Lithium-6 (14258-72-1) Physical and Chemical Properties
Lithium-6
Isotopically enriched lithium (6Li) supplied for technical and research applications, providing a defined isotopic composition for analytical standards, materials development, and R&D workflows.
| CAS Number | 14258-72-1 |
| Family | Alkali metal isotope |
| Typical Form | Soft metallic solid or enriched solution |
| Common Grades | EP |
Lithium-6 is a stable, low-mass isotope of the alkali metal lithium (element symbol Li, atomic number 3). Structurally it is the monoisotopic atomic species with a nominal molecular/formula mass reported as 6.01512289 (computed) and a recorded relative atomic mass of 6.015122; it contains three protons, three electrons and three neutrons and carries a nuclear spin of 1. As an isotope of an s‑block metal, its electronic configuration and chemical bonding behavior are the same as the dominant isotope, with chemical reactivity governed by the fully occupied 1s core and a single valence 2s electron that is easily ionized to give the common \(+1\) oxidation state in compounds.
Chemically this isotope behaves like elemental lithium: a soft, low‑density, highly electropositive metal that forms predominantly ionic compounds. It exhibits strong reducing character, high reactivity toward protic solvents and oxidants, and a strong tendency to form hydroxides and oxides on exposure to water and air. Acid–base behaviour is typical of alkali metals: in aqueous media lithium is present as the solvated cation \(Li^+\) (strongly basic counterions notwithstanding), and metallic lithium reacts with acids to liberate hydrogen. Lithium metal and enriched lithium materials are non‑polar metallic solids in bulk, but their ionic compounds are polar and hydrophilic; lipophilicity is not a relevant descriptor for the elemental or ionic forms.
Lithium-6 has industrial and analytical relevance as an isotopic material: it is used in enriched standards, calibration solutions and specialised research applications where isotopic composition matters. Common commercial grades reported for this substance include: EP.
Basic Physical Properties (Density, Melting Point, Boiling Point)
Atomic Weight
Computed molecular weight (monoisotopic): 6.01512289. A reported relative atomic mass for the isotope is 6.015122.
Appearance and Physical State
Elemental lithium is a soft, silvery‑white metallic solid typical of the alkali metals; mechanically it can be cut with a knife and is often supplied as pieces, filings or chunks. Enriched lithium-6 material can be supplied in multiple physical forms including the metal, metal compounds (e.g., hydrides, deuterides) or as isotopic standard solutions for analytical use.
Density
No experimentally established value for this property is available in the current data context.
Melting Point
No experimentally established value for this property is available in the current data context.
Boiling Point
No experimentally established value for this property is available in the current data context.
Chemical Properties (Reactivity and Oxidation States)
Oxidation States
Lithium exhibits a dominant oxidation state of \(+1\) in compounds; the element itself is formally in oxidation state 0. Lithium-6 behaves chemically like other lithium isotopes in terms of observed oxidation states and typical ionic compound formation.
Reactivity with Air and Water
Elemental lithium is highly reactive toward oxygen and moisture. Contact with water or moist air produces lithium hydroxide and hydrogen gas; the hydrogen evolved may ignite spontaneously under certain conditions. Solid lithium rapidly forms surface oxides and hydroxides on exposure to air, and enriched metallic forms should be handled under inert atmosphere or with protective surface treatments to limit oxidative degradation. The hazard classification indicates that in contact with water the substance releases flammable gases which may ignite spontaneously (GHS hazard statement H260).
Reactivity with Acids and Bases
Lithium metal reacts with protic acids to generate hydrogen gas and soluble lithium salts. In strongly basic, anhydrous, or non‑protic media the metal is less prone to rapid hydrolysis but remains a strong reducing agent; lithium metal will also react with certain non‑aqueous electrophiles and oxidants. Corrosive behavior to skin and eyes is reported for reactive forms (GHS hazard statement H314).
Isotopic Composition
Stable Isotopes
Lithium has two stable isotopes, lithium-6 and lithium-7. Lithium-6 is present at approximately 7.5 atom percent in natural lithium and carries nuclear spin 1. The isotopic mass and computed molecular weight reported for lithium-6 are 6.015122 and 6.01512289, respectively.
Radioisotopes
No concise radioisotope decay data for lithium-6 is available in the current data context. (Lithium-6 itself is stable; other radioactive isotopes of lithium exist but are not detailed here.)
Thermodynamic Parameters
Heat Capacity and Related Data
No experimentally established value for this property is available in the current data context.
Enthalpy and Gibbs Energy
No experimentally established value for this property is available in the current data context.
Identifiers and Synonyms
Registry Numbers and Codes
CAS number: 14258-72-1
European Community (EC) numbers reported in supplier annotations include: 633-781-7; 625-439-0
ChEBI: CHEBI:52621
Wikidata: Q10322200
InChI: InChI=1S/Li/i1-1
InChIKey: WHXSMMKQMYFTQS-BJUDXGSMSA-N
SMILES: [6Li]
Molecular formula: Li
Synonyms and Common Names
Reported synonyms and name strings include: Lithium-6; 6Li isotope; Li-6 isotope; Lithium, isotope of mass 6; Lithium-6 atom; Lithium-6 deuteride; Isotope:6Li; Lithium-6 isotope; (6)Li; Lithium Isotopic Standard: Li @ 100 microg/mL in 2% HNO3 (Enriched in Li-6). (Synonym strings are supplied verbatim from depositor/supplier annotations.)
Industrial and Commercial Applications
Major Use Sectors
Lithium-6 is principally relevant to sectors that require isotopic enrichment or isotopic standards: analytical laboratories (isotope ratio and calibration standards), research institutions, and specialised industrial or technological applications where isotopic composition alters nuclear or spectroscopic properties. Regulatory annotations indicate active commercial activity status for the isotope.
Typical Application Examples
Typical applications include isotopic standards and calibration solutions for mass spectrometry and trace elemental analysis, enriched material for research into isotopic effects, and supply of enriched lithium compounds or metal for specialised manufacturing or scientific purposes. Enriched lithium solutions are distributed as defined-concentration standards (for example, microgram‑per‑milliliter solutions in acidic matrix) for analytical calibration.
Safety and Handling Overview
Storage and Handling Considerations
Enriched lithium metal and reactive lithium compounds must be stored under inert atmosphere (e.g., argon) or under suitable hydrocarbon oils to avoid contact with moisture and air. Keep away from water and aqueous environments; material is classified as water‑reactive (Water‑react. 1) and will liberate flammable hydrogen upon contact with water. Storage should isolate the material from oxidizers, acids and incompatible materials and limit the potential for mechanical damage that would expose fresh reactive surfaces.
Occupational Exposure and Protective Measures
Handle lithium-6 with appropriate process controls and personal protective equipment: chemical‑resistant gloves, eye and face protection, and protective clothing to prevent skin contact; work in well‑ventilated areas or containments to control dust and any hydrogen release. Because reactive contact with water can produce flammable gas and cause severe skin and eye damage (GHS hazard statement H314), emergency procedures should include fire control for hydrogen ignition and appropriate first‑aid measures for caustic burns. For detailed hazard, transport and regulatory information, users should refer to the product‑specific Safety Data Sheet (SDS) and local legislation.
