Extending interstitial tetrelides into carbides: synthesis and crystal and electronic structures- of RE2Co2AlC (RE = La, Pr, Nd)

New quaternary compounds RE2Co2AlC (RE = La, Pr, Nd) of the filled W2CoB2 structure type were synthesized by the reaction of samples with the nominal composition RE40Co40Al20 (RE = La, Pr, Nd) and carbon. Single crystal X-ray diffraction data show that the RE2Co2AlC compounds crystallize in a body-centered orthorhombic space group Immm (oI12) with Z = 2 and a = 4.1841(11) Å, b = 6.1161(15) Å, c = 9.091(2) Å (La2Co2AlC); a = 4.1290(9) Å, b = 6.1152(18) Å, c = 8.844(3) Å (Pr2Co2AlC); a = 4.1168(15) Å, b = 6.1131(17) Å, c = 8.792(5) Å (Nd2Co2AlC) and are isotypic to the recently reported Nd2Co2SiC. The structures can be described as interstitial carbides of the W2CoB2 structure type with carbon atoms fully occupying the octahedral voids, which leads to the anisotropic expansion of the unit cell, more pronounced along the b-axis. Electronic structure calculations predict the RE2Co2AlC (RE = La, Pr, Nd) compounds to be metallic. The relative stability of the La2Co2AlX structures where X = C, O, Si, or a vacancy was investigated based on the bonding analysis, which emphasizes the important role that carbon plays in stabilizing the structural motif.

Merging the AuCu3- and BaAl4-based structure motifs: flux-assisted synthesis, crystal, and electronic structure of Ca2Pt7XP4-δ phosphide platinides (X = Al, Ti, and Zn)

Three quaternary phosphide platinides, Ca₂Pt₇AlP_3.00(4), Ca₂Pt₇TiP_3.24(4), and Ca₂Pt₇ZnP_2.78(2), were synthesized by a high-temperature technique using lead as a flux. According to the single-crystal diffraction data, they are isotypic and crystallize in the tetragonal space group I4/mmm with Z = 2 (Ca₂Pt₇AlP_3.00(4): a = 3.9893(6) Å, c = 26.832(5) Å; Ca₂Pt₇TiP_3.24(4): a = 3.99610(10) Å, c = 26.9074(17) Å; Ca₂Pt₇ZnP_2.78(2): a = 4.0020(2) Å, c = 26.5549(17) Å) and thus represent first europium-free compounds of the Eu₂Pt₇AlP_2.95 structure type. Their structures can be described as an intergrowth of the AuCu₃- and CaBe₂Ge₂-type blocks. DFT calculations predict metallic conductivity and non-magnetic state for all three compounds. Bonding analysis based on the Bader charge distribution and ELF topology reveals a combination of localized covalent and ionic interactions in the CaBe₂Ge₂-type fragments and complex pattern of pairwise, multi-center, and ionic interactions in the AuCu₃-type fragments that closely reproduces bonding in the parent Pt₃X (X = Al, Ti, Zn) binary intermetallics.

Metal-Rich Phosphides Obtained from the Lead Flux: Synthesis, Crystal, and Electronic Structure of Sr5Pt12P9 and BaPt3P2

Using a high-temperature ampoule technique and lead metal as a flux, we have grown single crystals and determined crystal structures from single-crystal X-ray diffraction data of two metal-rich phosphides, Sr₅Pt₁₂P₉ (P 2₁/m, a = 6.1472(3) Å, b = 25.1713(13) Å, c = 6.4635(3) Å, β = 99.604(2)°, Z = 2, R₁ = 0.0326, wR₂ = 0.0786) and BaPt₃P₂ (P 2₁2₁2₁, a = 6.3605(6) Å, b = 6.8541(7) Å, c = 11.3493(12) Å, Z = 4, R₁ = 0.0231, wR₂ = 0.0501). Both compounds belong to their own structure types and feature 3D networks of Pt and P atoms, with the channels occupied by alkaline earth metal cations. Density functional theory calculations reveal Sr₅Pt₁₂P₉ to be a metal, while BaPt₃P₂ is a narrow-gap semiconductor with a band gap of 0.24 eV. Bonding analysis shows that both compounds feature networks of prominent covalent localized Pt-P bonds, responsible for their structural stability, as well as additional weaker and, likely, less localized Pt-Pt interactions.

[Fetal inflammatory response in the development of multiple organ dysfunction in newborn]

The fetal inflammatory response syndrome (FIRS) is one of the causes of multiple organ dysfunction (MOD) in critically ill newborn infants. The paper shows a role of interleukin-8 (IL-8) in the development of FIRS and MOD in neonates a correlation between the concentration of IL-8 and the number of organs involved in the pathological process and demonstrates the leading role of endothelial dysfunction in the pathogenesis of the pathological processes concerned.