Going from grams to moles for titanium dioxide means dividing by its molar mass, 79.865 g/mol. One gram is 0.0125211 mol, or 12.5211 mmol; 100 mg is 1.2521 mmol; and a 79.865 g portion is exactly one mole. The division is the whole calculation, but the molar mass has to be the one for the exact formula you have, TiO2, which is where these figures come from.
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.
Balance resolution is the practical limit here. On a two-decimal balance the smallest step is 10 mg, which is 0.1252 mmol of titanium dioxide; on a three-decimal balance it is 1 mg, or 12.52 µmol. To hit a target within 1% you therefore need to weigh at least a gram on the first and at least 100 mg on the second, and below that a stock solution measured by pipette beats weighing.
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 you weighed, in grams
79.865- The molar mass of titanium dioxide in g/mol, derived from its formula
n- The amount of substance in moles
How it works, step by step
- Enter the mass you weighed, in grams.
- It is divided by 79.865 g/mol, the molar mass of titanium dioxide.
- The result is the amount of substance in moles, with millimoles and micromoles beneath it.
- Check it against the table if you want the figure for a standard weighing rather than a typed mass.
Worked examples
0.25 g of titanium dioxide in moles
0.25 ÷ 79.865 = 0.00313028 mol, or 3.1303 mmol. If the balance was reading to 1 mg, the last digit of that mass is worth 12.52 µmol, so quoting the answer to more than four significant figures claims a precision the weighing did not have.
2 g of titanium dioxide in moles
2 ÷ 79.865 = 0.0250423 mol, or 25.042 mmol. If the balance was reading to 1 mg, the last digit of that mass is worth 12.52 µmol, so quoting the answer to more than four significant figures claims a precision the weighing did not have.
25 g of titanium dioxide in moles
25 ÷ 79.865 = 0.313028 mol, or 313.03 mmol. If the balance was reading to 1 mg, the last digit of that mass is worth 12.52 µmol, so quoting the answer to more than four significant figures claims a precision the weighing did not have.
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 do I convert grams of titanium dioxide to moles?
Divide the mass in grams by 79.865 g/mol. So 1 g is 0.0125211 mol, 10 g is 0.125211 mol and 100 g is 1.25211 mol. Nothing else enters the calculation — no volume, no temperature, no concentration.
How many moles is 100 g of titanium dioxide?
1.25211 mol, which is 1252.11 mmol. Read the other way, one mole of titanium dioxide is 79.865 g, so 100 g is 1.252 of a mole.
What about milligrams and micromoles?
The same division, scaled. A milligram of titanium dioxide is 12.521 µmol, 10 mg is 125.21 µmol and 100 mg is 1.2521 mmol. Working in µmol per mg avoids the string of leading zeros that mol per g produces at this scale.
Does purity change the number of moles?
Yes, in proportion. A 98% pure sample weighing 1 g contains 0.98 g of titanium dioxide, which is 0.0122707 mol rather than 0.0125211 mol. The calculator assumes the mass you enter is the compound itself, so divide by the assay figure first if you need the corrected amount.
Grams to moles reference for 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.
| On the balance | Moles | Millimoles | Micromoles |
|---|---|---|---|
| 1 mg | 0.000013 | 0.0125211 | 12.5211 |
| 5 mg | 0.000063 | 0.0626056 | 62.6056 |
| 10 mg | 0.000125211 | 0.125211 | 125.211 |
| 25 mg | 0.000313028 | 0.313028 | 313.028 |
| 50 mg | 0.000626056 | 0.626056 | 626.056 |
| 100 mg | 0.00125211 | 1.25211 | 1252.11 |
| 250 mg | 0.00313028 | 3.13028 | 3130.28 |
| 500 mg | 0.00626056 | 6.26056 | 6260.56 |
| 1 g | 0.0125211 | 12.5211 | 12,521.1 |
| 2 g | 0.0250423 | 25.0423 | 25,042.3 |
| 5 g | 0.0626056 | 62.6056 | 62,605.6 |
| 10 g | 0.125211 | 125.211 | 125,211 |
| 25 g | 0.313028 | 313.028 | 313,028 |
| 50 g | 0.626056 | 626.056 | 626,056 |
| 100 g | 1.25211 | 1252.11 | 1252112.940587 |
| 250 g | 3.13028 | 3130.28 | 3130282.351468 |
| 500 g | 6.26056 | 6260.56 | 6260564.702936 |
Every row is the mass divided by 79.865 g/mol. A balance reading to 1 mg resolves 12.52 µmol of this compound, which is the smallest step the middle columns can really move in.
| 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.