors in electrical resistivity measurements. However, (Eu₃O)In may be classified a metal, while (Eu₃O)Sn is more likely a heavily doped degenerated semiconductor or semimetal according to the absolute values of the resistivity.     

Syntheses and Structures of RE4Pt10In21 (RE = La–Nd)

The isotypic indides RE₄Pt₁₀In₂₁ (RE = La, Ce, Pr, Nd) were prepared by melting mixtures of the elements in an arc‐furnace under an argon atmosphere. Single crystals were synthesized in tantalum ampoules using special temperature modes. The four samples were studied by powder and single crystal X‐ray diffraction: Ho₄Ni₁₀Ga₂₁ type, C2/m, a = 2305.8(2), b = 451.27(4), c = 1944.9(2) pm, β = 133.18(7)°, wR2 = 0.045, 2817 F² values, 107 variables for La₄Pt₁₀In₂₁, a = 2301.0(2), b = 448.76(4), c = 1941.6(2) pm, β = 133.050(8)°, wR2 = 0.056, 3099 F² values, 107 variables for Ce₄Pt₁₀In₂₁, a = 2297.4(2), b = 447.4(4), c = 1939.7(2) pm, β = 132.95(1)°, wR2 = 0.059, 3107 F² values, 107 variables for Pr₄Pt₁₀In₂₁, and a = 2294.7(4), b = 446.1(1), c = 1938.7(3) pm, β = 132.883(9)°, wR2 = 0.067, 2775 F² values, 107 variables for Nd₄Pt₁₀In₂₁. The 8j In2 positions of all structures have been refined with a split model. The In1 sites of the lanthanum and the cerium compound show small defects, leading to the refined composition La₄Pt₁₀In_20.966(6) and Ce₄Pt₁₀In_20.909(6) for the investigated crystals. The same position shows Pt/In mixing in the praseodymium and neodymium compound leading to the refined compositions Pr₄Pt_10.084(9)In_20.916(9) and Nd₄Pt_10.050(9)In_20.950(9). All platinum atoms have a tricapped trigonal prismatic coordination by rare‐earth metal and indium atoms. The shortest interatomic distances occur for Pt–In followed by In–In. Together, the platinum and indium atoms build up three‐dimensional [Pt₁₀In₂₁] networks in which the rare earth atoms fill distorted pentagonal tubes. The crystal chemistry of RE₄Pt₁₀In₂₁ is discussed and compared with the RE₄Pd₁₀In₂₁ indides and isotypic gallides.     

Synthesis,Luminescence and Nonlinear Optical Properties of Homoleptic Tetracyanamidogermanates ARE[Ge(CN2)4] (A = K,Cs, and RE = La,Ce, Pr,Nd, Sm,Eu, Gd)

Two new series of tetracyanamidogermanates were prepared by solid‐state reaction of appropriate amounts of REF₃ (RE = rare earth), A₂[GeF₆] (A = alkaline), and Li₂(CN₂) in evacuated silica tubes. Powder X‐ray diffraction patterns of crystalline samples of KRE[Ge(CN₂)₄] and CsRE[Ge(CN₂)₄] were indexed isotypically to KRE[Si(CN₂)₄] and RbRE[Ge(CN₂)₄], respectively. Luminescence properties of Ce³⁺, Eu³⁺, and Tb³⁺ doped compounds and non‐linear optical properties (NLO) of KRE[Ge(CN₂)₄] are reported.     

Syntheses and Crystal Structures of Ln(phen)2(NO3)3 with Ln = Pr,Nd, Sm,Eu, Dy,and phen = 1,10‐phenanthroline

Five new complex compounds of the formula Ln(phen)₂(NO₃)₃ were prepared. The X‐ray structural analyses indicate that they crystallize isostructurally in the monoclinic space group C2/c (no. 15) with cell dimensions for example for Pr(phen)₂(NO₃)₃: a = 11.194(1) Å, b = 18.095(2) Å, c = 13.101(2) Å, β = 100.52(1)°, V = 2609.1(6) ų, Z = 4. The crystal structures consist of [Ln(phen)₂(NO₃)₃] complex molecules. The rare earth atoms are coordinated by four N atoms of two phen ligands and six O atoms of three nitrato groups to complete a distorted bicapped dodecahedron. The [Ln(phen)₂(NO₃)₃] complex molecules are assembled via π‐π stacking interactions between the neighboring phen ligands to form 1D columnar chains, which are then arranged in the crystal structures according to pseudo 1D close‐packed patterns.     

Synthesis of Er5(BO3)2F9 and Properties of RE5(BO3)2F9 (RE = Er,Yb)

Er₅(BO₃)₂F₉ was synthesised under conditions of 3 GPa and 800 °C in a Walker‐type multianvil apparatus. The crystal structure was determined on the basis of single‐crystal X‐ray diffraction data, collected at room temperature. Er₅(BO₃)₂F₉ is isotypic to the recently synthesised Yb₅(BO₃)₂F₉ and crystallises in C2/c with the lattice parameters a = 2031.2(4) pm, b = 609.5(2) pm, c = 824.6(2) pm, and β = 100.29(3)°. The physical properties of RE₅(BO₃)₂F₉ (RE = Er, Yb) including high temperature behaviour and single crystal IR‐ / Raman spectroscopy were investigated.