title: M4H4X: hydrometals (M=Cu, Ni) containing tetracoordinate planar nonmetals (X=B, C, N, O).
authors.affiliation: Institute of Materials Sciences and Department of Chemistry, Xinzhou Teachers' University, Xinzhou 034000, Shanxi, P. R. China. lisidian@yahoo.com
authors.forename: Si-Dian
authors.initials: SD
authors.lastname: Li
authors.forename: Guang-Ming
authors.initials: GM
authors.lastname: Ren
authors.forename: Chang-Qing
authors.initials: CQ
authors.lastname: Miao
authors.forename: Zhi-Hao
authors.initials: ZH
authors.lastname: Jin