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Anhydrous lanthanum(III) chloride can be produced by the ammonium chloride route. [3] [4] [5] In the first step, lanthanum oxide is heated with ammonium chloride to produce the ammonium salt of the pentachloride: La 2 O 3 + 10 NH 4 Cl → 2 (NH 4) 2 LaCl 5 + 6 H 2 O + 6 NH 3
Although most compounds are referred to by their IUPAC systematic names ... Water - H 2 O [204] He ... Lanthanum(III) sulfate – La 2 (SO 4) 3; Pb
The anhydrous compound can be produced by heating the hydrates to 300 °C. If heated further, anhydrous lanthanum(III) sulfate decomposes to La 2 O 2 SO 4 at 775 °C, which in turn decomposes to lanthanum(III) oxide at 1100 °C.
These reactions can also start with the metals, e.g.: [4] Y + 5 NH 4 Cl → (NH 4) 2 YCl 5 + 1.5 H 2 + 3 NH 3 Step 2 thermolysis of ammonium lanthanide chlorides. The ammonium lanthanum chlorides are converted to the trichlorides by heating in a vacuum. Typical reaction temperatures are 350–400 °C: [4] (NH 4) 2 MCl 5 → MCl 3 + 2 HCl + 2 NH 3
Lanthanum fluoride is insoluble in water and can be used as a qualitative test for the presence of La 3+. The heavier halides are all very soluble deliquescent compounds. The anhydrous halides are produced by direct reaction of their elements, as heating the hydrates causes hydrolysis: for example, heating hydrated LaCl 3 produces LaOCl. [38]
The La 3+ metal atoms are surrounded by a 7 coordinate group of O 2− atoms, the oxygen ions are in an octahedral shape around the metal atom and there is one oxygen ion above one of the octahedral faces. [4] On the other hand, at high temperatures lanthanum oxide converts to a C-M 2 O 3 cubic crystal structure.
Some nitride is produced along with the oxide, when lanthanum metals are ignited in air. [8] Alternative methods of synthesis are a high temperature reaction of lanthanide metals with ammonia or the decomposition of lanthanide amides, Ln(NH 2) 3. Achieving pure stoichiometric compounds, and crystals with low defect density has proved difficult ...
Lanthanum(III) oxalate forms colorless crystals that are poorly soluble in water. [3] The compound forms various crystallohydrates La 2 (C 2 O 4) 3 •n H 2 O, where n = 1, 2, 3, 7, and 10. [4] [5] The crystallohydrates decompose when heated. [6]