电弧熔炼方法合成了Hf2＋XMO3-XSI4（X＝0.3），单晶X射线衍射方法测定了晶体结构.化学式，Hf2.3（2）MO2.7（2）SI4，Mr＝781.9，晶体学及结构参数：正交晶系，CE2SC3SI4类型，（62）PnMA，A＝0.6579（1），b＝1.2818（4），C＝0.6778（1）nM，V＝0.5716（1）nM3，z＝4，dX＝9.084g/CM3，μ＝501.55CM-1（λMOkα＝0.07107nM），f（000）＝1340，T＝296k，对于25个修正参数和637个独立可观察衍射点r＝0.075，Wr＝0.068.此结构中，SI原子两两成键联接成哑铃状，MO原子均处于SI原子所形成的配位畸变八面体中心，这些配位八面体最终联接形成三维MO-SI网络，Hf原子则散布在网络之间沿［100］方向的隧道中.此化合物组成和结构不符合价键规律，成键具有过渡性且原子的配位环境遵守此类化合物规律.Hf 2+x Mo 3-x Si 4 (x=0.3) was synthesized by arcmelting method and its crystal structure was characterized by single crystal XRD method.Crystallographic and refined structure parameters are: formula, Hf 2.3(2) Mo 2.7(2) Si 4 , Mr =781.9, orthorhombic,Ce 2Sc 3Si 4 type,(62) Pnma, a =0.657 9(1), b =1.281 8(4) , c =0.677 8(1) nm, V =0.571 6(1) nm 3, Z =4, D x =9.08 4 g/cm 3, μ =501.55 cm -1 ( λ MoKα=0.07107 nm), F (000)=134 0, T =296 K, R =0.075 and wR= 0.068 for 25 refined parameters and 637 contributing independent observed reflections.The structure is characterized by bonded Si-Si dumbbells.The Mo atoms are coordinated by deformed Si octahedra which form three dimensional net by connection.The Hf atoms are distributed in tunnels along direction.The compound is not a valence compound since bonds have typical transitional features.General coordination environment rules are followed.国家自然科学青年基金;国家教委优秀年青教师基
