16940-66-2

Appearance: White to off-white crystalline powder.
Density: 1.035 g/cm³ at 25°C.
Melting Point: >300°C (decomposes).
Boiling Point: Decomposes at 500°C.
Solubility:
- Soluble in water (stable at pH 14, decomposes in acidic conditions).
- Soluble in methanol (13 g/100 mL) and ethanol (3.16 g/100 mL), but decomposes to borate salts.
- Slightly soluble in tetrahydrofuran and polyethylene glycol.
- Insoluble in ether, benzene, and hydrocarbons.
Hygroscopicity: Strongly hygroscopic, easily absorbs moisture and decomposes in humid air.

Stability: Stable in dry air and in alkaline solutions (pH 14); decomposes in acidic conditions to release hydrogen gas.
Reduction Reactions:
- Reduces aldehydes to primary alcohols and ketones to secondary alcohols.
- Can selectively reduce carbonyl groups in the presence of other functional groups (e.g., esters, amides).
- Reacts with water to release hydrogen gas:NaBH₄ + 2H₂O → NaBO₂ + 4H₂↑ \][^156^].
Applications as a Reducing Agent: Widely used in organic synthesis for reducing carbonyl compounds, esters, and amides under mild conditions.

Typically prepared by reacting sodium hydride with boron trifluoride or by reducing boric acid with sodium metal and hydrogen.

Organic Synthesis: Used as a selective reducing agent for carbonyl compounds.
Pharmaceuticals: Used in the synthesis of antibiotics, antiviral drugs, and cancer medications.
Pulp and Paper Industry: Used as a bleaching agent and in the treatment of mercury-containing wastewater.
Hydrogen Generation: Potential use in hydrogen storage and fuel cells due to its ability to release hydrogen gas upon hydrolysis.

Health Risks: Inhalation or skin contact can cause irritation and harm. Decomposition products (e.g., hydrogen gas) are flammable.
Storage: Store in a dry, cool place; keep away from moisture and acidic environments. Handle in a well-ventilated area.