Table 1. Calculated and Experimental Structural and 17O NMR Parameters (Computed Ni–O Bond Lengths, Experimental Isotropic Chemical Shifts δiso,exptl, Calculated Fermi Contact Shifts δFC,calcd, and Quadrupolar Coupling Constants CQ) for La2NiO4+δ at Room Temperaturea.
|
CQ (MHz) |
|||||
|---|---|---|---|---|---|
| Ni–O dist. (Å) | δiso,exptl (ppm) | δFC,calcd (ppm) | exptl | calcd | |
| Oeq | ∼1.9 (avg) | ∼6500; 6860 (6) (MATPASS) | 10 322 | ≥4.6 | 4.73 |
| Oax | ∼2.2 (avg) | ∼3500 | 3539 (avg) | <4.6 | 1.14 (avg) |
| Oax,0 | –b | 5590 (5) | –b | <4.6 | –b |
| Oax,1 | 2.13 | 4775 (4) | 3914 | <4.6 | 2.35 |
| Oax,2 | 2.16 | 4315 (3) | 3821 | <4.6 | 1.09 |
| Oax,3 | 2.24 | 3960 (3) | 3234 | <4.6 | 0.67 |
| Oax,4 | 2.26 | 3640 (2) | 3189 | <4.6 | 0.46 |
| Oi | –c | 532 (1) | 19 | <4.6 | 0.38 |
a
Standard errors in the fitted experimental shifts are given in parentheses.
b
Not observed in DFT-optimized supercell.
c
Not bonded to Ni.