结晶





Disambig gray.svg  本文介紹的是結晶過程。關於結晶過程凝出的固體，請見「晶體」。



結晶的蜂蜜


结晶，是指从饱和溶液中凝結，或從氣體凝華出具有一定的几何形状的固体（晶體）的过程。在自然環境下，氣溫的下降壓力的作用，都會造成結晶。結晶的過程一般可分為兩個階段（包括成核和晶體生長期），时间也有所不同。


結晶亦是一種分離固態和液態物質的技術，其中溶質由溶液中轉移至純淨的晶體裡。不少自然過程都涉及結晶:



  • 天然晶體的形成 （如礦物、寶石等）


  • 雪花的形成

  • 蜂蜜的結晶


如饱和溶液的氣溫下降速度慢，會形成一顆較大的晶體；如氣溫急劇下降，會形成粉狀的小晶體。而小晶體可以放進饱和溶液充當大晶體的種子。
而重結晶或再結晶是重複結晶作用，用以準備純度更高的結晶。



人工形成


結晶過程只能在過飽和和飽和溶液裡發生。晶體可藉由冷卻過飽和溶液後結晶所得。在工業上，改變溶液的pH值也是常見的結晶方法。



參見



  • 重結晶

  • 晶體學


























  • 查

  • 论

  • 编


不对称合成

命名


  • 手性

  • 立体中心

  • 立体异构

  • 对映异构体

  • 非对映异构体

  • 内消旋化合物

  • 平面手性（英语：Planar chirality）

  • 手性配体

  • 轴手性
分析


  • 旋光性

  • 对映体过量百分数

  • 非对映体过量

  • 手性拆分试剂
拆分


  • 重结晶

  • 动力学拆分（英语：Kinetic resolution）

  • 手性色谱法
反应


  • 不对称诱导

  • 手性库合成

  • 手性辅助剂

  • 不对称催化还原反应

  • 不对称催化氧化反应

  • 有机催化

  • 生物催化



















































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