Chemistry
Free PNG images in the category “Chemistry”: 14 files with transparent background, no sign-up.
Skeletal formulas almost throughout: a five-membered ring with its NH marked, toluene in circle notation, fused heterocycles with a bridgehead nitrogen, long drug structures with amide and ether chains, labelled reaction schemes with bracketed intermediates, and one ball and stick model with a red oxygen.
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Molecule Chemistry Anthracene Chemical PNG
Chemistry Chemical compound Curcumin PNG
Organic acid anhydride Simple aromatic ring PNG
Mercaptopurine Simple aromatic ring PNG
Aromaticity Simple aromatic ring Pyridine PNG
Isoquinoline Naphthalene Aromaticity Simple PNG
Aryne Chlorobenzene Aniline Chemistry PNG
Aniline Skeletal formula Molecule PNG
Hepatitis C virus Grazoprevir Chemical PNG
Quinoline Ether Chemical compound Chemistry PNG
Acridine Chemical structure Simple aromatic PNG
Estrogen receptor Aromaticity Chemical PNG
Stacking Organic chemistry Benzene Pi bond PNG
Lactam Aromaticity Indole Heterocyclic PNG
Chemistry versus Molecule
Science & Education has both Chemistry and Molecule, and they overlap. Molecule leans toward 3D models — spheres, sticks, space-filling shapes. Chemistry is the paper side of the subject: skeletal formulas and reaction schemes the way they appear in a textbook or a journal. Laboratory and Experiment cover the glassware.
Checking a structure before you use it
Source files are sometimes redrawn by hand and pick up errors: a missing hydrogen, a stray charge, a bond in the wrong place. If students or reviewers will read the formula, compare it with a reference database before it goes into a slide or an exam paper.
Line art on transparency
The formulas are black strokes on a transparent background. On a dark slide they vanish, so invert them or place them on a white card. Atom labels are the first thing to blur when the image is scaled down; choose the widest file available for print.