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Lithium Carbonate

Li2CO3 salt

Properties

StateSolid
ColorWhite crystalline powder
SolubilitySparingly soluble in water (13 g/L at 20 °C); insoluble in ethanol
Melting Point723 °C
Boiling Point1310 °C (decomposes)

About Lithium Carbonate

Lithium carbonate is the gateway compound for nearly every downstream lithium chemistry on earth. Spodumene concentrates from Australian hard-rock mines and brine pumped from the Atacama salars both end up as Li2SO4 solutions, and adding hot Na2CO3 precipitates Li2CO3 because lithium carbonate has the unusual property — for an alkali metal carbonate — of being only sparingly soluble in water (13 g/L at 20 °C, dropping further with temperature; the rare retrograde solubility curve). That precipitation step is where 'battery-grade' (>=99.5%) and 'technical-grade' (>=99%) specifications get drawn, and it's the reason global Li2CO3 production scaled from roughly 150,000 tonnes in 2015 to past 1 million tonnes in 2024 — Tesla's Gigafactory and every other lithium-ion plant downstream calcines Li2CO3 with NiO/MnO2/CoO at 700-900 °C to make NMC, NCA, and LFP cathode oxides. The same compound has a separate, much older life as the first-line mood stabilizer for bipolar disorder, FDA-approved in 1970. Therapeutic serum levels run 0.6-1.2 mmol Li/L, and toxicity sets in above 1.5 mmol/L — one of the narrowest therapeutic windows in clinical pharmacology, which is why every patient on lithium gets a quarterly serum draw. The same Li-ion modulates GSK-3 and inositol monophosphatase signaling that is now of intense interest in Alzheimer's research.

Where you'll encounter it

If you've ever opened a laptop, started an EV, or watched a psychiatry rotation prescribe a 300 mg lithium tablet TID for bipolar I, you've seen Li2CO3 at both ends of its career — the cathode-precursor end and the mood-stabilizer end. In a cathode plant the Li2CO3 spec sheet matters down to single-digit ppm Na, K, Ca, Mg, B, Fe — anything higher and you get capacity loss and dendrite-driven failure in finished cells. On a psychiatry inpatient unit the same compound shows up as 300 mg orange tablets dispensed three times daily with quarterly serum draws targeting 0.6-1.2 mmol/L, and every new ACE inhibitor or NSAID added to the chart triggers a stat lithium level because dehydration can push a stable patient past 1.5 mmol/L within 48 hours.

Common Uses

  • Cathode-precursor calcination feedstock for LiCoO2, LiFePO4, LiNiMnCoO2, and LiNi0.8Co0.15Al0.05O2
  • First-line mood stabilizer for bipolar I disorder (Eskalith, Lithobid; FDA 1970)
  • Adjunct therapy for treatment-resistant depression at lower serum-level targets
  • Glaze flux in pottery and porcelain — lowers melting temperature and improves thermal-shock resistance
  • Cement-set accelerator for low-temperature concrete pours
  • Aluminum-smelting bath additive (Hall-Heroult cell electrolyte chemistry)
  • Starting material for LiOH and LiCl synthesis in lithium-chemistry refineries
  • Lithium-isotope source for 6Li enrichment in tritium-breeding research

Safety Information

GHS: Acute Tox. 4 oral (H302), Skin Irrit. 2 (H315), Eye Irrit. 2A (H319), Repr. 1A (H360FD — known human reproductive toxicant; teratogenic in first trimester causing Ebstein's anomaly cardiac defect). Therapeutic serum level 0.6-1.2 mmol Li/L; toxic above 1.5 mmol/L causes tremor, ataxia, confusion, seizures, and acute renal failure; serum level over 3.5 mmol/L is a hemodialysis indication. Pregnancy category D — pregnancy testing before prescribing is standard. OSHA does not have a specific PEL for lithium compounds; manufacturers recommend handling as a Category 4 acute oral toxicant with dust controls.

This safety summary is for educational reference only and may not be complete. It is not a substitute for Safety Data Sheets (SDS), medical advice, or professional chemical safety guidance. Always consult appropriate SDS and qualified professionals before handling chemicals.

Constituent Elements

Frequently Asked Questions

What is the molar mass of lithium carbonate?
Li2CO3 is 73.89 g/mol — 2 Li (2 x 6.94 = 13.88) + C (12.011) + 3 O (3 x 15.999 = 47.997). One key calculation: 73.89 g of Li2CO3 contains 13.88 g of elemental lithium, so the lithium mass fraction is 18.8% — the number cathode plants use when sizing Li2CO3 input for a target NMC811 production rate.
Why is lithium carbonate used for bipolar disorder?
Li-ion inhibits glycogen synthase kinase 3 beta (GSK-3-beta) and inositol monophosphatase, dampening the second-messenger amplification that appears overactive in mania. Onset takes 1-2 weeks for full mood-stabilizing effect at 600-1200 mg/day divided doses, targeting 0.6-1.2 mmol Li/L in serum drawn 12 hours post-dose. The narrow window — toxicity above 1.5 mmol/L — and the kidney-cleared pharmacokinetics mean every dehydration episode, every NSAID start, every ACE inhibitor add-on can push a stable patient into toxicity, which is why lithium carries the heaviest monitoring burden of any psychiatric medication.
How is battery-grade lithium carbonate produced?
Brine or spodumene-leach Li2SO4 solutions are pH-adjusted, treated with hot 200 g/L Na2CO3, and Li2CO3 precipitates because of its retrograde solubility — solubility decreases with temperature, so the hotter the addition, the cleaner the precipitation. Battery grade (>99.5%) requires multiple recrystallizations and impurity removal of Na, K, Ca, Mg, B, and Fe down to single-digit ppm. The carbonate is then dried, milled, and shipped to cathode plants where it reacts with transition-metal oxides at 700-900 °C in oxygen to form layered LiMO2 cathodes.