甲烷水合物6(H2O)4分子14面体(4668)笼型结构

Tetrakaidecahedron(4668)cage of 6(H2O)4 molecule of methane clathrate

对于水分子和水分子簇结构的再认识,以杂化轨道理论为基础,按照H2O分子中O原子发生p^3s不等性杂化(2p^43s^0→(p^3s)2(p^3s)1(p^3s)1(p3s)0)的观点,认为H2O分子的O原子价层里既有1个含有1对电子的非键轨道,又有1个非键空轨道。在此基础上,提出了水分子簇的(H2O)4分子是由单体H2O分子之间通过3c-2e(3原子、2电子)的O-H-O氢桥键形成的氢桥环结构;由(H2O)4分子彼此之间通过氢键连接成的6(H2O)414面体(4^66^8)型分子笼、5(H2O)4分子10面体(4^56^412^1)型分子笼是甲烷水合物晶体里的2种水分子笼构型。

Based on the theory of hybrid orbital,the water molecules and water clusters were structurally understood.According to the viewpoint that the O atoms in H2O molecules underwent p3 sunequal-property hybridization(2p43s0→(p3s)2(p3s)1(p3s)1(p3s)0),it was believed that the valence shell of O atoms in H2O molecules had one nonbonding orbital occupying one pair of electrons and one nonbonding empty orbital.It was proposed accordingly that the water cluster(H2O)4 wasthe hydrogen bridge ring structure formed by O-H-O hydrogen bridge bonds of 3c-2e(three atoms and two electrons)between H2O molecules.Both the tetrakaidecahedron(4668)molecular cageconsisting of six(H2O)4 molecules connected by hydrogen bonds and the decahedron(4564121)molecular cageconsisting of five(H2O)4 molecules connected by hydrogen bonds are two water molecule cages in the methane hydrate crystal.