Standard enthalpies of formation of selected Ru2YZ Heusler compounds

•Standard enthalpies of formation of Ru2YZ were measured using a drop calorimeter.•Result of L21 structured compounds agrees with first principles data.•Lattice parameters and related phase relationships were consistent with literature data.•Ru2HfSn, Ru2TiSn, Ru2VGa, Ru2VSi, Ru2VSn of L21 structure were reported for the first time.

The standard enthalpies of formation of selected ternary Ru-based Heusler compounds Ru2YZ (Y = Fe, Hf, Mn, Ti, V; Z = Al, Ga, In, Si, Ge, Sn) were measured using high temperature direct reaction calorimetry. The measured enthalpies of formation (in kJ/mole of atoms) of the Heusler compounds are, Ru2FeGe (−19.7 ± 3.3); Ru2HfSn (−24.9 ± 3.6); Ru2MnSi (−46.0 ± 2.6); Ru2MnGe (−29.7 ± 1.0); Ru2MnSn (−20.6 ± 2.4); Ru2TiSi (−94.9 ± 4.0); Ru2TiGe (−79.1 ± 3.2); Ru2TiSn (−60.6 ± 1.8); Ru2VSi (−55.9 ± 1.7);for the B2-structured compounds, Ru2FeSi (−28.5 ± 0.8); Ru2HfAl (−70.8 ± 1.9); Ru2MnAl (−32.3 ± 1.9); Ru2MnGa (−25.3 ± 3.0); Ru2TiAl (−62.7 ± 3.5); Ru2VAl (−30.9 ± 1.6); Ru2ZrAl (−64.5 ± 1.5). Values were compared with those from published first principles calculations and the OQMD (Open Quantum Materials Database). Lattice parameters of these compounds were determined using X-ray diffraction analysis (XRD). Microstructures were identified using scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS).