Altermagnetic behavior in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>OsO</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>: Parallels with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>RuO</

We investigate and compare the electronic structure of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:msub><a:mi>OsO</a:mi><a:mn>2</a:mn></a:msub></a:math> with the extensively studied <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:msub><b:mi>RuO</b:mi><b:mn>2</b:mn></b:msub></b:math>. Calculations show that <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:msub><c:mi>OsO</c:mi><c:mn>2</c:mn></c:msub></c:math> exhibits antiferromagnetism and spin splitting driven by crystal symmetry, a characteristic of altermagnetism and similar to <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:msub><d:mi>RuO</d:mi><d:mn>2</d:mn></d:msub></d:math>. Examination of the Fermi surface, with and without spin-orbit coupling, reveals that <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:msub><e:mi>OsO</e:mi><e:mn>2</e:mn></e:msub></e:math> has lower Fermi group velocities compared to <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:msub><f:mi>RuO</f:mi><f:mn>2</f:mn></f:msub></f:math>, suggesting limited charge carrier mobility in <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:msub><g:mi>OsO</g:mi><g:mn>2</g:mn></g:msub></g:math>. While this characteristic may constrain its performance in high-speed electronic transport applications, it may also enhance stability for spin-based information storage in spintronics. Additionally, comparison of the vibrational properties of these rutile oxide systems demonstrates dynamical stability, typical mass dependent behaviors, and favorable agreement with measured Raman data. The calculated phonon density of states for <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"><h:msub><h:mi>RuO</h:mi><h:mn>2</h:mn></h:msub></h:math> also agrees with our neutron scattering data. These observations substantiate the implications of the electronic and vibrational behaviors in <i:math xmlns:i="http://www.w3.org/1998/Math/MathML"><i:msub><i:mi>OsO</i:mi><i:mn>2</i:mn></i:msub></i:math> and <j:math xmlns:j="http://www.w3.org/1998/Math/MathML"><j:msub><j:mi>RuO</j:mi><j:mn>2</j:mn></j:msub></j:math>, encouraging further investigation of their potential for emerging technological applications.