(中南大學 化學化工學院， 長沙 410083)
摘 要: 研究了超聲波作用下鉬酸銨溶液的結(jié)晶過程，揭示了超聲波對四鉬酸銨晶型的影響規(guī)律。研究表明，在無超聲波作用下生成β型四鉬酸銨的反應需1～2d，在超聲波作用下只需十幾分鐘即可完成，并且發(fā)生晶型改變，生成了微粉型四鉬酸銨。在實驗基礎上提出了鉬酸銨溶液結(jié)晶的可能途徑，并在RHF/3-21G和STO-3G水平上，對超聲波作用下鉬酸銨溶液結(jié)晶過程中所涉及到的H2Mo7O4-24， H8Mo8O4-30，(MoO2)(MoO3)x-1］2+(x=1，2，3)，(NH4)4Mo8O26等進行量子化學從頭計算，得到各研究體系的總能量和集居數(shù)。計算結(jié)果表明，當pH值為2.3～2.5時，超聲波產(chǎn)生的特殊的“超聲效應”可能使鉬酸銨溶液中的H2Mo7O4-24變成［(MoO2)(MoO3)x-1］2+(x=1，2，3)，從而生成微粉型四鉬酸銨。
關(guān)鍵字: 超聲波；鉬酸銨溶液；結(jié)晶；量子化學從頭計算
molybdate solution under ultrasonic
ZHANG Ping-min，LI Jie
（College of Chemistry and Chemical Engineering,
Central South University, Changsha 410083, China）
Abstract:The crystallization process of ammonium molybdate solution under ultrasonic was studied. The crystalline under ultrasonic were detected. It is indicated that ultrasonic has a great effect on the process of preparation β-type ammonium tetramolybdate. The crystallization time is shortened from 1～2d to 10～20min under ultrasonic and the crystalline converts into microcrystal-type under ultrasonic. The total energy and condensation of atoms of H2Mo7O4-24, H8Mo8O4-30, ［MoO2)(MoO3)x-1 ］2+(x=1，2，3) and (NH4)4Mo8O26 were computed at the HF/3-21G, STO-3G level. The calculation results show that the transformation from H2Mo7O4-24 to ［(MoO2)(MoO3)x-1］2+(x=1，2，3) at pH 2.3～2.5 is the reason of crystallization of microcrystal-type under ultrasonic.
Key words: ultrasonic; ammonium molybdate solution; crystallization; abinitio
