
TY  - JOUR
A1  - Brasch, NE 
A1  - Buckingham, DA 
A1  - Clark, CR 
A1  - Rowan, AE 
T1  - <sup>17</sup>O N.M.R. Line Broadening and T<sub>1</sub>, T<sub>2</sub> Measurements on CrO<sub>4</sub><sup>2-</sup> and HCrO<sub>4</sub><sup>-</sup>
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1996
VL  - 49
IS  - 6
SP  - 697
EP  - 700
KW  - 
UR  - https://doi.org/10.1071/CH9960697 
N2  - The increase in the line width of the 17O signal of CrO42- (&#916;vCrO42- = 11±2 Hz) on adding acid is attributed to a much broader HCrO4- signal &#916;vHCrO4). This broadening is shown to have acid-independent (&#916;v0 = 67±5 Hz) and acid-dependent [&#916;v1 = (1.0±0.1) &#215; 108 Hz M-1] contributions. Direct T1 and T2 measurements give T1 &#8776; 70 ms, T2 &#8776; 40 ms for CrO42- with the difference being attributed to spin coupling (T2' = 90 ms). For HCrO4- T1 = 8±3 ms, and the acid- catalysed &#916;v1 contribution is attributed to rapid exchange of H,+ in H2CrO4 (k &#8776; 1&#215;109 s-1) showing that spin exchange effects are important for this ion. 
ER  -

