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Ants, Cells & Atoms

Life and matter below the width of a hair.

Section

Molecule Shapes

Everyday molecules and crystals, drawn from published coordinates, and how their shape sets what a substance does. Medicines appear only as chemical history.

5 entries

  1. 10−1 m: no entry
  2. 10−2 m: no entry
  3. 10−3 m: has entries
  4. 10−4 m: has entries
  5. 10−5 m: no entry
  6. 10−6 m: no entry
  7. 10−7 m: no entry
  8. 10−8 m: no entry
  9. 10−9 m: has entries
  10. 10−10 m: has entries
Illustration: two ice cubes floating in a glass of water, a strand of hair on the table beside it, not to scale; each cube sits mostly under water. Illustration

Mechanism explainer[10−10 m]

Water Molecule: The Bent Shape Behind Floating Ice

A water molecule is bent, its two O–H bonds about 104.5° apart. That makes it polar, the polar molecules bond into an open hexagonal lattice, and ice floats.

Image: Illustration: Ants, Cells & Atoms, all rights reserved

Illustration: Ants, Cells & Atoms. Generated schematic illustration — not a photograph, micrograph or specimen record. © Ants, Cells & Atoms, all rights reserved.

Meadowsweet in flower: cream-white flower heads and round buds on reddish stems, toothed leaves below; photograph, natural color; no scale.

Field-guide entry[10−10–10−9 m]

Acetylsalicylic Acid: A Form Made in 1853, 'Aspirin' in 1899

A form of acetylsalicylic acid was made in 1853 and a pure one by 1859; Bayer named it Aspirin in 1899. Who at Bayer made it pure was still disputed in 2015.

Image: “Filipendula ulmaria detail” by Marterum (2020) · CC0 1.0

"Filipendula ulmaria detail" by Marterum — https://commons.wikimedia.org/wiki/File:Filipendula_ulmaria_detail.jpg — CC0 1.0 (https://creativecommons.org/publicdomain/zero/1.0/)

Twelve snow crystals photographed by Wilson Bentley, printed white on black in 1902, no scale; six-armed plates and stars, each numbered.

Field-guide entry[10−4–10−3 m]

Snowflakes: The Six-Fold Pattern Starts in the Molecule

Snow crystals get their six-fold symmetry from the hexagonal rings water molecules form in ice; temperature and humidity then pick plate, needle or star.

Image: “SnowflakesWilsonBentley” by Wilson Bentley (1902) · Public domain

"SnowflakesWilsonBentley" by Wilson Bentley (1902) — https://commons.wikimedia.org/wiki/File:SnowflakesWilsonBentley.jpg — Public domain (photographs by Wilson Bentley, who died in 1931, published as Plate XIX of his snow-crystal studies in the annual summary of the Monthly Weather Review for 1902: public domain in the US (published before 1930) and in the EU (life of the author plus 70 years, ended 2001); the scan is from the NOAA Historic NWS Collection (image wea02087))

Halite crystals on a matrix of smaller crystals, no scale given; photograph, natural color; clear blocks whose flat faces meet at right angles.

Mechanism explainer[10−10 m]

The Stick Fiction: Ball-and-Stick Models Invent the Gaps

Ball-and-stick models draw bonds as rods with gaps between atoms. In water, bonded nuclei sit 0.958 Å apart, 35% of the way to where their spheres would touch.

Image: “Clear Halite Crystals on matrix” by IvanSakhno (2018) · CC BY 4.0

"Clear Halite Crystals on matrix" by IvanSakhno — https://commons.wikimedia.org/wiki/File:Clear_Halite_Crystals_on_matrix.jpg — CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)