The molar mass of titanium dioxide, TiO2, is 79.865 g/mol. That single number is what connects a mass you can weigh to an amount of substance you can react: one mole is 79.865 g, and a gram of it is 7.54e+21 formula units. The calculator turns any weighed mass into that count, and reports the amount in moles, millimoles and the mass of a single formula unit alongside it.
The figure comes from the formula. Titanium dioxide is 47.867 (Ti) + 2 × 15.999 (O), which is 79.865 g/mol, taking standard atomic weights, and every page here computes that sum rather than quoting it. Titanium makes up the largest share of the mass: 1 of the 3 atoms in a formula unit is titanium, and they account for 47.867 g of the 79.865 g, or 59.93% by mass. The derivation table below breaks the whole molecule down element by element.
The numbers a bench actually uses sit at the millimole scale. One millimole of titanium dioxide is 79.865 mg and one micromole is 79.865 µg, so a balance reading to a milligram places you within 12.52 µmol. A single formula unit weighs 1.3262e-22 g, which is why the count in the gauge runs into the sextillions for any mass you can see.
The white pigment in paint, sunscreen and toothpaste, and the most opaque white known. Also a photocatalyst under ultraviolet light. At 79.865 g/mol it is heavier than 3 of the 8 oxides covered here, and that ranking matters more than it looks: copper(II) oxide has a molar mass of 79.545 g/mol, so a gram of it contains 0.402% more formula units than a gram of titanium dioxide. Weigh by mass and you are not weighing equal amounts of substance.
Purity is the usual gap between the calculation and the balance. A reagent sold at 98% means 1.5973 g of a nominal 79.865 g is something else, so for exact work you divide the weighed mass by the assay figure on the certificate. For most purposes the difference is smaller than the error in reading the meniscus, but it is systematic rather than random, so it does not average out.
The formula
m- The mass of titanium dioxide in grams
79.865- The molar mass of titanium dioxide in g/mol, derived from its formula
N- The number of formula units that mass contains
How it works, step by step
- Enter a mass of titanium dioxide in grams.
- It is divided by the molar mass, 79.865 g/mol, giving the amount in moles.
- That amount is multiplied by the Avogadro constant, 6.02214076 × 10²³ per mole, to give the number of formula units.
- The panel also reports the amount in moles and millimoles and the mass of one formula unit.
Worked examples
0.5 g of titanium dioxide as a molecule count
0.5 g divided by 79.865 g/mol is 0.00626056 mol, and multiplying by the Avogadro constant gives 3.77e+21 formula units of titanium dioxide. The same mass is 6.2606 mmol, which is the figure a reaction is actually planned in.
5 g of titanium dioxide as a molecule count
5 g divided by 79.865 g/mol is 0.0626056 mol, and multiplying by the Avogadro constant gives 3.77e+22 formula units of titanium dioxide. The same mass is 62.606 mmol, which is the figure a reaction is actually planned in.
50 g of titanium dioxide as a molecule count
50 g divided by 79.865 g/mol is 0.626056 mol, and multiplying by the Avogadro constant gives 3.77e+23 formula units of titanium dioxide. The same mass is 626.06 mmol, which is the figure a reaction is actually planned in.
How to read your score
Frequently asked questions
What is the molar mass of titanium dioxide (TiO2)?
It is 79.865 g/mol. That is the sum of the standard atomic weights of every atom in the formula: 47.867 (Ti) + 2 × 15.999 (O). One mole of titanium dioxide therefore weighs 79.865 g, and a gram of it is 12.521 mmol.
What percentage of titanium dioxide is titanium?
59.93% by mass. Each formula unit contains 1 titanium atom contributing 47.867 g of the 79.865 g total, so 100 g of titanium dioxide contains 59.93 g of titanium and a kilogram contains 599.35 g of it.
How many molecules are in one gram of titanium dioxide?
About 7.54e+21. One gram is 0.0125211 mol, and each mole contains 6.02214076 × 10²³ formula units by definition of the mole, so the count is that constant divided by 79.865.
How much does a single molecule of titanium dioxide weigh?
1.3262e-22 g, which is 79.865 daltons. It is the molar mass divided by the Avogadro constant, and the number in daltons is numerically the same as the molar mass in g/mol — that equivalence is what makes the mole convenient.
Is molar mass the same as molecular weight?
They are the same number in ordinary use but not the same quantity. Molecular weight, properly relative molecular mass, is a ratio and has no unit: for titanium dioxide it is 79.865. Molar mass carries grams per mole: 79.865 g/mol. Because the mole is defined so those agree, you can read one off the other.
Why is the molar mass not a whole number?
Because standard atomic weights are averages over the isotopes found in nature. Titanium is quoted as 47.867 rather than a whole number for that reason, and the same applies to the other elements here, which is why titanium dioxide comes out at 79.865 g/mol rather than 80.
Molar mass, composition and mole equivalents of titanium dioxide
| Element | Atoms | Atomic weight | Contribution (g/mol) | By mass |
|---|---|---|---|---|
| Titanium (Ti) | 1 | 47.867 | 47.867 | 59.93% |
| Oxygen (O) | 2 | 15.999 | 31.998 | 40.07% |
| Total — one mole of titanium dioxide | 79.865 | 100% |
Standard atomic weights, IUPAC 2021. The contribution column is atoms × atomic weight, and the total is the molar mass this page uses: 79.865 g/mol.
| Amount | Mass (g) | Mass (mg) | Formula units |
|---|---|---|---|
| 1 µmol | 0.000080 | 0.079865 | 6.022e+17 |
| 10 µmol | 0.00079865 | 0.79865 | 6.022e+18 |
| 100 µmol | 0.0079865 | 7.9865 | 6.022e+19 |
| 1 mmol | 0.079865 | 79.865 | 6.022e+20 |
| 10 mmol | 0.79865 | 798.65 | 6.022e+21 |
| 50 mmol | 3.99325 | 3993.25 | 3.011e+22 |
| 100 mmol | 7.9865 | 7986.5 | 6.022e+22 |
| 250 mmol | 19.9662 | 19,966.2 | 1.506e+23 |
| 500 mmol | 39.9325 | 39,932.5 | 3.011e+23 |
| 750 mmol | 59.8987 | 59,898.7 | 4.517e+23 |
| 1 mol | 79.865 | 79,865 | 6.022e+23 |
| 2 mol | 159.73 | 159,730 | 1.204e+24 |
| 5 mol | 399.325 | 399,325 | 3.011e+24 |
| 10 mol | 798.65 | 798,650 | 6.022e+24 |
Mass is the amount multiplied by 79.865 g/mol. The last column is that amount multiplied by the Avogadro constant, 6.02214076 × 10²³ per mole.
| Compound | Formula | Molar mass (g/mol) | Millimoles in 1 g |
|---|---|---|---|
| Calcium oxide | CaO | 56.077 | 17.833 |
| Silicon dioxide | SiO2 | 60.083 | 16.644 |
| Copper(II) oxide | CuO | 79.545 | 12.572 |
| Titanium dioxide (this page) | TiO2 | 79.865 | 12.521 |
| Zinc oxide | ZnO | 81.379 | 12.288 |
| Manganese dioxide | MnO2 | 86.93604 | 11.503 |
| Aluminium oxide | Al2O3 | 101.9601 | 9.8078 |
Ordered by molar mass. The last column is 1000/M, which is the number a weighed gram actually gives you.