Structural and vibrational properties of Ca2FeH6 and Sr2RuH6

The structural and vibrational properties of the isostructural compounds Ca2FeH6 and Sr2RuH6 are determined by periodic DFT calculations and compared with their previously published experimental crystal structures as well as new experimental vibrational data. The analysis of the vibrational data is extended to the whole series of alkaline-earth iron and ruthenium hydrides A2TH6 (A=Mg, Ca, Sr; T=Fe, Ru) in order to identify correlations between selected frequencies and the T–H bond length. The bulk moduli of Ca2FeH6 and Sr2RuH6 have also been determined within DFT. Their calculated values prove to compare well with the experimental values reported for Mg2FeH6 and several other compounds of this structure.

Research highlights
► The first vibrational spectra for Ca2FeH6 and Ca2FeD6 are reported.
► Periodic DFT calculations show good agreement with experimental structure and spectra.
► Theoretical and experimental bulk moduli in this family of compounds are compared.