Infographic on litmus paper. The graphic explains how litmus dyes can be derived from orcinol, itself sourced from species of lichens. The chromophore of the litmus dye is 7-hydroxyphenoxazone. In acidic solutions, the protonated structure is red, while in alkaline solutions the deprotonated structure is blue.

What links litmus paper and lichens?

Infographic on litmus paper. The graphic explains how litmus dyes can be derived from orcinol, itself sourced from species of lichens. The chromophore of the litmus dye is 7-hydroxyphenoxazone. In acidic solutions, the protonated structure is red, while in alkaline solutions the deprotonated structure is blue.
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Along with universal indicator, litmus paper is one of the most commonly encountered pH indicators in school chemistry lessons. Unlike the range of colours produced by the former, litmus is pink-red in acidic solutions and blue in alkaline solutions. This graphic highlights its complex origins in lichens and the chemical changes that account for its colour change.

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The year in chemistry: 2022’s biggest chemistry stories

Infographic summarising twelve significant chemistry stories from 2022. More detail on each is provided in the text of the post below.
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For the first time since the onset of the pandemic, COVID’s domination of the science news cycle waned in 2022. The focus increasingly shifted to the longer-term crisis we face: that of climate change and taking steps to make components of our modern lives more sustainable. This graphic summarises some of the key chemistry news over the past year, with more detail and links to related articles below.

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