The understanding of structure and bonding in intermetallic phases still lags behind that of molecular compounds. For that reason, exploring intermetallic phases and identifying structural patterns and relationships are particularly important for closing this knowledge gap. In particular, here we report on the addition of increasing amounts of platinum to ∼2:1 mixtures of tin and neodymium, which yields eight ternary Pt/Sn/Nd compounds, four of which have not been reported before. Interestingly, except for PtSnNd (1), all observed ternary phases of the system can be derived from the binary compounds Sn2Nd and Sn5Nd2 by adding Pt to the composition(s), as they lie on or close to two lines: Sn2Nd-Pt (Pt0.21(1)Sn2Nd (2), PtSn2Nd (3), Pt1.33Sn2Nd (4), Pt2-xSn2+xNd (x = 0.27(3), 5), and Pt3Sn2Nd (6)) or Sn5Nd2-Pt (Pt1.5Sn5-xNd2 (x = 0.16(2), 7) and Pt3Sn5Nd2-x (x = 0.161(8), 8)). While the introduction of increasing amounts of Pt to the binaries Sn2Nd and Sn5Nd2 leads to stepwise changes in the coordination environment of Nd, Pt preserves its coordination over the entire system in the form of interpenetrating bipyramidal {PtSn5Nd5} clusters.

A multi-gram synthetic route to black solid {CSc₆}I₁₂Sc (1) was developed which comprises the reaction of scandium triiodide, ScI₃, with graphite and scandium metal at 850°C. Compound 1 dissolved in N,N-dimethylacetamide (DMA) to form a red solution. Results derived from ⁴⁵Sc NMR and EPR spectroscopy indicated that a scandium cluster species exists in this solution along with a complex cation [Sc(DMA)₆]³⁺. From these solutions crystals of [Sc(DMA)₆]I₃ (2) and a red oily product was isolated. Compound 2 was also prepared independently by dissolving ScI₃ in DMA and two polymorphs, orthorhombic 2O and monoclinic 2M were crystallised. {CSc₆}I₁₂Sc (1) also dissolved in THF yielding a red solution which contains [ScI₆]³⁻ and a scandium cluster species, as analysed by ⁴⁵Sc NMR and EPR spectroscopy.

Although rare-earth-metal-transition-metal (R/T) phase diagrams have been explored extensively, our recent studies have uncovered new previously nonexistent binary intermetallics. These compounds belong to a narrow region between 70 and 71.4 atom % of the rare-earth metal but represent four different structure types. The binaries Tb7Pd3 and Er17Pd7 are compositionally approaching (less than 1 atom % difference) the previously reported R2.16Pd0.89 (R = Tb and Er), and apparently form by peritectoid transformation, thus, being hard to detect by fast cooling. Tb7Pd3 (1) crystallizes in the Th7Fe3 structure type (hP20, P6(3)mc, a = 9.8846(4) angstrom, c = 6.2316(3) angstrom, Z = 2) while Er17Pd7 (2) belongs to the Pr17Co7 type being its second reported representative (cP96, P2(1)3, a = 13.365(2) degrees, Z = 4). Er17Pd7 (2) is overlapping with the cubic F-centered Er2.11Pd0.89 (3b, Fd (3) over barm, a = 13.361(1) angstrom, Z = 32) with practically identical unit cell parameters but a significantly different structure. Electronic structure calculations confirm that heteroatomic R-T bonding strongly dominates in all structures; T-T bonding interactions are individually strong but do not play a significant role in the total bonding.

Isonicotine amide, picoline amide, pyrazine 2-amide, 2- and 4-amino benzamides and various Cu-II salts were used to target Cu-II complexes of these ligands alongside with 1D and 2D coordination polymers. Under the criterion of obtaining crystalline and single phased materials a number of new compounds were reliably reproduced. Remarkably, for some of these compounds the ideal Cu:ligand ratio of the starting materials turned out to be very different from Cu:ligand ratio in the products. Crystal and molecular structures from single-crystal XRD were obtained for all new compounds; phase purity was checked using powder XRD. We observed exclusively the O-amide and not the NH2amide function binding to Cu-II. In most of the cases; this occurred in chelates with the second pyridine, pyrazine or aminophenyl N function. mu-O,N ditopic bridging was frequently observed for the N = pyridine, pyrazine or aminophenyl functions, but not exclusively. The geometry around Cu-II in these compounds was very often axially elongated octahedral or square pyramidal. X-band EPR spectra of powder samples revealed various spectral symmetry patterns ranging from axial over rhombic to inverse axial. Although the EPR spectra cannot be unequivocally correlated to the observed geometry of Cu-II in the solid state structures, the EPR patterns can help to support assumed structures as shown for the compound [Cu(Ina)(2)Br-2] (Ina = isonicotine amide). As UV-vis absorption spectroscopy and magnetic measurement in the solid can also be roughly correlated to the surrounding of Cu-II, we suggest the combination of EPR, UV-vis spectroscopy and magnetic measurements to elucidate possible structures of Cu-II compounds with such ligands.

The rare-earth elements in the divalent state, i.e. with oxidation number + 2, may either have the electron configuration 4f(n+1)5d degrees(symbolized as R2+) or 4f(n)5d(1) (R(3+)e(-)). As R2+ (R = Eu, Yb, Sm, Tm, Dy, Nd) they can either be contained in extended solids as in the insulating diiodides RI2, or in coordination complexes such as samarocene, Kagan's reagent, or TmI2(DME)(3). In the case of R(3+)e(-), the "excess" d electron can either be delocalized and cause (semi)metallic behavior in extended solids, e.g. in LaI2, or localized with the R(3+)e(-) = 4f(n)5d(1) ion trapped in a coordination complex with (super)bulky ligands such as in [K(2.2.2-crypt)][LaCp ''(3)]. Thus, the seemingly small cause of a one-electron configuration crossover, 4f(n+1)5d degrees <--> Hf(n)5d(1) has a large effect on the chemical behavior and physical properties of the respective compounds where atomic properties and ligand effects play important roles.