Carbonates

Rare earth carbonates are brown in color.Light rare earth carbonates (lanthanum, cerium, , praseodymium, neodymium) are Orthocarbonate octahydrate;Some of the medium and heavy rare earth carbonates (Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Yttrium) are low hydration orthocarbonates;The carbonates of the heavy rare earths Thulium, Ytterbium, and Lutetium are alkaline salts or carbonate oxides.