Space Group P3m1 Research Articles

Effect of Fe alloying on the thermoelectric performance of Cu2Te

Copper telluride belongs to the “Phonon Liquid Electron Crystal” (PLEC) class of materials owing to its mobile Cu ions which migrate easily inside the crystal lattice. The mobile copper ions scatter phonons and lead to low thermal conductivity making it a suitable choice as a thermoelectric material. However, the formation of copper vacancies results in high hole carrier concentration (∼1021 cm−3) leading to poor Seebeck coefficient and degrades its overall thermoelectric efficiency. In this work, we aim at improving the thermoelectric transport properties of Cu2Te by alloying with Fe. The alloys of Cu2-xFexTe (where x varies from 0 to 0.06) were synthesized via solid-state synthesis followed by compaction in an induction hot press system. The formation of the trigonal phase (space group P3m1) of Cu2Te and the solubility of Fe ∼ x = 0.05 in Cu2-xFexTe is confirmed by means of X-ray Diffraction and backscattered electron micrographs. The decrease in electrical conductivity and the Hall carrier concentration and increase in the Seebeck coefficient with increasing Fe content signifies the compensation of holes by the electrons contributed from the trivalent Fe. The specific heat capacities of the Fe substituted samples were higher than the Dulong Petit limit of 3NkB, which implies that “liquid-like” behaviour of the Cu ions has been suppressed. This is because the Fe atoms act as barriers to the Cu ion diffusion. Due to the maximum power factor (∼0.47 mW m−1 K−2) and minimum thermal conductivity (∼2.19 W m−1 K−1), the maximum figure of merit of ∼0.16 at 750 K was obtained for the sample Fe0.03. It is hypothesized that the substitution of Fe not only helped to control the high carrier concentration but also restricted the cationic diffusion in Cu2Te. Hence, the present study points to a possibility of synergistically improving the thermoelectric properties as well as suppressing the ionic diffusivity in PLEC materials.

NbSeTe—a new layered transition metal dichalcogenide superconductor

Transition metal dichalcogenides (TMDCs) usually exhibit layered polytypic structures due to the weak interlayer coupling. 2H-NbSe2 is one of the most widely studied in the pristine TMDC family due to its high superconducting transition temperature (Tc = 7.3 K) and the occurrence of a charge-density wave (CDW) order below 33 K. The coexistence of CDW with superconductivity poses an intriguing open question about the relationship between Fermi surface nesting and Cooper pairing. Past studies of this issue have mostly been focused on doping 2H-NbSe2 by 3d transition metals without significantly changing its crystal structure. Here we replaced the Se by Te in 2H-NbSe2 in order to design a new 1T polytype layered TMDC NbSeTe, which adopts a trigonal structure with space group Pm1. We successfully grew large size and high-quality single crystals of 1T-NbSeTe via the vapor transport method using I2 as the transport agent. Temperature-dependent resistivity and specific heat data revealed a bulk Tc at 1.3 K, which is the first observation of superconductivity in pure 1T-NbSeTe phase. This compound enlarged the family of superconducting TMDCs and provides an opportunity to study the interplay between CDW and superconductivity in the trigonal structure.

Structure of Cubic Al73.8Pd13.6Fe12.6 Phase with High Al Content

A cubic ternary phase Al73.8Pd13.6Fe12.6 (designated C′ phase), with very high Al content (Al/TM = 2.82, TM denotes transition metal) was prepared by spark plasma sintering (SPS). Its crystal structure was determined by combing single-crystal X-ray diffraction (SXRD) and scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) measurements. The crystal structure of the new phase can be described with a small unit cell (a = 7.6403(2) Å; space group Pm3, No. 200) as that of Al2.63Rh (a = 7.6692(1) Å; space group P23, No. 195) while different from those of the reported Al39Pd21Fe2 (a = 15.515(1) Å; space group Fm3, No. 202) and Al69Pd17Fe14 (a = 15.3982(2) Å; space group Im3, No. 204) compounds, which both adopt a double length unit cell in the Al–Pd–Fe system. The mechanism of distributing more Al atoms in the new phase was compared with that of the Al2.63Rh phase by analyzing their site symmetry and the corresponding site of occupancies (SOF). Furthermore, relations of the C′ phase to the reported Al69Pd17Fe14 (designated C1 phase) and Al39Pd21Fe2 (designated C2 phase) phases were investigated by analyzing their building units with the “nanocluster” method in the ToposPro package.

Thin Film of Perovskite (Mixed-Cation of Lead Bromide FA1−xMAxPbBr) Obtained by One-Step Method

Perovskite materials for solar cell applications were prepared by a one-step method. In the following work, the spin coating technique was used for organic–inorganic hybrid perovskite formamidinium lead tribromide (FAPbBr3), methylammonium lead tribromide (MAPbBr3) and formamidinium methylammonium lead tribromide (FA1−xMAxPbBr3).Thin films of mixed FA1−xMAxPbBr3 (x = 0–1) perovskites deposited on indium tin oxide glass substrates were obtained by mixing FAPbBr3 and MAPbBr3 in different proportions. Structural x-ray diffraction (XRD), morphological (Scanning Electron Microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) and optical (uv–visible spectroscopy (UV–Vis) proprieties were investigated for all synthesized perovskites as a function of the MA/FA ratio. The (XRD) analysis shows the formation of a cubic-phase perovskite with space group Pm-3 m in the composition range 0 ≤ x ≤ 1. High absorbance levels were obtained in the infrared region 500-900 nm for mixed perovskites FAMAPbBr3. The estimated energy band-gap from the absorbance spectral measurements for FAMAPbBr3 thin films was in the range of 2.2 eV for FAPbBr3 and 2.3 eV for MAPbBr3, respectively. The photoluminescence emission of mixed FA/MA perovskite thin films was located in intermediate values between 580 nm and 555 nm.

Hydrocarbons under Pressure: Phase Diagrams and Surprising New Compounds in the C–H System

Understanding the high-pressure behavior of C-H system is of great importance due to its key role in organic, bio-, petroleum and planetary chemistry. We have performed a systematic investigation of the pressure-composition phase diagram of the C-H system at pressures up to 400 GPa using evolutionary structure prediction coupled with ab initio calculations and discovered that only saturated hydrocarbons are thermodynamically stable. Several stable methane-hydrogen co crystals are predicted: 2CH4 * H2, earlier obtained experimentally, is predicted to have I4/m space group and 2-90 GPa stability range at 0 K, and two new thermodynamically stable compounds 2CH4 * 7H2 (P-3m1 space group) and CH4 * 9H2 (Cm space group), as potential energy storage materials. P21/c phase of methane is predicted to be stable at pressures < 8 GPa; bulk graphane (CH) was shown to be thermodynamically stable at 7-18 and 18-50 GPa and 0 K in the P-3m and Cmca phases, respectively; polyethylene is shown to have a narrow field of stability. We report the p-T-x phase diagram of the C-H system and p-T phase diagram of CH4.

KCu7P3: A Two-Dimensional Noncentrosymmetric Metallic Pnictide

We report a 2D material, KCu7P3, with a noncentrosymmetric structure (trigonal space group P31m, a = 6.9637(2) Å, c = 24.1338 (10) Å), which forms both from a molten potassium polyphosphide flux and from the elements. This phase consists of infinite [Cu7P3]- layers with hexagonal P sheets separated by K+ ions. The structure of the layers is unique but related to both Cu3P and the CaCu4P2 structure-types. Single-crystal refinement reveals extensive disorder within the Cu3P-like slabs. KCu7P3 is paramagnetic and exhibits a room temperature resistivity of ∼335 μΩ cm with a metal-like temperature dependence. The metallic character is supported by density functional theory electronic structure calculations. Hall and Seebeck effect measurements yield p-type behavior with a hole mobility of ∼15 cm2 V-1 s-1 at 300 K and a carrier concentration on the order of 1021 cm-3. KCu7P3 is chemically stable in ambient conditions, as well as in aqueous neutral and acidic solutions.

New Deep-Blue-Emitting Ce-Doped A4-mBnC19+2mX29+m (A = Sr, La; B = Li; C = Si, Al; X = O, N; 0 ≤ m ≤ 1; 0 ≤ n ≤ 1) Phosphors for High-Color-Rendering Warm White Light-Emitting Diodes.

A new sialon Eu3.60LiSi13.78Al6.03O6.82N22.59 has been discovered via the single-particle diagnosis approach. Its crystal structure (space group P3m1) was solved and refined from single-crystal X-ray diffraction data. It has the interesting feature of two types of disorder at the Eu2 site: positional disorder (Eu2a/Eu2b) and substitutional disorder with (Si/Al)2(O/N). The structure is generalized to the formula A4-mBnC19+2mX29+m (A = Sr, La, Eu, Ce; B = Li; C = Si, Al; X = O, N; 0 ≤ m ≤ 1; 0 ≤ n ≤ 1), of which Sr3.61LiSi14.27Al5.61O6.19N23.25 (Sr-sialon, m = 0.41, n = 1) and La2.85Sr0.76LiSi14.86Al4.93O2.89N26.51 (LaSr-sialon, m = 0.40, n = 1) are two examples that have been obtained as a single-phase powder. Sr-sialon:Eu and LaSr-sialon:Eu both show blue to yellow emission, depending on the Eu concentration, whereas Sr-sialon:1% Ce shows a deep-blue emission band centered at 422 nm with a full width at half-maximum of 80 nm and an internal quantum efficiency of 80% (λex = 355 nm). The latter phosphor has very good thermal stability of both emission intensity and color. A white light-emitting diode (LED) containing the newly discovered Sr-sialon:5% Ce as the blue phosphor component shows excellent color-rendering indices (Ra = 96 and R12 = 97) with a correlated color temperature of 4255 K. This indicates that Sr-sialon:Ce is a highly promising deep-blue phosphor for illumination grade white LEDs.

Synthesis and semiconducting behavior of Zr (Cu, Fe) Se2−δ single crystals

We report the synthesis and electrical resistivity of Zr (Cu, Fe)Se2−δ single crystals with layered hexagonal structure (space group P-3M1, No. 164). Se vacancies are found existed in all pristine samples. Adding Fe into the raw materials results in substitution of Zr and the lattice parameters are found almost unaffected while that with Cu results in intercalation of the van der Waals gap and the lattice parameters are expanded essentially. All compounds display semiconducting behavior, i.e. negative temperature dependence, and the activation energy (Δ) estimated from thermal activation model are in the range of 50–200 meV. We also observe spin-glass-like behavior in the Fe-containing samples.

Ognitite, NiBiTe, a new mineral species, and Co-rich maucherite from the Ognit ultramafic complex, Eastern Sayans, Russia

AbstractWe describe the new species ognitite, NiBiTe, and a Co-rich variety of maucherite, hitherto unreported; both were discovered in the Ognit ultramafic complex of Neoproterozoic age in Eastern Sayans, Russia. The mean composition of ognitite (n = 7) is: Ni 17.05, Fe 0.07, Cu 0.14, Pd 0.14, Te 32.53, Bi 49.64, total 99.57 wt.%, corresponding to: (Ni1.11Cu0.008Fe0.005Pd0.005)Σ1.13Bi0.90Te0.97 (Σ atoms = 3 apfu). Ognitite is trigonal, space group P3m1 [R1 = 0.0276 for 81 reflections with Fo &gt; 4σ(Fo)]. The unit-cell parameters derived from the single-crystal X-ray diffraction data are: a = 3.928(1) Å, c = 5.385(1) Å and V = 71.95(4) Å3, with Z = 1. The c:a ratio is 1.37. The powder X-ray diffraction data obtained on the same fragment used for the single-crystal study are: a = 3.9332(4) Å, c = 5.3920(6) Å and V = 72.24(1) Å3. Ognitite exhibits the brucite-type structure with edge-sharing NiTe3Bi3 octahedra forming sheets parallel to (0001). It is related to melonite, but is distinct compositionally by the extreme Bi-enrichment (melonite and its synthetic analogue contain &lt;0.4 Bi apfu), and structurally as Bi and Te are ordered at two distinct sites, leading to the loss of the centre of symmetry in ognitite.At more than 9 wt.% Co, or ~2 apfu Co, the core of Co-rich maucherite [(Ni,Co)11As8] in a zoned crystal, which is surrounded by Co-depleted orcelite, far surpasses the norm (≤1 and up to 3.9 wt.% Co). The unit-cell parameters of the Co-rich maucherite are: a = 6.85(2) and c = 21.83(5) Å, which are based on results of synchrotron micro-Laue diffraction.The host rock consists of serpentine, clinochlore (Mg# 95–97) and skeletal chromite. We favour the metastable crystallisation of fluid-saturated globules of a sulfide–arsenide melt to explain the anomalous compositions of ore minerals at Ognit. These anomalies seem consistent with rapid cooling in a fluid-enriched system, possibly related to late-stage degassing of the magma, as reflected in a prominent metasomatic aureole at the contact with the enclosing gneissic rocks.

Structural and Mössbauer study of (Sb0.70Te0.30)100-x Snx alloys with x = 0, 2.5, 5.0 and 7.5

(Sb0.70Te0.30)100-xSnx alloys (with x = 0, 2.5, 5.0 and 7.5 at. %) have been synthesized and characterized in order to determine the crystalline structure and properties of materials obtained upon solidification and to extract information about the location of the Sn atom in the Sb-Te matrix. Powder X-ray diffraction (XRD) has been used to determine the crystalline structure, whereas Mössbauer spectroscopy has been utilized to determine the localization and the local structure of the Sn atom in the Sb-Te matrix through the hyperfine interactions of the 119Sn probe with its environment. We found that Sb70Te30 crystallizes in a trigonal structure belonging to P-3m1 space group, while the doping with Sn leads to structural distortions of the unit cell that can be described, for all the Sn concentrations, with the C2/m space group. The hyperfine parameters indicate that tin behaves as Sn(II) and has a slightly distorted environment. Finally, in order to extract all the information that the experimental results contain and to determine the preferential site occupied by the Sn impurities in the Sb-Te matrix, we have performed ab-initio calculations within the framework of the Density Functional Theory. The theoretical results enable us to determine the structural and electronic ground state of (Sb0.70Te0.30)100-xSnx compounds and to confirm that Sn atoms substitute Sb atoms in the Sb-Te host.

Ab initio studies of copper hydrides under high pressure

The crystal structure, electronic structure, and superconductivity of copper hydrides at high pressure have been studied by ab initio calculation. Consistent with experimental report, results show that the predicted stoichiometry Cu2H with the P-3m1 space group is stable above 16.8 GPa. The stoichiometry of CuH with the Fm-3m space group is predicted to be synthesized above 30 GPa, but it is metastable and dynamical instable up to 120 GPa. The electronic band calculations reveal that Cu2H is a good metal at a stable pressure range, whereas CuH is an insulator. Moreover, the other hydrogen-rich compounds CuH2 and CuH3 are thermodynamically and dynamically unstable, respectively. The calculated superconducting transition temperature (Tc) of Cu2H at 40 GPa is 0.028 K by using the Allen-Dynes modified McMillan equation.

New Quaternary Compounds R&lt;sub&gt;3&lt;/sub&gt;MnAl&lt;sub&gt;3&lt;/sub&gt;Ge&lt;sub&gt;2&lt;/sub&gt; (R - Rare Earth)

Nine new quaternaryR3MnAl3Ge2alumogermanides (R= Sm, Gd-Lu) were synthesized by arc melting and their crystal structures were studied by X-ray powder diffraction. All of the compounds crystallize in hexagonal Y3NiAl3Ge2-type structures: Pearson symbolhP9, space groupP-62m. The unit-cell parameters of the isotypic compounds decrease with decreasing radius of the rare-earth metal. The hexagonal structure type Y3NiAl3Ge2(Z= 1) is a quaternary ordering variant of the binary type Fe2P (Z= 3) and the ternary types β1-K2UF6, Lu3CoGa5, Zr3Cu4Si2(Z= 1), ZrNiAl (Z= 3). It belongs to the family of structures with trigonal prismatic coordination of the small atoms.

A Novel Family of Np(VI) Oxysalts: Crystal Structures, Calorimetry, Thermal Behavior, and Comparison with U(VI) Compounds

Phase formation in the mixed sulfate–selenate Np(VI)-bearing aqueous system has been investigated. The obtained crystalline compounds, Cs2[(NpO2)2(TO4)3] (T = S, Se), crystallize in the tetragonal system, space group P421m, with a = 9.5737(3)–9.817(3) A, c = 8.0824(4)–8.111(3) A, and V = 740.79(6)–781.8(6) A3, and have been chemically characterized. Single-crystal X-ray diffraction experiments at various temperatures were used to define the thermal behavior of the crystal structures relative to the S/Se ratio. The thermal behavior of mixed sulfate–selenate and pure selenate compounds is anisotropic, with the highest thermal expansion in the direction perpendicular to the sheets of Np-bearing polyhedra, while the structure of the pure sulfate compound experiences almost isotropic thermal expansion with slightly higher expansion within the layer, which is explained by the influence of stronger Cs–O bonding. High-temperature drop solution calorimetry was used to derive the enthalpies of formation of the Cs+...

From 0D Cs3Bi2I9 to 2D Cs3Bi2I6Cl3: Dimensional Expansion Induces a Direct Band Gap but Enhances Electron–Phonon Coupling

Alternative all-inorganic halide perovskites are sought to replace the hybrid lead halide perovskites because of their increased stability. Here, the (111)-oriented defect perovskite family A3M2X9 based on trivalent M3+ is expanded through the use of mixed halides, resulting in Cs3Bi2I6Cl3. This compound shares the (111)-oriented 2D bilayer structure of α-Cs3Sb2I9 (space group P3m1), with Cl occupying the bridging positions of the bilayers and I in the terminal sites, in contrast to the parent compound Cs3Bi2I9, which consists of 0D molecular [Bi2I9]3– dimers. The increased dimensionality induces a direct band gap as calculated by density functional theory but has an absorption edge of 2.07 eV, nearly identical to the indirect band gap compound Cs3Bi2I9. Intriguingly, there is a remarkable lack of Cl orbital contribution to the band edge states of Cs3Bi2I6Cl3, despite Bi–Cl bonds binding all octahedra together. This highlights the importance of interlayer interactions in the defect perovskite family, whi...

Synthesis, crystallographic structure and thermodynamic properties of T2-Al2MgC2

T2-Al2MgC2 was synthesized from the elements in a Mg-Al melt at 1000 °C using sealed Ta crucibles. Single crystals of T2-Al2MgC2 were extracted by evaporating the Mg-Al matrix. The crystal structure of T2-Al2MgC2 was refined for the first time on the basis of single-crystal X-ray diffraction. The crystal is trigonal (space group P-3m1, Z = 1) with lattice parameters of a = 3.3767(11) Å, c = 5.807(2) Å and V = 57.34(5) Å3. Based on the refined crystal structure, DFT calculations were conducted to evaluate the thermodynamic properties and the electronic structure of the phase. The heat of formation of T2-Al2MgC2 was calculated to be −23.6 kJ/mol of atoms at 298 K. The heat capacity of T2-Al2MgC2 was measured by DSC from 300 to 871 K and calculated by DFT from 0 to 1000 K. Based on the calculated heat capacity, the entropy of formation of the phase at 298 K was determined to be 70.0 J/mol/K. The band structure and the electronic density of state of T2-Al2MgC2 was calculated leading to an indirect band gap value of 1.73 eV.

Exploring new insights in BAlN from evolutionary algorithms ab initio computations

BN-AlN alloys are potential candidates to achieve wide band gap material for ultraviolet device applications. By combing density functional theory and evolutionary structure predictions, we systematically explore the thermodynamic, mechanical, dynamical and optical properties of BxAl1−xN alloys. Through structure search, three compounds (cubic (BAl3N4, and B3AlN4, space group P-43m), and tetragonal (BAlN2, space group P-42m)) have been predicted. The calculated relative large formation enthalpies suggest that large miscibility gap exists in BAlN alloys. In addition, computed elastic constants and phonon show that these structures are mechanically and dynamically stable. From the state of the art LDA-1/2 we show that the direct band gap of BN-AlN evinces strong deviation from a linear dependence on B composition. We found -in particular- giant direct band gap bowing parameter of b∼11.6 eV for the entire range of composition, where b parameter is found to be sensitive to composition x. From a detailed analysis of the physical origin of the optical gap bowing b, we found that structural and chemical contributions play the most significant effects behind the huge optical band gap bowing parameter of BAlN alloys.

Synthesis, structure and magnetic properties of a new phase of cobalt(II) hydroxyl phosphate γ-Co2(PO4)(OH) with a warping two-legs ladder chain

A new phase of cobalt(II) hydroxyl phosphate γ-Co2(PO4)(OH) has been successfully synthesized through a conventional hydrothermal method. This compound crystallizes in the trigonal system of space group P31m, showing a warping two-legs spin ladder chain structure arranged in an unusual triangular network, in which a new spin-lattice of (3, 6, 4, 6)(4, 62) is built by magnetic Co2+ ions. Magnetic measurements indicate that γ-Co2(PO4)(OH) may show a spin-glass behavior at low temperature.

Structural Determination and Nonlinear Optical Properties of New 1T‴-Type MoS2 Compound.

Noncentrosymmetric MoS2 semiconductors (1H, 3R) possess not only novel electronic structures of spin-orbit coupling (SOC) and valley polarization but also remarkable nonlinear optical effects. A more interesting noncentrosymmetric structure, the so-called 1T‴-MoS2 layers, was predicted to be built up from [MoS6] octahedral motifs by theoreticians, but the bulk 1T‴ MoS2 or its single crystal structure has not been reported yet. Here, we have successfully harvested 1T‴ MoS2 single crystals by a topochemical method. The new layered structure is determined from single-crystal X-ray diffraction. The crystal crystallizes in space group P31m with a cell of a = b = 5.580(2) Å and c = 5.957(2) Å, which is a √3 a × √3 a superstructure of 1T MoS2 with corner-sharing Mo3 triangular trimers observed by the STEM. 1T‴ MoS2 is verified to be semiconducting and possesses a band gap of 0.65 eV, different from metallic nature of 1T or 1T' MoS2. More surprisingly, the 1T‴ MoS2 does show strong optical second-harmonic generation signals. This work provides the first layered noncentrosymmetric semiconductor of edge-sharing MoS6 octahedra for the research of nonlinear optics.

Exploration of the structural and optical properties of a red-emitting phosphor K2TiF6:Mn4+**Project supported by the National Natural Science Foundation of China (Grant No. 11574220), Fundamental Research Funds for the Central Universities, China (Grant No. SWU118055), and the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund (the second phase), China.

The exploration of the appropriate red phosphor with good luminescence properties is an important issue in the development of current white light-emitting diode (WLED) devices. Transition metal Mn-doped compounds are fascinating luminescent materials. Herein, we performed a systematic theoretical study of the microstructure and optical properties of K2TiF6:Mn4+ using the CALYPSO structure search method in combination with first-principles calculations. We uncovered a novel structure of K2TiF6:Mn4+ with space group P-3m1 symmetry, where the impurity Mn4+ ions are accurately located at the center of the MnF6 octahedra. Based on our developed complete energy matrix diagonalization (CEMD) method, we calculated transition lines for 2Eg → 4A2, 4A2 → 4T2, and 4A2 → 4T2 at 642, nm, 471 nm, and 352 nm, respectively, which are in good agreement with the available experimental data. More remarkably, we also found another transition (4A2 → 2T2) that lies at 380 nm, which should be a promising candidate for laser action.

Synthesis and Characterization of Three New Lithium‐Scandium Hexathiohypodiphosphates: Li4–3xScxP2S6 (x = 0.358), m‐LiScP2S6, and t‐LiScP2S6

We report the first examples of lithium rare earth metal hexathiohypodiphosphates(IV). Three new lithium‐scandium hexathiohypodiphosphates(IV) were synthesized and characterized. The compounds crystallize in three different structure types, featuring isolated ethane‐like [P2S6]4– hexathiohypodiphosphate(IV) units. Li2.926Sc0.358P2S6 or Li4–3xScxP2S6 (x = 0.358) crystallizes in the space group P31m (no. 162) with a = b = 6.0966(5) Å, c = 6.5866(6) Å, V = 212.02(4) Å3, and Z = 1. The compound is isostructural to Li2FeP2S6 as well as the Li ion conductor Li4–2xMgxP2S6 (x = 1/3, 2/3). Monoclinic LiScP2S6 was found to be a layered compound with van der Waals gaps. The layers consist of edge sharing octahedra that are occupied by Li, Sc, and P2 in an alternating fashion. It is isostructural to LiAlP2S6 and crystallizes in the space group C2/c (no. 15) with a = 6.933(1) Å, b = 10.754(2) Å, c = 11.694(2) Å, β = 94.41(3)°, V = 869.3(3) Å3, and Z = 4. Trigonal LiScP2S6 crystallizes in the space group P31c (no. 163) with a = b = 6.363(1) Å, c = 12.386(3) Å, V = 434.3(2) Å3, and Z = 2, and is isostructural to AgInP2S6 and AgScP2S6. Its structure is closely related to the monoclinic version, except that trigonal LiScP2S6 features disordered [P2/2P6/6S6]4– units. The new phases were investigated by Raman spectroscopy, thermal analysis, and DFT calculations. We further demonstrate that Li4–3xScxP2S6 shows significantly enhanced Li ion conductivity compared to the parent compound Li4P2S6.