Lithium (Li) and water
Lithium and water: reaction mechanisms, environmental impact and health effects
|Seawater contains approximately 0.17 ppm lithium. Rivers generally contain only 3 ppb, whereas mineral water contains 0.05-1 mg lithium per liter. Large amounts of lithium were found in holy water from Karlsbad, Marienbad and Vichy. In solution it is only found as Li+ (aq). |
Lithium reacts intensely with water, forming lithium hydroxide and highly flammable hydrogen. The colourless solution is highly alkalic. The exothermal reactions lasts longer than the reaction of sodium and water, which is directly below lithium in the periodic chart.
2 Li(s) + 2 H2O -> 2 LiOH (aq) + H2(g)
At 750oC lithium reacts with hydrogen to lithium hydride (LiH). The white powder that forms releases hydrogen gas upon later reaction with water, in amounts of 2800 liter per kilogram hydride. As such, lithium can be applied as hydrogen storage.
Elementary lithium is not very water soluble, but it does react with water.
Lithium is present in many minerals, mostly in amblygonite, petalite, lepidolite and spodumene. Spodumene (LiAlSi2O6) is most suitable for commercial purposes.
Falls under water hazard class 1, weakly harmful in water. Lithium is not a very big threat to flora and fauna, nor on the mainland, nor in aquatic environments. It is readily absorbed by plants, causing plants to be an indicator of soil lithium concentrations. Lithium is not a dietary mineral for plants, but it does stimulate plant growth. Too much lithium may be toxic. To prevent toxicity, calcium may be added to soils to prevent uptake of lighter minerals. The amount of lithium in plants usually lies between 0.2 and 30 ppm.
The amount of lithium in the human body is approximately 7 mg. Lithium has no known biological use, and it is not readily absorbed by the body. Most lithium is excreted directly upon uptake. Although lithium is not an essential element, it may influence metabolism. Upon oral intake lithium is mildly toxic. Physical tolerance differs between individuals. In the 1940s some patients that applied lithium chloride as a salts replacement died.