Lanthanum hydroxycarbonate

General
Surname	Lanthanum hydroxycarbonate
other names	Lanthanum carbonate hydroxide
Molecular formula	LaOHCO 3
External identifiers / databases
CAS number 198017-16-2 Wikidata Q2754801
properties
Molar mass	215.92 g mol −1
Physical state	firmly
density	4.48 g cm −3
Melting point	310 ° C (decomposition)
safety instructions
GHS hazard labeling no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Lanthanum hydroxycarbonate , LaOHCO ₃ , is a chemical compound of the rare earth metal lanthanum .

presentation

Lanthanum hydroxycarbonate can be produced in the laboratory from lanthanum nitrate , ammonia and carbon dioxide in an aqueous solution.

${\displaystyle \mathrm {La(NO_{3})_{3}\ +\ 3\ NH_{4}OH\ \longrightarrow \ La(OH)_{3}\ +\ 3\ NH_{4}NO_{3}} }$

${\displaystyle \mathrm {CO_{2}\ +\ H_{2}O\ \longrightarrow \ H_{2}CO_{3}} }$

${\displaystyle \mathrm {La(OH)_{3}\ +\ H_{2}CO_{3}\ \longrightarrow \ LaOHCO_{3}\ +\ 2\ H_{2}O} }$

properties

Physical Properties

Lanthanum hydroxycarbonate occurs in an orthorhombic ( space group Pmcn (space group no. 62, position 5) ) or hexagonal crystal structure , depending on its production . It also occurs as a hydrate form, which separates the water of crystallization from 180 ° C.

Chemical properties

Differential calorimetric measurements have shown that lanthanum hydroxycarbonate decomposes in two stages when heated. First, it splits off water and CO ₂ at 430 ° C (another source from 310 ° C) , producing lanthanum oxide carbonate:

${\displaystyle \mathrm {2\ LaOHCO_{3}\ \longrightarrow \ La_{2}O_{2}CO_{3}\ +\ H_{2}O\ +\ CO_{2}} }$

If the temperature is increased to 500 ° C (other source 800 ° C), further separation of carbon dioxide takes place with the formation of lanthanum oxide :

${\displaystyle \mathrm {La_{2}O_{2}CO_{3}\ \longrightarrow \ La_{2}O_{3}\ +\ CO_{2}} }$

proof

1. ↑ ^{a b} Zhaohui Han, Qing Yang, GQ Lu: Crystalline lanthanum hydroxycarbonates with controlled phases and varied morphologies prepared on non-crystalline substrates. In: Journal of Solid State Chemistry . 177, 2004, pp. 3709-3714, doi : 10.1016 / j.jssc.2004.06.044 .
2. ↑ ^{a b c d e f} Bahcine Bakiz, Frédéric Guinneton, Madjid Arab: Elaboration, characterization of LaOHCO ₃ , La ₂ O ₂ CO ₃ and La ₂ O ₃ phases and their gas solid interactions with CH ₄ and CO gases ( Memento des Originals from April 2, 2015 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 1.7 MB), MJ CONDENSED MATTER VOLUME 12, NUMBER 1 JULY 2010 
3. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
4. ↑ Wang, G., Wang, H., Nai, J., Ren, Z., Bai, J .; PVP-assisted assembly of lanthanum carbonate hydroxide with hierarchical architectures and their luminescence properties , Chemical Engineering Journal, 214 (2013), 386-393.