Personally, in Pechini synthesis I generally use 1:2 proportion of metals to citric acid, but since is the complexing agent it will depend on your system and the metals in it because the complex formation constant will vary.

There are other factors that alter a particle's size and morphology, but the sol-gel route of synthesis is not an ideal route to control this parameter.

Dear all, indeed complexing agents have additional roles on the morphology, shape, size and size distribution. Various studies are devoted to witness on their benificial role. Please have a look at the following documents. My Regards

https://doi.org/10.1155/2013/791641

https://doi.org/10.1016/j.micromeso.2016.02.020

doi: 10.1021/la903470f

DOI:10.3390/batteries6040048

Dear Amer Sakran . See the following useful link: https://ir.nsfc.gov.cn/paperDownload/ZD5069959.pdf

Kindly see also the following useful RG link: Article High-Performance Lithium-Rich Layered Oxide Material: Effect...

Also check please the following useful RG link: Article High-Performance Li-Rich Layered Transition Metal Oxide Cath...

The following RG link is also very useful: Article NCA cathode material: Synthesis methods and performance enha...

Visit also the following useful RG links: Article Recent Developments in Synthesis of xLi2MnO3 · (1 −...

https://www.sciencedirect.com/science/article/am/pii/S001346861631386X

https://www.osti.gov/servlets/purl/1843728

See also the following useful RG links:

http://publications.rwth-aachen.de/record/764599/files/764599.pdf

https://ro.uow.edu.au/cgi/viewcontent.cgi?referer=&httpsredir=1&article=2831&context=theses

Article Synthesis and Characterization of LiNiO2 Nanopowder with Var...

Particle size depends on the synthesis procedure/route not only the citric acid. Citric acid served as the chelating agent.