Molar Mass of B2O3 (Diboron Trioxide)

Molar Mass Calculator

What is the molar mass of B₂O₃?

Answer

M(B₂O₃) ≈

69.62 g/mol

Atomic weights: IUPAC standard values (CIAAW, 2024); the sum is rounded to the decimal places of the least precise one — B: 10.81.

Contribution of each element
Element	Atoms, n	Atomic weight, A	n × A, g/mol Mass fraction, w	Mass fraction, w
Bboron	2	10.81	21.62 w ≈ 31.06%	≈ 31.06%
Ooxygen	3	15.999	47.997 w ≈ 68.94%	≈ 68.94%
Σ = 69.617 ≈ 69.62 g/mol w = 100%				100%

Atomic weights: CIAAW, Abridged Standard Atomic Weights (2024)

Mass fractions of the elements

O 68.94%

B 31.06%

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Molar masses of substances nearby

Formula	M, g/mol
(NH₄)₂S (ammonium sulfide)	68.14
LiNO₃ (lithium nitrate)	68.94
NaNO₂ (sodium nitrite)	68.995
B₂O₃ (diboron trioxide)	69.62
Ga (gallium)	69.723
C₅H₁₀ (cyclopentane)	70.135
Cl₂ (chlorine)	70.90

FAQ

What is the molar mass of B2O3?

M(B₂O₃) ≈ 69.62 g/mol

How to calculate the molar mass of B₂O₃?

Add up the atomic weights of all the atoms in the formula: 2 × 10.81 + 3 × 15.999 = 69.617 ≈ 69.62 g/mol.

How many grams are in 2 moles of B₂O₃?

m = n × M = 2 mol × 69.62 g/mol = 139.24 g.

See Also