Figure 1

An illustration of the calculation of uniqueness values. The red peak represents the peak of interest and three peaks are in its immediate vicinity. The calculations are only performed at five chemical shifts distance levels – 0.01, 0.02, 0.03, 0.04, 0.05 ppm along the ¹H dimension, and 0.05, 0.10, 0.15, 0.20, 0.25 ppm along the ¹³C dimension. No peak is observed in the first three distance levels. So the maximum unique scope for this peak is (0.03, 0.15) ppm. Peak A is found within 0.03~0.04 ppm (¹H dimension) and 0.15~0.20 ppm (¹³C dimension) of the red peak; Peak B is found within 0.04~0.05 ppm (¹H dimension) and 0.20~0.25 ppm (¹³C dimension) of the red peak; Peak C is not considered since the chemical shift distance is more than 0.05 ppm along the ¹H dimension. Therefore, the assigned uniqueness values are 0-0-0-1-2. Note that the distance is not drawn to scale.