Scientists in Australia and New Zealand produced small metallic snowflakes while operating at the atomic scale. Why is that important? Because nanomaterials are causing a revolution in engineering and technology by getting individual atoms to work together. It's cool to make snowflakes. 

Nanoscale structures can help with electronic manufacturing, make materials stronger yet lighter, or aid in environmental clean-ups by binding to toxins. A nanometer is one billionth of a metre, or about 50,000 times smaller than the diameter of a human hair.

 Scientists from New Zealand and Australia have been experimenting with gallium, a soft, silvery metal used in semiconductors that has the peculiar ability of liquifying at just above room temperature, to make metallic nanocrystals. Science published a report on their findings on December 8th. 

In Australia, under the direction of Professor Kourosh Kalantar-Zadeh at the University of New South Wales, colleagues included Professor Nicola Gaston, research fellow Dr. Steph Lambie, and Drs. Krista Steenbergen of Te Herenga Waka and Victoria University of Wellington. Platinum, bismuth, silver, aluminium, copper, zinc, tin, and nickel were among the materials used in the lab by the Australian team. 

Gallium dissolved metals when heated to a high temperature. The metallic crystals appeared after cooling, but the gallium remained liquid. The MacDiarmid Institute for Advanced Materials and Nanotechnology is a national Center of Research Excellence. The New Zealand team used simulations of molecular dynamics to determine why different-shaped crystals form from various metals.

 (The study was funded by the government's Marsden Fund.) According to what we are learning, the structure of the liquid gallium is crucial, adds Gaston. That's unusual because we typically imagine liquids as being randomly or loosely formed. The researchers demonstrated that different-shaped crystals emerge as a result of interactions between the atomistic structures of the various metals and the liquid gallium.

Cubes, rods, hexagonal plates, and zinc snowflake shapes were among the crystal forms. The snowflake pattern is explained by zinc's six-branched symmetry, in which each atom is surrounded by six neighbours at comparable distances. According to Gaston, 'this bottom-up strategy relies on atoms self-assembling in contrast to top-down approaches to create nanostructure — by cutting away material. 

This is how nanoparticles are created in nature, and it is both less wasteful and far more accurate than top-down approaches. According to her, the study has revealed a previously untapped route for metallic nanostructures. Another pretty cool thing to do is to make metallic snowflakes.