Experimental and Theoretical Force Constants as Meaningful Indicator for Interatomic Bonding Characteristics and the Specific Case of Elemental Antimony.

Stable Sb exhibits a rhombohedral structure, often referred to as distorted primitive cubic, with each Sb atom having three short and three longer first neighbor bonds. However, this crystal structure can also be interpreted as being layered, putting emphasis on only three short first neighbor bonds. Therefore, temperature-dependent extended X-ray absorption fine structure (EXAFS) spectroscopy is carried out at the Sb K-edge in order to obtain more detailed information on local structural and vibrational properties.

PTaN (x=0.1-0.15): A Phosphorus Tantalum Nitride Featuring Mixed-Valent Tantalum and P/Ta Disorder Visualized by Scanning Transmission Electron Microscopy.

We report on the synthesis, crystal, and electronic structure, as well as the magnetic, and electric properties of the phosphorus-containing tantalum nitride PTaN (x=0.1-0.15).

Multicationic Tetrahedra Networks: Alkaline-Earth-Centered Polyhedra and Non-Condensed AlN-Octahedra in the Imidonitridophosphates AEAlPN(NH) (AE=Ca, Sr, Ba).

A series of isostructural imidonitridophosphates AEAlPN(NH) (AE=Ca, Sr, Ba) was synthesized at high-pressure/high-temperature conditions (1400 °C and 5-9 GPa) from alkaline-earth metal nitrides or azides CaN/Sr(N)/Ba(N) and the binary nitrides AlN and PN. NHF served as a hydrogen source and mineralizing agent. The crystal structures were determined by single-crystal X-ray diffraction and feature a three-dimensional network of vertex-sharing PN-tetrahedra forming diverse-sized rings that are occupied by aluminum and alkaline earth ions.

CrSiPN-A Chromium(+IV) Nitridosilicate Phosphate with Amphibole-Type Structure.

The first nitridic analog of an amphibole mineral, the quaternary nitridosilicate phosphate CrSiPN was synthesized under high-pressure high-temperature conditions at 1400 °C and 12 GPa from the binary nitrides CrN, SiN and PN, using NHN and NHF as additional nitrogen source and mineralizing agent, respectively. The crystal structure was elucidated by single-crystal X-ray diffraction with microfocused synchrotron radiation (C2/m, a=9.6002(19), b=17.

Incommensurately Modulated CuPbSbSe in the Lillianite Structure Type.

Samples with the nominal composition CuPbSbSe mainly contain a phase with incommensurately modulated lillianite-type structure with the respective composition. Single crystal diffraction with synchrotron radiation enabled a detailed refinement using the superspace group (α00)00 with lattice parameters = 4.16537(5), = 14.

CuSeTe ( = 0.2-0.7): A Series of Narrow Band Gap Semiconductors with Low Thermal Conductivity at Ambient Temperature.

Coinage metal chalcogenides offer ideal prerequisites for high thermoelectric performance and sensor applications, with their usually low lattice thermal and high electrical conductivity, as well as small band gaps. In the solid solution CuSeTe we synthesized phase pure materials with = 0.2-0.

Tetra-Face-Capped Octahedra in a Tetrahedra Network - Structure Determination and Scanning Transmission Electron Microscopy of SrAl P N O F.

Tetrahedra-based nitridophosphates show a rich structural chemistry, which can be further extended by incorporating cations in higher coordinated positions, for example, in octahedral voids or by substituting the nitrogen atoms in the network with other anions. Following this approach, SrAl P N O F was synthesized at high-temperature and high-pressure conditions using a multianvil press (1400 °C, 5 GPa) starting from Sr(N ) , c-PON, P N , AlN, and NH F. SrAl P N O F crystallizes in space group with a=11.

Combining MN Octahedra and PN Trigonal Bipyramids in the Mica-like Nitridophosphates MP N (M=Al, In).

Layered silicates are a very versatile class of materials with high importance to humanity. The new nitridophosphates MP N (M=Al, In), synthesized from MCl , P N and NH N in a high-pressure high-temperature reaction at 1100 °C and 8 GPa, show a mica-like layer setup and feature rare nitrogen coordination motifs. The crystal structure of AlP N was elucidated from synchrotron single-crystal diffraction data (space group Cm (no.

Modular Principle for Complex Disordered Tetrahedral Frameworks in Quenched High-Pressure Phases of Phosphorus Oxide Nitrides.

Invited for the cover of this issue are the groups of Oliver Oeckler at Leipzig University and Wolfgang Schnick at University of Munich (LMU). The image background depicts a diffraction pattern of an intergrown crystal containing P O N as a night sky. P O N and P O N form complex disordered frameworks, a cutout of which symbolizes the earth's surface (which mainly contains silicates with related building blocks).

Comprehensive Investigation of Anion Species in Crystalline Li ion Conductor Li [P O N ]O (x≈1.9(3)).

The Li ion conductor Li [P O N ]O (x≈1.9) has been synthesized from P N , Li N and Li O in a Ta ampoule at 800 °C under Ar atmosphere. The cubic compound crystallizes in space group with a=12.

Modular Principle for Complex Disordered Tetrahedral Frameworks in Quenched High-Pressure Phases of Phosphorus Oxide Nitrides.

The crystal structures of the new phosphorus oxide nitrides P O N and P O N , which were synthesized from amorphous phosphorus oxide nitride imide, exhibit complex frameworks built up from P(O,N) tetrahedra. The latter form various chain-like building units with various degrees of branching. These modular units can be combined and arranged in different ways, which leads to closely related structures and several disordered configurations in each compound.

Pnictide-Capped Butterfly Cluster in the Crystal Structure of Nb ( = N, P; = Cl, Br, I).

Niobium pnictide halides Nb ( = N, P; = Cl, Br, I) are reported with their average crystal structures. Individual pnictide-capped butterfly cluster cores [NbP] in the structure are interconnected into two-dimensional layers, with their electronic and magnetic properties being analyzed.

Temperature-dependent Cu and Ag ion mobility and associated changes of transport properties in pavonite-type CuAgBiSe.

CuAgBiSe, the first quaternary compound in the system Cu/Ag/Bi/Se, was obtained from the elements by melt synthesis after pre-reaction and annealing steps. It exhibits a P pavonite-type crystal structure in the spacegroup 2/, which consists of NaCl-type building blocks extending in two dimensions that are separated by rods of edge-sharing BiSe polyhedra and "clusters" of several partially occupied Cu atom sites. Temperature-dependent single crystal X-ray diffraction up to 350 °C helped to explain thermoelectric properties.

Discovery of Two Polymorphs of TiP N Synthesized from Binary Nitrides.

TiP N was obtained from the binary nitrides TiN and P N upon addition of NH F as a mineralizer at 8 GPa and 1400 °C. An intricate interplay of disorder and polymorphism was elucidated by in situ temperature-dependent single-crystal X-ray diffraction, STEM-HAADF, and the investigation of annealed samples. This revealed two polymorphs, which consist of dense networks of PN tetrahedra (degree of condensation κ=0.

Nitridic Analogs of Micas AESi P N (NH) (AE=Mg, Mg Ca , Ca, Sr).

We present the first nitridic analogs of micas, namely AESi P N (NH) (AE=Mg, Mg Ca , Ca, Sr), which were synthesized under high-pressure high-temperature conditions at 1400 °C and 8 GPa from the refractory nitrides P N and Si N , the respective alkaline earth amides, implementing NH F as a mineralizer. The crystal structure was elucidated by single-crystal diffraction with microfocused synchrotron radiation, energy-dispersive X-ray spectroscopic (EDX) mapping with atomic resolution, powder X-ray diffraction, and solid-state NMR. The structures consist of typical tetrahedra-octahedra-tetrahedra (T-O-T) layers with P occupying T and Si occupying O layers, realizing the rare motif of sixfold coordinated silicon atoms in nitrides.

High-Pressure Synthesis of Sc P N O and Ti P N O by Activation of the Binary Nitrides ScN and TiN with NH F.

Multinary transition metal nitrides and oxonitrides are a versatile and intriguing class of compounds. However, they have been investigated far less than pure oxides. The compounds Sc P N O and Ti P N O have now been synthesized from the binary nitrides ScN and TiN, respectively, by following a high-pressure high-temperature approach at 8 GPa and 1400 °C.

Structure Elucidation of Complex Endotaxially Intergrown Lanthanum Barium Oxonitridosilicate Oxides by Combination of Microfocused Synchrotron Radiation and Transmission Electron Microscopy.

Single-crystalline domains in intergrown microcrystalline material of the new compounds Ba La [Si N O ]O :Ce and Ba La [Si N O ]O :Ce were identified by transmission electron microscopy (TEM). Precise diffraction data from these domains were collected with microfocused synchrotron radiation so that crystal structure elucidation of the complex disordered networks became possible. They are composed of two different interconnected slabs of which one is similar in both compounds, which explains their notorious intergrowth.

High-Pressure High-Temperature Synthesis of Mixed Nitridosilicatephosphates and Luminescence of AESiP N :Eu (AE=Sr, Ba).

Tetrahedra-based nitrides with network structures have emerged as versatile materials with a broad spectrum of properties and applications. Both nitridosilicates and nitridophosphates are well-known examples of such nitrides that upon doping with Eu exhibit intriguing luminescence properties, which makes them attractive for applications. Nitridosilicates and nitridophosphates show manifold structural variability; however, no mixed nitridosilicatephosphates except SiPN and SiP2N4NH have been described so far.

Characterization and Decomposition of the Natural van der Waals SnSbTe under Compression.

High pressure X-ray diffraction, Raman scattering, and electrical measurements, together with theoretical calculations, which include the analysis of the topological electron density and electronic localization function, evidence the presence of an isostructural phase transition around 2 GPa, a Fermi resonance around 3.5 GPa, and a pressure-induced decomposition of SnSbTe into the high-pressure phases of its parent binary compounds (α-SbTe and SnTe) above 7 GPa. The internal polyhedral compressibility, the behavior of the Raman-active modes, the electrical behavior, and the nature of its different bonds under compression have been discussed and compared with their parent binary compounds and with related ternary materials.

Nitridophosphate-Based Ultra-Narrow-Band Blue-Emitters: Luminescence Properties of AEP N :Eu (AE=Ca, Sr, Ba).

The nitridophosphates AEP N (AE=Ca, Sr, Ba) were synthesized at 4-5 GPa and 1050-1150 °C applying a 1000 t press with multianvil apparatus, following the azide route. The crystal structures of CaP N and SrP N are isotypic. The space group Cmcm was confirmed by powder X-ray diffraction.

A Layered Tin Bismuth Selenide with Three Different Building Blocks that Account for an Extremely Large Lattice Parameter of 283 Å.

The layered compound Sn Bi Se exhibits an extraordinarily long-periodic 150R stacking sequence. The crystal structure contains three different building blocks, which form upon the addition of Sn to a Bi-rich bismuth selenide. Sn-doped Bi double ("2") layers similar to those in elemental bismuth, Sn Bi Se quintuple ("5") layers and Sn Bi Se septuple ("7") layers are arranged in a 7525757525|7525757525|7525757525 sequence, which corresponds to a structure with a=4.

BaP N NH:Eu as a Case Study-An Imidonitridophosphate Showing Luminescence.

Barium imidonitridophosphate BaP N NH was synthesized at 5 GPa and 1000 °C with a high-pressure high-temperature approach using the multianvil technique. Ba(N ) , P N and NH Cl were used as starting materials, applying a combination of azide and mineralizer routes. The structure elucidation of BaP N NH (P6 , a=7.

The Long-Periodic Loop-Branched Chain Structure of the Oxonitridophosphate La P O N , Elucidated by a Combination of TEM and Microfocused Synchrotron Radiation.

The lanthanum oxonitridophosphate La P O N was synthesized by high-pressure metathesis from partially hydrolysed LiPN and LaCl at 750-950 °C and 7-9 GPa. The combination of transmission electron microscopy (TEM) and diffraction using microfocused synchrotron radiation revealed a monoclinic crystal structure (space group P2 /n, a=14.042(4), b=7.

Reduced Local Symmetry in Lithium Compound LiSrSiO Distinguished by an Eu Spectroscopy Probe.

Research on lithium compounds has attracted much attention nowadays. However, to elucidate the precise structure of lithium compounds is a challenge, especially when considering the small ions that may be transferred between the interstitial voids. Here, the discovery of reduced local symmetry (symmetry breaking) in small domains of LiSrSiO is reported by employing Eu as a spectroscopic probe, for which X-ray, neutron, and electron diffraction have confirmed the average long-range structure with the space group 321.

Structure Elucidation of a Melam-Melem Adduct by a Combined Approach of Synchrotron X-ray Diffraction and DFT Calculations.

Melam-melem (1:1), an adduct compound that can be obtained from dicyandiamide in autoclave reactions at 450 °C and elevated ammonia pressure, had previously been described based on mass spectrometry and NMR spectroscopy, but only incompletely characterized. The crystal structure of this compound has now been elucidated by means of synchrotron microfocus diffraction and subsequent quantum-chemical structure optimization applying DFT methods. The structure was refined in triclinic space group P based on X-ray data.