Table 9. A priori bond valences (v.u.) for NaFe³⁺Si₂O₆ .

	Na	Fe	Si	∑
O1	0.113 ×2↓	0.45 ×4↓ ×2→	0.988	2
O2	0.263 ×2↓	0.6 ×2↓	1.138	2
O3	0.062 ×4↓ ×2→		0.938 ×2↓ ×2→	2
∑	1	3	4