The authors learned of an error in the 183W NMR chemical shifts for compound I reported in the manuscript. The values listed (see below) were incorrect because of an error in the calibration of the spectrum. New measurements were carefully carried out to obtain a 183W NMR spectrum for compound I using a JEOL JNM ECA-500 spectrometer (183W, 20.63 MHz), and the correct chemical shifts are given below. Although these errors do not affect the main discussion and conclusion of the results, the 183W NMR chemical shifts are important data for the characterization of the polyoxometalates. The authors sincerely apologize for any inconvenience caused. The corrected text in the manuscript should read as follows: p. 5947, left column, line 47: The 183W NMR spectrum showed three signals at δ=−96.1, −109.7, and −131.5 ppm with the respective ratio of 1:1:1, which suggests that the overall symmetry of the anion is C3. p. 5949, Table 2: The 183W NMR chemical shifts for compound I (−151.3, −169.9, and −190.7 ppm) should be replaced with the new values (−96.1, −109.7, and −131.5 ppm). p. 5949, right column, line 42: NMR spectra were recorded using a JEOL JNM EX-270 or JNM ECA-500 spectrometer (1H, 269.60 or 495.13 MHz; 29Si, 53.45 or 98.37 MHz; 31P, 109.05 MHz; 183W, 11.20, 20.63, or 20.84 MHz) by using 5 mm (for 1H and 29Si (98.37 MHz)) or 10 mm (for 29Si (53.45 MHz), 31P, and 183W) tubes. p. 5950, right column, line 26: 29Si NMR (53.45 MHz, [D6]DMSO, 298 K, SiMe4): δ=−83.17 ppm (Δν1/2=3.4 Hz); 183W NMR (20.63 MHz, [D6]DMSO, 298 K, Na2WO4): δ=−96.1 (Δν1/2=22.2 Hz), −109.7 (Δν1/2=26.6 Hz), −131.5 ppm (Δν1/2=34.1 Hz) with the respective integrated intensity ratio of 1:1:1.