# Feedback Wanted - Template / Coordination Tool

**URL:** <https://discuss.avogadro.cc/t/feedback-wanted-template-coordination-tool/3814>\
**Category:** Development\
**Created:** [May 22, 2022, 9:05pm UTC](https://discuss.avogadro.cc/t/feedback-wanted-template-coordination-tool/3814 "2022-05-22T21:05:13Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ghutchis](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/ghutchis/32/456_2.png) [@ghutchis](https://discuss.avogadro.cc/u/ghutchis)\
**Post date:** [May 22, 2022, 9:05pm UTC](https://discuss.avogadro.cc/t/feedback-wanted-template-coordination-tool/3814/1 "2022-05-22T21:05:13Z")

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Many people have asked about a “click to add fragment” tool. I asked for some feedback about [fragment images](https://discuss.avogadro.cc/t/fragment-images/3639) before.

Here’s where I’d like some feedback on the UI / experience.

You want to create a metal complex .. maybe a hexa-aqua copper complex or a ferrocene.

So you switch to the template tool and you can pick the element and the coordination geometry:

 ![Screen Shot 2022-05-22 at 4.52.27 PM](https://discuss.avogadro.cc/uploads/default/original/2X/d/de7784449ebd1173c7b5d2a744e7f0ae430b2ee4.png)

Then you’d pick ligands (and the preview would update) and then click on the hydrogen atoms to replace the H with water or other ligands.

Sounds great.

How should the code “know” that you’ve switched from “insert metal with geometry” to “click on H atom to insert ligand?”

## Choice 1: “Metal Center” in ligand menu

For example, the “Ligand” menu should include a default top item of “Metal Center Only” or some text like that. In that case, you could:

- click on empty space to insert your octahedral iron (or whatever you selected)
- click on a H atom to attach an octahedral iron in place of the H atom (e.g., for building metal-metal complexes)

Then if you want to insert ligands / fragments, you’d pick something from the “Ligand” menu:

- Monodentate (water, CO, SH, PH3, pyridine, etc.)
- Bidentate (bipyridine, etc.)
- Tridentate (etc.)

In this case, the code would have to wait until you’ve clicked 2 or 3 atoms to insert bidentate or tridentate ligands.

## Choice 2: Click on 1 or more H atoms to activate the ligand menu

This possibility makes it easier to insert bidentate ligands .. those choices would become enabled once you click on some H atoms.

On the other hand, it’s much less “discoverable”..

Thoughts? Suggestions? Ideas?

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<div class="post-metadata">

**Author:** ![ghutchis](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/ghutchis/32/456_2.png) [@ghutchis](https://discuss.avogadro.cc/u/ghutchis)\
**Post date:** [May 22, 2022, 9:06pm UTC](https://discuss.avogadro.cc/t/feedback-wanted-template-coordination-tool/3814/2 "2022-05-22T21:06:19Z")

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Code for the tool, will go up in this pull request:

> <https://github.com/OpenChemistry/avogadrolibs/pull/900>
>
> Allows you to insert metal / elements with specified geometries.
> 
> Still needed…:
> \- \[\] Click to attach ligands
> \- \[\] Handling multi dentate ligands
> \- \[\] Probably more things that I forgot
> 
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