Lattice dynamics and negative thermal expansion in the framework compound <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>ZnNi</mml:mi><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mi>CN</mml:mi><mml:mo>)</mml:mo></mml:mrow><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math> with two-dimensional and three-dimensional local environments

\mathrm{ZnNi}{(\mathrm{CN})}_{4}is a three-dimensional (3D) framework material consisting of two interpenetrating PtS-type networks in which tetrahedral [\mathrm{Zn}{\mathrm{N}}_{4}]units are linked by square-planar [\mathrm{Ni}{\mathrm{C}}_{4}]units. Both the parent compounds, cubic \mathrm{Zn}{(\mathrm{CN})}_{2}and layered \mathrm{Ni}{(\mathrm{CN})}_{2} are known to exhibit 3D and 2D negative thermal expansion (NTE),...