 |
| Name |
lanthanum |
| Symbol |
La |
| Atomic Weight |
138.9055 |
| Atomic Number |
57 |
| CAS ID |
7439-91-0 |
| Group Number |
|
| Group Name |
Lanthanoid |
| Period Number |
6 |
| Origin of Name |
From the Greek, lanthanein = "to lie
hidden." |
| Year Discovered |
1839 |
| Discovery Credits |
Discovered by C. G. Mosander at Stockholm,
Sweden. |
| Class |
Metallic |
| Color |
Silvery White |
| Standard State |
Solid at 77 F & 298 K |
| Description |
Soft, silvery-white metal; rapidly tarnishes
in air and burns easily. Reacts with water to give hydrogen gas. Used in
optical glass and for flints. La2+ is used as a biological
tracer for calcium Ca2+. Diagnostic tests:
There are no simple diagnostic tests to identify lanthanum.
X-ray fluorescence spectroscopy is commonly employed to identify and
analyze members of the Rare-Earth group elements.
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