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 · 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

结晶 · 动力学拆分 · 手性色谱法
反应

手性诱导 · 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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