Here we use density functional theory calculations to study the impact of various spin configurations of magnetic ions on structure and properties of BiFeO3 (BFO). Low-spin and intermediate-spin electronic configurations of Fe in tetragonal BFO impact on the c/a ratio according to the way the t2g/eg orbitals are filled. Such metastable structures could enhance the magnetization in BFO and couple the ferroelectric and magnetic degrees of freedom in novel ways.
