Table 2. Calculated Unit Cell Parameters (Å), Unit Cell Volume (ų), Volume per Atom (ų), and Selected Bond Lengths (Å) for YSr₂Cu₂FeO₇ and YSr₂Cu₂FeO₈ Idealized Oxides^a.

YSr2FeCu2O8	experimental YSr2FeCu2O7.85	GGA	GGA + U	SCAN	YSr2FeCu2O7	experimentalb YSr2FeCu2O7.08	C-AF GGA	C-AF GGA + U	C-AF SCAN
a, b	3.8145(3)	3.8252	3.8315	3.7861	a	22.9136(5)b	23.1337	23.1424	22.8529
c	11.327(7)	11.3803	11.5457	11.2755	b	5.4577(1)b	5.5007	5.5069	5.4411
V	164.81(1)	166.52	169.50	161.62	c	5.4053(1)b	5.4241	5.4265	5.3744
V per atom	11.77	11.89	12.10	11.54	V	675.98(2)	690.13	691.63	668.22
d Fe–O3	1.9072(2)	1.9126	1.9157	1.8930	V per atom	13.00	13.27	13.30	12.85
d Fe–O1	1.843(4)	1.8550	1.8813	1.8417	mean d Fe–O	1.8732	1.8754	1.9014	1.8732
d Fe–O1/d Fe–O3	0.9663	0.9699	0.9820	0.9729	Fe–O3–Fe	124.6°	126.0°	122.9°	124.5°
d Cu–O2	1.9244(4)	1.9355	1.9473	1.9147	d Cu–O2	1.933(2)/1.934(2)	1.9365/1.9456	1.9413/1.9507	1.9267/1.9338
d Cu–O1	2.117(4)	2.1134	2.1197	2.0812	d Cu–O1	2.302(4)	2.4327	2.3883	2.3449
d Cu–O1/d Cu–O2	1.1000	1.0919	1.0885	1.0870	d Cu–O1/d Cu–O2	1.1906	1.2533	1.2273	1.2148
d Cu–Cu	3.407(4)	3.4435	3.5439	3.4297	d Cu–Cu	3.384(4)	3.2837	3.3506	3.3095
d Cu–Fe	3.960(3)	3.9684	4.0009	3.9229	d Cu–Fe	4.056(2)	4.1639	4.1337	4.0815

^aThe experimental data of YSr₂Cu₂FeO_7.86 (ICSD—11514) and YSr₂Cu₂FeO_7.08 (this work) are included for comparison. For the GGA + U method, a value of U = 4 eV is used for both Cu and Fe.

^bLattice parameters given in the setting for the S.G. Ima2. The unit cell metrics corresponding with the S.G. Imma (Table 1) is a (Imma) < > c (Ima2); b (Imma) < > a (Ima2); and c (Imma) < > b (Ima2).