Lattice parameters, Wyckoff sites, atomic fractional coordinates, occupancies, and isotropic temperature factors of the room temperature structures for A \mathrm{Ln}_{2} \mathrm{CuTi}_{2} \mathrm{O}_{9}(A=\mathrm{Ca}, \mathrm{Ba}; \mathrm{Ln}=\mathrm{La}, \mathrm{Pr}, \mathrm{Nd}, \mathrm{Sm}) obtained from XRPD patter refinements.* fixed in 0.5 \AA to guarantee the convergence of the refinement.
| Atom | Site | x | y | z | Occupancy | \mathrm{B}_{\text {iso }}\left(\AA^{2}\right) |
|---|---|---|---|---|---|---|
| \mathrm{CaPr}_{2} \mathrm{CuTi}_{2} \mathrm{O}_{9} | ||||||
| Pbnm; a=5.4821(1) \AA, b=5.5942(1) \AA, c=7.6869(1) \AA, R_{\mathrm{p}}=16.4 \%, R_{\mathrm{wp}}=23.6 \%, \chi^{2}=1.74, R_{\text {Bragg }}=8.34 \% | ||||||
| Ca/Pr | 4 c | -0.0069(5) | -0.0452(3) | 0.75 | 0.35/0.65 | 0.34(5) |
| Cu/Ti | 4 b | 0.5 | 0 | 0 | 0.35/0.65 | 0.5* |
| O1 | 4 c | 0.423(3) | 0.019(2) | 0.75 | 1 | 0.7(2) |
| O2 | 8 d | 0.203(2) | 0.789(2) | 0.459(1) | 1 | 0.7(2) |
| \mathrm{CaNd}_{2} \mathrm{CuTi}_{2} \mathrm{O}_{9} | ||||||
| Pbnm; a=5.4557(1) \AA, b=5.5769(1) \AA, c=7.6594(2) \AA, R_{\mathrm{p}}=18.0 \%, R_{\mathrm{wp}}=26.0 \%, \chi^{2}=2.12, R_{\text {Bragg }}=9.77 \% | ||||||
| Ca/Nd | 4 c | -0.0079(6) | -0.0467(4) | 0.75 | 0.35/0.65 | 0.70(6) |
| Cu/Ti | 4 b | 0.5 | 0 | 0 | 0.35/0.65 | 0.5* |
| O1 | 4 c | 0.423(3) | 0.020(3) | 0.75 | 1 | 1.5(3) |
| O2 | 8 d | 0.202(2) | 0.790(2) | 0.458(2) | 1 | 1.5(3) |
| \mathrm{CaSm}_{2} \mathrm{CuTi}_{2} \mathrm{O}_{9} | ||||||
| Pbnm; a=5.4221(2) \AA, b=5.6097(2) \AA, c=7.6129(3) \AA, R_{\mathrm{p}}=20.5 \%, R_{\mathrm{wp}}=27.8 \%, \chi^{2}=2.43, R_{\mathrm{Bragg}}=12.1 \% | ||||||
| Ca/Sm | 4 c | -0.0109(6) | -0.0558(4) | 0.75 | 0.35/0.65 | 0.84(7) |
| Cu/Ti | 4 b | 0.5 | 0 | 0 | 0.35/0.65 | 0.5^{*} |
| O1 | 4 c | 0.406(4) | 0.033(3) | 0.75 | 1 | 1.5(3) |
| O2 | 8 d | 0.197(3) | 0.797(3) | 0.456(2) | 1 | 1.5(3) |
| \mathrm{BaLa}_{2} \mathrm{CuTi}_{2} \mathrm{O}_{9} | ||||||
| I4/mcm; a=5.6032(2) \AA, c=7.9192(6) \AA, R_{\mathrm{p}}=14.2 \%, R_{\mathrm{wp}}=22.6 \%, \chi^{2}=1.99, R_{\mathrm{Bragg}}=3.65 \% | ||||||
| Ba/La | 4 b | 0 | 0.5 | 0.25 | 0.35/0.65 | 2.32(7) |
| Cu/Ti | 4 c | 0 | 0 | 0 | 0.35/0.65 | 1.8(1) |
| O1 | 4 a | 0 | 0 | 0.25 | 1 | 5.4(4) |
| O2 | 8 h | 0.268(4) | 0.232(4) | 0 | 1 | 5.4(4) |
| \mathrm{BaPr}_{2} \mathrm{CuTi}_{2} \mathrm{O}_{9} | ||||||
| I4/mcm; a=5.5837(2) \AA, c=7.8882(5) \AA, R_{\mathrm{p}}=17.0 \%, R_{\mathrm{wp}}=27.0 \%, \chi^{2}=2.80, R_{\mathrm{Bragg}}=3.84 \% | ||||||
| Ba/Pr | 4 b | 0 | 0.5 | 0.25 | 0.35/0.65 | 2.64(9) |
| Cu/Ti | 4 c | 0 | 0 | 0 | 0.35/0.65 | 2.0(2) |
| O1 | 4 a | 0 | 0 | 0.25 | 1 | 6.6(6) |
| O2 | 8 h | 0.275(5) | 0.225(5) | 0 | 1 | 6.6(6) |
| \mathrm{BaNd}_{2} \mathrm{CuTi}_{2} \mathrm{O}_{9} | ||||||
| I4/mcm; a=5.5773(2) \AA, c=7.8743(5) \AA, R_{\mathrm{p}}=17.5 \%, R_{\mathrm{wp}}=25.9 \%, \chi^{2}=2.08, R_{\mathrm{Bragg}}=6.62 \% | ||||||
| Ba/Nd | 4 b | 0 | 0.5 | 0.25 | 0.35/0.65 | 1.5(1) |
| Cu/Ti | 4 c | 0 | 0 | 0 | 0.35/0.65 | 0.5* |
| O1 | 4 a | 0 | 0 | 0.25 | 1 | 5.8(6) |
| O2 | 8 h | 0.273(6) | 0.227(6) | 0 | 1 | 5.8(6) |