. 2021 May 25;12:3097. doi: 10.1038/s41467-021-23339-x

Table 3.

Selection of top predicted reaction pathways to Fe₂SiS₄.

Path	Total cost	Reactions	ΔG_rxn (eV/atom)	Cost
1	0.177	0.6667 FeSi₂ + 3.333 S → SiS₂ + 0.3333 Fe₂SiS₄	−0.787	0.129
		5 S + Fe₃Si → Fe₂SiS₄ + FeS	−0.586	0.156
		0.4286 Fe₅Si₃ + 4 S → Fe₂SiS₄ + 0.1429 FeSi₂	−0.543	0.162
		SiS₂ + 2FeS → Fe₂SiS₄	0.270	0.335
2	0.177	0.6667 FeSi₂ + 3.333 S → SiS₂ + 0.3333 Fe₂SiS₄	−0.787	0.129
		5 S + Fe₃Si → Fe₂SiS₄ + FeS	−0.586	0.156
		S + 0.4 Fe₃Si → FeS + 0.2 FeSi₂	−0.545	0.162
		0.4286 Fe₅Si₃ + 4 S → Fe₂SiS₄ + 0.1429 FeSi₂	−0.543	0.162
		SiS₂ + 2 FeS → Fe₂SiS₄	0.270	0.335
3	0.179	0.6667 FeSi₂ + 3.333 S → SiS₂ + 0.3333 Fe₂SiS₄	−0.787	0.129
		2 FeSi + 6 S → SiS₂ + Fe₂SiS₄	−0.632	0.149
		5 S + Fe₃Si → Fe₂SiS₄ + FeS	−0.586	0.156
		0.4286 Fe₅Si₃ + 4 S → Fe₂SiS₄ + 0.1429 FeSi₂	−0.543	0.162
		S + 0.5 Fe₃Si → FeS + 0.5 FeSi	−0.509	0.167
		SiS₂ + 2 FeS → Fe₂SiS₄	0.270	0.335
4	0.180	0.6667 FeSi₂ + 3.333 S → SiS₂ + 0.3333 Fe₂SiS₄	−0.787	0.129
		2 FeSi + 6 S → SiS₂ + Fe₂SiS₄	−0.632	0.149
		5 S + Fe₃Si → Fe₂SiS₄ + FeS	−0.586	0.156
		0.4286 Fe₅Si₃ + 4 S → Fe₂SiS₄ + 0.1429 FeSi₂	−0.543	0.162
		0.5 Fe₅Si₃ + 4 S → Fe₂SiS₄ + 0.5 FeSi	−0.521	0.166
		SiS₂ + 2 FeS → Fe₂SiS₄	0.270	0.335
14	0.189	2 S + 0.5 Fe₃Si → FeS₂ + 0.5 FeSi	−0.635	0.149
		2 FeSi + 6 S → SiS₂ + Fe₂SiS₄	−0.632	0.149
		5 S + Fe₃Si → Fe₂SiS₄ + FeS	−0.586	0.156
		2 Fe₅Si₃ + 20 S → Si + 5 Fe₂SiS₄	−0.541	0.163
		Si + 2 FeS₂ → Fe₂SiS₄	0.055	0.278
		SiS₂ + 2 FeS → Fe₂SiS₄	0.270	0.335

Each pathway successfully includes the experimentally observed reaction between intermediates SiS₂ and FeS. The observed FeSi intermediate only appears together with the other two intermediates in 4 of the 49 predicted paths. Path 14 is the lowest cost path which captures all experimentally observed intermediate phases.