It probably represents the partial dehydration of limonite, and by further loss of water may pass into haematite or red iron ore.
Acetonyl-acetophenone, C6H5.CO.CH2.CH2.CO.CH3, is produced by condensing phenacyl bromide with sodium acetoacetate with subsequent elimination of carbon dioxide, and on dehydration gives aa-phenyl-methyl-furfurane.
Energetic dehydration gives the olefine hydrocarbons, but under certain conditions ethers (see Ether) are obtained.
Distilled with zinc dust morphine yields phenanthrene, pyridine and quinoline; dehydration gives, under certain conditions, apomorphine, C17H17N02, a white amorphous substance, readily soluble in alcohol, either and chloroform.
The carbonate, being insoluble in strong alcohol (and many other liquid organic compounds), is much used for dehydration of the corresponding aqueous preparations.
Correlatively in its process of dehydration to form plaster of Paris, monosymmetric gypsum is converted into the orthorhombic form before it begins to be dehydrated.