diff --git a/dumux/material/fluidsystems/1pfluidsystem.hh b/dumux/material/fluidsystems/1pfluidsystem.hh
index 6328972c4e6ca30bcd04561f37e727abb1fe0c79..b243eebc737401d8d70fe6d8f2f71c57eee50a13 100644
--- a/dumux/material/fluidsystems/1pfluidsystem.hh
+++ b/dumux/material/fluidsystems/1pfluidsystem.hh
@@ -298,11 +298,11 @@ public:
      * Molecular diffusion of a compoent \f$\kappa\f$ is caused by a
      * gradient of the chemical potential and follows the law
      *
-     * \f[ J = - D \mathbf{grad} mu_\kappa \f]
+     * \f[ J = - D \mathbf{\grad} \mu_\kappa \f]
      *
      * where \f$\mu_\kappa\f$ is the component's chemical potential,
      * \f$D\f$ is the diffusion coefficient and \f$J\f$ is the
-     * diffusive flux. \f$mu_\kappa\f$ is connected to the component's
+     * diffusive flux. \f$\mu_\kappa\f$ is connected to the component's
      * fugacity \f$f_\kappa\f$ by the relation
      *
      * \f[ \mu_\kappa = R T_\alpha \mathrm{ln} \frac{f_\kappa}{p_\alpha} \f]
diff --git a/dumux/material/fluidsystems/2pimmisciblefluidsystem.hh b/dumux/material/fluidsystems/2pimmisciblefluidsystem.hh
index 437ae592f8bebc7f0d138fe4fadb997160729ab9..8294df10a4582060543f8f2f34b7cb4050f8ebf4 100644
--- a/dumux/material/fluidsystems/2pimmisciblefluidsystem.hh
+++ b/dumux/material/fluidsystems/2pimmisciblefluidsystem.hh
@@ -331,11 +331,11 @@ public:
      * Molecular diffusion of a compoent \f$\kappa\f$ is caused by a
      * gradient of the chemical potential and follows the law
      *
-     * \f[ J = - D \mathbf{grad} mu_\kappa \f]
+     * \f[ J = - D \mathbf{\grad} \mu_\kappa \f]
      *
      * where \f$\mu_\kappa\f$ is the component's chemical potential,
      * \f$D\f$ is the diffusion coefficient and \f$J\f$ is the
-     * diffusive flux. \f$mu_\kappa\f$ is connected to the component's
+     * diffusive flux. \f$\mu_\kappa\f$ is connected to the component's
      * fugacity \f$f_\kappa\f$ by the relation
      *
      * \f[ \mu_\kappa = R T_\alpha \mathrm{ln} \frac{f_\kappa}{p_\alpha} \f]
diff --git a/dumux/material/fluidsystems/basefluidsystem.hh b/dumux/material/fluidsystems/basefluidsystem.hh
index be1dd0423062cee767c0f891e5724037690f51d8..afa62d2c2bf3afe84b1bdaed290b5f6d981fbd41 100644
--- a/dumux/material/fluidsystems/basefluidsystem.hh
+++ b/dumux/material/fluidsystems/basefluidsystem.hh
@@ -89,11 +89,11 @@ public:
      * Molecular diffusion of a compoent \f$\kappa\f$ is caused by a
      * gradient of the chemical potential and follows the law
      *
-     * \f[ J = - D \mathbf{grad} mu_\kappa \f]
+     * \f[ J = - D \mathbf{\grad} \mu_\kappa \f]
      *
      * where \f$\mu_\kappa\f$ is the component's chemical potential,
      * \f$D\f$ is the diffusion coefficient and \f$J\f$ is the
-     * diffusive flux. \f$mu_\kappa\f$ is connected to the component's
+     * diffusive flux. \f$\mu_\kappa\f$ is connected to the component's
      * fugacity \f$f_\kappa\f$ by the relation
      *
      * \f[ \mu_\kappa = R T_\alpha \mathrm{ln} \frac{f_\kappa}{p_\alpha} \f]
diff --git a/dumux/material/fluidsystems/h2on2liquidphasefluidsystem.hh b/dumux/material/fluidsystems/h2on2liquidphasefluidsystem.hh
index 4886050a0c6c215107e1bac27fce4311a24bd04b..cf026bb819120351493908b3f0230739ca48234a 100644
--- a/dumux/material/fluidsystems/h2on2liquidphasefluidsystem.hh
+++ b/dumux/material/fluidsystems/h2on2liquidphasefluidsystem.hh
@@ -458,7 +458,7 @@ public:
      * Molecular diffusion of a compoent \f$\kappa\f$ is caused by a
      * gradient of the chemical potential and follows the law
      *
-     * \f[ J = - D \mathbf{grad} mu_\kappa \f]
+     * \f[ J = - D \mathbf{\grad} \mu_\kappa \f]
      *
      * where \f$\mu_\kappa\f$ is the component's chemical potential,
      * \f$D\f$ is the diffusion coefficient and \f$J\f$ is the
diff --git a/dumux/material/fluidsystems/spe5fluidsystem.hh b/dumux/material/fluidsystems/spe5fluidsystem.hh
index 74aabc88672f05352f3c22b91b1096ac8e8303f7..49b0753caea3b06d26b451e21c0640189a7d8734 100644
--- a/dumux/material/fluidsystems/spe5fluidsystem.hh
+++ b/dumux/material/fluidsystems/spe5fluidsystem.hh
@@ -441,11 +441,11 @@ public:
      * Molecular diffusion of a compoent \f$\kappa\f$ is caused by a
      * gradient of the chemical potential and follows the law
      *
-     * \f[ J = - D \grad mu_\kappa \f]
+     * \f[ J = - D \grad \mu_\kappa \f]
      *
-     * where \f$\mu_\kappa\\f$ is the component's chemical potential,
+     * where \f$\mu_\kappa\f$ is the component's chemical potential,
      * \f$D\f$ is the diffusion coefficient and \f$J\f$ is the
-     * diffusive flux. \f$mu_\kappa\f$ is connected to the component's
+     * diffusive flux. \f$\mu_\kappa\f$ is connected to the component's
      * fugacity \f$f_\kappa\f$ by the relation
      *
      * \f[ \mu_\kappa = R T_\alpha \mathrm{ln} \frac{f_\kappa}{p_\alpha} \f]