At the request of the authors, the proceedings paper  will be retracted. The reason is the ethical conflict of publishing similar paper in this forum and in Crystals. We apologize to our readership for any inconvenience caused.
1 Cándida Pastor Ramírez; Sylvain Bernès; Rafael Zamorano Ulloa; Daniel Ramírez-Rosales; Samuel Hernández-Anzaldo; Yasmi Reyes-Ortega, Tetramer compound of manganese ions with mixed valence [Mn2IIMn2IV] and its spatial, electronic and magnetic studies. Proceedings of The 1st International Electronic Conference on Crystals, 1 (doi: 10.3390/IECC_2018-05245).
Retraction of the Proceedings Paper: https://sciforum.net/paper/view/conference/5245