Correction to: Novel green sulfated phosphotungstic acid supported on MCM-41-coated NiFe2O4 MNPs for xanthene and coumarin synthesis (Journal of Sol-Gel Science and Technology, (2024), 109, 2, (594-610), 10.1007/s10971-022-05966-y)

Correction to: Journal of Sol-Gel Science and Technology The original version of this article unfortunately contained a mistake. The authors would like to correct the errors as given below: Figure 5 has 7 figures about xps (Fig. 5 High-resolution XPS of the prepared magnetic nanoparticles), the published manuscript divided the figures of Figure 5 into two figures and this is not true. Figure 6 has only one figure (Fig. 6 The saturation magnetization values for the magnetic nanoparticles) must take the place of Figure 7. Figure 7 has three figures (Fig. 7 Nonaqueous potentiometric titration for (A) 5-50S-10W/NF MCM-41 MNPs calcined at 450 °C, (B) MCM-41 calcined at 550 °C and different supported MCM-41 MNPs calcined at 450 °C, and (C) 20-10W/NF-MCM-41 MNPs calcined at different temperatures) must take the place of Figure 8. Fig. 8 has three figures and must take the place of Figure 9 (Fig. 8 FTIR spectra of pyridine adsorbed on (A) S-10W/NF-MCM-41 MNPs calcined at 450 °C, (B) 20-10W/NF-MCM-41 MNPs calcined at different temperatures, and (C) different supported MCM-41 MNPs calcined at 450 °C). Fig. 9 has two figures and must take the place of Fig. 10 (Fig. 9 The effect of total number of acid sites, Ei, B/L ratio, A sulfate content, and B calcination temperatures on xanthene synthesis). Fig. 10 has only one Figure and must take the place of Figure 11 (Fig. 10 Reuse of 20S-10W/NF-MCM-41-II MNP in xanthene synthesis). Fig. 11 has two figures and must take the place of Fig. 12 (Fig. 11.The effect of the total number of acid sites, Ei, B/L ratio, A sulfate content, and B calcination temperatures on coumarin synthesis). Fig. 12 has only one Figure and it is not present in the published manuscript. Figure 5 has 7 figures about xps (Fig. 5 High-resolution XPS of the prepared magnetic nanoparticles), the published manuscript divided the figures of Figure 5 into two figures and this is not true. Figure 6 has only one figure (Fig. 6 The saturation magnetization values for the magnetic nanoparticles) must take the place of Figure 7. Figure 7 has three figures (Fig. 7 Nonaqueous potentiometric titration for (A) 5-50S-10W/NF MCM-41 MNPs calcined at 450 °C, (B) MCM-41 calcined at 550 °C and different supported MCM-41 MNPs calcined at 450 °C, and (C) 20-10W/NF-MCM-41 MNPs calcined at different temperatures) must take the place of Figure 8. Fig. 8 has three figures and must take the place of Figure 9 (Fig. 8 FTIR spectra of pyridine adsorbed on (A) S-10W/NF-MCM-41 MNPs calcined at 450 °C, (B) 20-10W/NF-MCM-41 MNPs calcined at different temperatures, and (C) different supported MCM-41 MNPs calcined at 450 °C). Fig. 9 has two figures and must take the place of Fig. 10 (Fig. 9 The effect of total number of acid sites, Ei, B/L ratio, A sulfate content, and B calcination temperatures on xanthene synthesis). Fig. 10 has only one Figure and must take the place of Figure 11 (Fig. 10 Reuse of 20S-10W/NF-MCM-41-II MNP in xanthene synthesis). Fig. 11 has two figures and must take the place of Fig. 12 (Fig. 11.The effect of the total number of acid sites, Ei, B/L ratio, A sulfate content, and B calcination temperatures on coumarin synthesis). Fig. 12 has only one Figure and it is not present in the published manuscript. The correct figures are given below. High-resolution XPS of the prepared magnetic nanoparticles The saturation magnetization values for the magnetic nanoparticles. Nonaqueous potentiometric titration for (A) 5-50S-10W/NFMCM- 41 MNPs calcined at 450 °C, (B) MCM-41 calcined at 550 °C and different supported MCM-41 MNPs calcined at 450 °C, and (C) 20-10W/NF-MCM-41 MNPs calcined at different temperatures FTIR spectra of pyridine adsorbed on (A) S-10W/NF-MCM-41 MNPs calcined at 450 °C, (B) 20-10W/NF-MCM-41 MNPs calcined at different temperatures, and (C) different supported MCM-41 MNPs calcined at 450 °C The effect of total number of acid sites, E_i, B/L ratio, A sulfate content, and B calcination temperatures on xanthene synthesis Reuse of 20S-10W/NF-MCM-41-II MNP in xanthene synthesis The effect of the total number of acid sites, E_i, B/L ratio, A sulfate content, and B calcination temperatures on coumarin synthesis Reuse of 20S-10W/NF-MCM-41-II catalyst in coumarin synthesis The original article has been corrected.