---
title: "Adenine Structure (C5H5N5): 3D Model, Formula & Molar Mass | MolDraw"
url: https://www.moldraw.com/molecules/adenine.html
description: "Structure of Adenine (C5H5N5, 135.13 g/mol): rotatable 3D model, 2D skeletal formula, IUPAC name, SMILES, shape, polarity, uses and FAQ."
lang: en
publisher: Scidart Academy
generated: 2026-10-26
---
[MolDraw](https://www.moldraw.com/) › [3D molecule models](https://www.moldraw.com/molecules/) › Adenine structure

# Adenine structure and 3D model (C5H5N5)

Adenine is a purine base: a six-membered pyrimidine ring fused to a five-membered imidazole ring, with an NH₂ group at C6. It pairs with thymine in DNA and uracil in RNA.

**Quick answer:** Adenine is **C5H5N5**, molar mass **135.13 g/mol**. Completely flat, nitrogen-rich ring system; polar but only slightly soluble in cold water.

Atom labels Hydrogens Spin

Drag to rotate · pinch or scroll to zoom. 3D coordinates: computed with RDKit (ETKDG conformer, force-field optimised).

## Adenine at a glance

| Formula | C5H5N5 |
| --- | --- |
| Molar mass | 135.13 g/mol |
| IUPAC name | 7H-purin-6-amine |
| Atoms / bonds | 15 / 16 |
| H-bond donors / acceptors | 2 / 4 |
| logP (estimated) | -0.1 |
| SMILES | `C1=NC2=NC=NC(=C2N1)N` |
| InChIKey | `GFFGJBXGBJISGV-UHFFFAOYSA-N` |
| PubChem | [190](https://pubchem.ncbi.nlm.nih.gov/compound/190) |

![2D structural formula of Adenine (C5H5N5)](https://www.moldraw.com/molecules/img/adenine.svg)

2D structure (skeletal formula) · [Draw it in MolDraw](https://www.moldraw.com/)

## What the 3D model of Adenine shows

The model contains **15 atoms** (10 heavy atoms and 5 hydrogens) joined by **16 bonds**; in ball-and-stick mode every stick is one bond, and double or aromatic bonds are drawn as multiple sticks. Switch to *space-filling* to see the molecule as its electron cloud, scaled to van der Waals radii: this is the shape other molecules actually "feel". It can donate 2 and accept 4 hydrogen bonds, and its estimated logP of -0.1 means it is very water-loving (hydrophilic). Its topological polar surface area is 80 Ų.

## Shape and bond angles

| Atom(s) | Geometry / hybridisation | Angles & lengths |
| --- | --- | --- |
| ring atoms | Trigonal planar, sp²; fused aromatic rings | ≈ 108–128° |
| exocyclic NH₂ | Near-planar, conjugated with the ring | ≈ 120° |

### Is Adenine polar?

Yes. Its ring nitrogens accept hydrogen bonds and the NH₂ and ring N–H donate them. Strong stacking in the solid keeps its water solubility low.

## Elemental composition of C5H5N5

| Element | Atoms | Mass (g/mol) | Mass % |
| --- | --- | --- | --- |
| Carbon (C) | 5 | 60.055 | 44.44% |
| Hydrogen (H) | 5 | 5.040 | 3.73% |
| Nitrogen (N) | 5 | 70.035 | 51.83% |

Calculated from IUPAC standard atomic weights. Check any formula with the [molar mass calculator](https://www.moldraw.com/tools/free-chem-tools/molar-mass-calculator.html).

## Uses of adenine

- One of the four bases in DNA and RNA
- Part of ATP, NAD and coenzyme A
- Used in cell culture media and research

## Interesting facts

- Adenine pairs with thymine through two hydrogen bonds.
- It has been formed in experiments from hydrogen cyanide, and has been found in meteorites.
- Adenine was once called vitamin B4, but it is no longer considered a vitamin.

**Drawing structures for your notes?** MolDraw is a free online chemical structure editor for molecules, reactions and lab diagrams.

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## Frequently asked questions

### What is the structure of Adenine?

Adenine is a purine base: a six-membered pyrimidine ring fused to a five-membered imidazole ring, with an NH₂ group at C6. It pairs with thymine in DNA and uracil in RNA. Its SMILES is C1=NC2=NC=NC(=C2N1)N.

### Is adenine a purine or a pyrimidine?

A purine. Purines (adenine, guanine) have two fused rings; pyrimidines (cytosine, thymine, uracil) have one.

### How many hydrogen bonds does adenine form with thymine?

Two: one from its NH₂ group and one to its ring nitrogen N1.

### What is the chemical formula and molar mass of Adenine?

Adenine is C5H5N5 with a molar mass of 135.13 g/mol. It contains 15 atoms: 5 carbon, 5 hydrogen, 5 nitrogen.

### What is the IUPAC name of Adenine?

The IUPAC name is 7H-purin-6-amine.

### How do I draw Adenine?

Open the MolDraw editor, paste the SMILES C1=NC2=NC=NC(=C2N1)N or type "Adenine" in name search, and the structure is drawn for you. You can then export it as PNG, SVG, MOL or CDXML.

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