共生晶体Mn2Hg4(SCN)12和MnHg(SCN)4的形成

采用恒温蒸发法从水溶液中生长Hg2+、Mn2+为双配位中心的SCN- 的配合物晶体.生长液中Hg2+含量较SCN-适当过量的条件下,出现Mn2Hg4(SCN)12晶体和MnHg(SCN)4晶体共生现象.MnHg (SCN)4晶体中Hg2+只与SCN-配位,Mn2+只与NCS-配位,而Mn2Hg4(SCN)12晶体中部分Hg2+可以同时与SCN-和NCS-配位体结合,并且部分SCN-同时和2个Hg2+结合成桥式结构.Mn2Hg4(SCN)12晶体中Mn2+的配位数由MnHg(SCN)4晶体中的4配位增大为5配位和6配位.Mn(NCS)4-6 和Mn(NCS)3-5 配位多面体的存在使Mn2Hg4(SCN)12晶体的颜色比MnHg(SCN)4晶体的颜色浅.

Comparison Study on the Crystal Structure of Symbiotic Compound Crystals Mn2Hg4(SCN)12 and MnHg (SCN)4

The coordination complex crystals containing two coordinate centers Hg~(2 ) and Mn~(2 ) have been synthesized from aqueous solutions by using the constant temperature evaporation method.A new crystal of Mn_2Hg_4(SCN)_(12),as a intergrowth crystal with MnHg(SCN)_4,was obtained under the condition of excessive Hg~(2 ) atoms.Hg~(2 ) in the crystal structure of MnHg(SCN)_4 is only coordinated by SCN~-ligands and Mn~(2 ) is only coordinated by NCS~-ligands,but part of Hg~(2 ) in the structure of Mn_2Hg_4(SCN)_(12) is linked by SCN~-or NCS~-ligands,and part of SCN~-is linked by two Hg~(2 ) atoms,forming a bridging structure.The coordination numbers of Mn~(2 ) in Mn_2Hg_4(SCN)_(12) are changed from four in MnHg(SCN)_4 to five and six.The existence of two coordination polyhedra: Mn(NCS)~(4-)__6 and Mn(NCS)~(3-)__5 leads to the pale colour of Mn_2Hg_4(SCN)_(12) compared with that of MnHg(SCN)_4.