Synthesis, magnetic and NMR spectroscopic properties of the MAlPt series (M = Ca, Y, La-Nd, Sm-Er).

Following recent investigation in the ternary system Sr-Al-Pt led to the discovery of SrAlPt which crystallizes in the orthorhombic YNiSi type () structure. Interestingly, only two more aluminum representatives, CeAlPt and EuAlPt, have been reported to adopt this structure type. Therefore, we decided to investigate the existence range of compounds adopting the YNiSi type structure. Besides the already known Sr, Ce and Eu members, the series could be extended to Ca, Y and La-Nd as well as Sm-Er. All compounds were synthesized from the elements and characterized by powder X-ray diffraction. While for CaAlPt and LaAlPt also the respective MAlPt members were observed, the other compounds could be obtained either as X-ray pure materials or with small amounts of AlPt as a side phase. The structure of ErAlPt could be refined from single crystal data, verifying that also the small rare-earth elements adopt the YNiSi type structure. Selected members of the series were furthermore characterized by magnetization and susceptibility measurements. Since YAlPt could be obtained as a phase pure material and exhibits no paramagnetic behaviour it was investigated by Al MAS NMR investigations. Also, XPS measurements were conducted on this compound to gain an insight into the charge distribution. Finally, quantum-chemical calculations supported the NMR measurements and gave an insight into the chemical bonding and the charge distribution.