Table 1.

X-ray powder data observed (obs.) and calculated (calc.) for NaBi₂Ta₅O₁₆ and TlBi₂Ta₅O₁₆.

	NaBi2Ta5O16			TlBi2Ta5O16
hkl	dobs. (Å)	dcalc. (Å)	I (%)	dobs. (Å)	dcalc. (Å)	I (%)
111	6.06	6.06	16	6.07	6.07	9
220	3.713	3.712	<1	3.718	3.717	1
311	3.166	3.166	11	3.170	3.170	21
222	3.0315	3.0314	100	3.0353	3.0352	100
400	2.6253	2.6253	35	2.6286	2.6286	29
331	2.4092	2.4091	1	2.4122	2.4121	1
422	2.1435	2.1436	<1	2.1463	2.1462	<1
511	2.0209	2.0210	2	2.0235	2.0235	3
440	1.8563	1.8564	41	1.8587	1.8587	38
531	1.7750	1.7750	4	1.7773	1.7772	6
442	-	1.7502	-	1.7524	1.7524	<1
620	1.6604	1.6604	<1	1.6625	1.6624	<1
533	1.6014	1.6014	1	1.6034	1.6034	4
622	1.5831	1.5831	36	1.5851	1.5851	33
444	1.5157	1.5157	10	1.5176	1.5176	9
551	1.4704	1.4705	2	1.4723	1.4723	3
731	1.3671	1.3671	3	1.3689	1.3688	4
800	1.3127	1.3127	5	1.3143	1.3143	4
733	1.2829	1.2829	<1	1.2845	1.2845	1
644	-	1.2735	-	1.2751	1.2751	<1